BECOM-1

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BECOM 1 Exam 2 (2018)

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During intensive exercise, skeletal muscle metabolites are released in high amounts into the bloodstream. If unchecked, these metabolites would cause a bottoming out of blood pressure. What mechanism is in place that keeps a check on these products, stabilizing blood pressure?
Sympathetic stimulation of β2 receptors
Sympathetic stimulation of α2 receptors
Parasympathetic stimulation of M2 receptors
Sympathetic stimulation of β1 receptors
Sympathetic stimulation of α1 receptors
When there is a bloodborne infection, cells of the immune system produce vast amounts of nitric oxide to destroy the pathogen. This dilates blood vessels and can cause blood pressure to plummet – a condition called septic shock. Which of the following is an additional reason for why an accumulation of NO could be dangerous?
B & C
Peroxynitrites (ONOO-) can break down into Nitrogen dioxide radicals (•NO2) and hydroxyl radicals (•OH)
A & C
Excess amounts of nitric oxide can react with superoxide radicals forming peroxynitrite (ONOO-)
Excess amounts of nitric oxide can react with free oxygen radicals forming peroxynitrite (ONOO-)
One of your patients is Type II diabetic. In order to help them increase their insulin sensitivity you recommend more frequent exercise which you expect will:

Increase skeletal muscle of utilization of insulin during exercise only
Lead to higher levels of insulin in the body
Decrease skeletal muscle utilization of insulin during rest only
Increase insulin synthesis by pancreatic beta cells
Promote recruitment of more GLUT4 receptors
Von Gierke disease, is the most common of the glycogen storage diseases. This genetic disease impairs the ability of the liver to produce free glucose from glycogen and from gluconeogenesis. A deficiency in which of the following enzymes would lead to this disease?
PFK-1
Glucose-6 Phosphatase
2,3-BPG mutase
PEPCK
Pyruvate carboxylase deficiency
Which of the following is true regarding the conductance velocity of an action potential?
Preganglionic fibers often have a slower conduction velocity as compared to postsynaptic fibers since they are unmyelinated
Myelination decreases capacitance by allowing action potentials to “jump” from node to node, increasing conduction velocity
Myelin decreases conduction velocity by providing insulination for the axon
Axons with smaller diameters have increase conduction velocity
Myelination creates a greater surface area to allow for ion exchange across membranes
After consuming glucose, insulin production is turned on, whereas glucagon is turned off. Which of the following is true in the fed state?
Lactate production is increased, resulting in an increase in glycogen synthesis.
Fatty acids are broken down to maintain blood glucose levels.
Glycogen synthesis is inhibited by the increase in insulin.
Glycogen synthesis is stimulated by insulin and stored in the liver and skeletal muscle.
Fatty acid synthesis is inhibited by glucagon to maintain blood glucose levels.
As a third year medical student, your resident shows you a patient file showing a confirmed diagnosis of chronic granulomatous disease, which is caused by an enzyme mutation in NOX-2. Where is this enzyme located that it would lead to symptoms associated with this condition?
The outer mitochondrial membrane
Intracellular phagosome membrane
Extracellular membrane
This is cause by a free enzyme in the cytosol
The inner mitochondrial membrane
Which of the following is true regarding succinate dehydrogenase?
It requires Vitamin B1 (Thiamine)
It requires Vitamin B7 (Biotin)
It oxidizes NADH → NAD+
It produces GTP in its reaction of succinate → fumarate
It is involved in both the ETC and TCA cycle
A patient comes to your office with kidney and liver failure. You suspect that methylmalonic acidemia might be their diagnosis which would mean that they are likely deficient in which of the following enzymes?
Vitamin B12
Vitamin B3
Vitamin B2
Vitamin B5
Vitamin B1
Alcoholics typically have markedly diminished function of pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase due to decreased dietary absorption of:
Riboflavin
Succinate
Thiamine
S-adenosyl methionine
Biotin
Which of the following is an example of a positive feedback mechanism?
Liver pyruvate kinase activity is up-regulated by fructose-1,6-bisphosphate
Stretch receptors in the cervix signal the pituitary to release oxytocin
Pyruvate dehydrogenase is inhibited by acetyl-CoA
Lactate is transported out of muscle tissue so that muscle lactate dehydrogenase can continue to recycle NAD+ against a low product concentration gradient
While epinephrine by nature has a global effect on several sympathetic adrenergic receptors, upon its initial release, to which receptor type with it bind to preferentially?
α2
α1
β1
β3
β2
When there is an increased stimulus, there is an increased frequency in action potential firing. What are some of the effects this could have?
Increased acetylcholine release in synaptic cleft causing a greater depolarization of cell to cause more frequent firing and greater calcium release
A, B
A, C
Greater neurotransmitter release from axon terminal which causes a greater target response
The neuron will hyper-polarize
Change in amplitude of the action potential
Once a vessel is damaged, platelets start to cling to the injured site and release chemicals that attract more platelets. The platelets continue to pile up and release chemicals until a clot is formed. Blood clotting is an example of:
Negative Feedback
Low Gain System
Positive Feedback
None of the Above
High Gain System
An action potential can serve many functions in the body, what are some of the effects of blocking an action potential?
The cell will always remain depolarized
Cellular response to allow for muscle contraction and neurotransmitter release
Information delivery to the central nervous system
Blocking in sensory nerves can allow for analgesic effects
Which of the following is true regarding the organization of the autonomic nervous system?
Postganglionic fibers are usually unmyelinated and thus conduct action potentials at a slower rate
N2 receptors are located at the neuromuscular junction
Somatic motor neurons have a large diameter, allowing for them to conduct action potentials faster
Arteriolar smooth muscle is only innervated by the Parasympathetic nervous system
Sympathetic preganglionic fibers are long, myelinated fibers that synapse with postganglionic fibers extremely close to the target organ
Hemochromatosis is a disease in which too much iron builds up in your body. The fenton reaction explains why this buildup of iron can be so dangerous. Which of the following best describes the Fenton reaction?
Fe2+ can react with free oxygen, producing hydroxide
Fe2+ can react with other metals such as Cu+ to produce hydroxide
Fe2+ can react with hydrogen peroxide, producing hydroxyl radicals
Fe2+ can react with hydrogen peroxide, producing superoxide radicals
Fe2+ can react with free oxygen, producing superoxide radicals
A neuron has a threshold of -45 mV. Resting membrane potential is -60 mV. A depolarization stimulus of 10 mV is applied. What is the effect?
Initially, the neuron will hyperpolarize but then it will depolarize
There will be no effect
The neuron will depolarize however an action potential will not fire
An action potential will fire
The neuron will hyper-polarize
How much time does it take for glycogen to be depleted when one is in a basal state?
4-5 hours
1-2 days
24-36 hours
Glycogen is never depleted since the breakdown of all fuel sources contributes to glycogen stores
12-14 hours
A patient comes in with CO poisoning. What can be said about the likelihood (at first) of membrane threshold being reached compared to the normal?

The cell is hyperpolarized, it is less likely to reach threshold.
The cell is depolarized, it is less likely to reach threshold.
The cell is depolarized, it is more likely to reach threshold.
The cell is hyperpolarized, it is more likely to reach threshold.
You are doing rotations in the Emergency Department when a 25-year-old female patient is brought in via ambulance. The paramedics tell you that she is in anaphylaxis due to a bee sting. You’re a super smart med student, so you know that anaphylactic shock is associated with systemic vasodilation that causes low blood pressure. Which of the following would be the best course of action in order to fix this associated vasodilation and drop in blood pressure?
You should administer a high dose of epinephrine since α-receptors have a lower affinity for Epinephrine than that of ß-receptors.
You should administer a low dose of epinephrine since α-receptors have a lower affinity for Epinephrine than that of ß-receptors
You should administer a low dose of epinephrine since α-receptors have a higher affinity for Epinephrine than that of ß-receptors
You should administer Viagra
You should administer a high dose of Epinephrine since α-receptors have a higher affinity for Epinephrine than that of ß-receptors.
The X-linked genetic disorder known as Leigh disease presents with mortally high levels of lactic acid in the blood due to a PDH E1 defect. With this disorder, the PDH E1 subunit would most likely display difficulty binding to which essential coenzyme?
TPP
Lipoate
FAD
Lipoamide
Pantothenate
Which of the following combinations of membrane potential (Vm) and equilibrium potential (Eion) for either a cation or anion would result in an overall decrease in membrane potential if: The channel for the specific anion or cation was open and uninhibited. Concentration differences between the cytosol and EC anion/cation are negligible.
Vm = -70, Eanion = -100
Vm = -90, Eanion = -100
Vm = -90, Ecation = -120
Vm = -70, Ecation = -80
Vm = -90, Eanion = 80
The autonomic nervous system has many global targets across both sympathetic and parasympathetic pathways. Which of the following is dually innervated by both of these divisions?
Arteriolar smooth muscle
Cardiac muscle
Coagulation cascade
Kidneys
Sweat glands
Gene was recently diagnosed with hypertension and put on enalapril, an ACE inhibitor. He wants to know how it works, so you tell him, in layman’s terms:
It blocks the formation of Renin which then prevents the body from creating a hormone called aldosterone which thus decreases blood pressure
It blocks an enzyme that prevents a hormone that tells the body to not absorb water thus decreasing blood pressure
It blocks a hormone that is secreted from the pituitary gland causing him to absorb water thus decreasing blood pressure
It blocks a hormone that is secreted from the pituitary gland causing him to not absorb water thus decreasing blood pressure
It blocks an enzyme that prevents a hormone that tells the body to absorb water thus decreasing blood pressure
Wernicke-Korsakoff syndrome is a neurological disorder characterized by mental confusion, amnesia (a permanent gap in memory), and impaired short-term memory. Which of the following enzymes would have reduced function due to this disorder?
Pyruvate carboxylase
Malonate Dehydrogenase
Lactate Dehydrogenase
Pyruvate Dehydrogenase
Methylmalonyl-CoA mutase
What unique property of non-alpha tocopherols makes them an essential part of a good diet?
Its ability to inhibit COX, 5LOX and RNS
Collaborative function with ascorbate
The ability to neutralize toxic NAPQI
Its higher favorability for oxyradicals
Its higher concentration in tissues than alphaT
Cystic Fibrosis is a disease caused by a mutation in which of the following types of channels?
Ligand gated chloride channels
Voltage gated chloride channels
Ligand gated calcium channels
Mechanically gated chloride channels
Voltage gated calcium channels
Ischemic strokes occur when the arteries to your brain become narrowed or blocked, causing severely reduced blood flow. Which of the following best describes how a patient’s ETC would be affected if they were experiencing a stroke?
The lack of blood flow would directly inhibit the function of Complex IV and a subsequent release of reactive oxygen species from Complex I and III
The lack of blood flow would directly inhibit the function of Complex I and cause a subsequent release of reactive oxygen species from Complex I
The lack of blood flow would directly inhibit the function of Complex II and cause a subsequent release of reactive oxygen species from Complex I and II
The lack of blood flow would directly inhibit the function of Complex III and cause a subsequent release of reactive oxygen species from Complex I and III
The lack of blood flow would directly inhibit the function of Complex IV and cause a subsequent release of reactive oxygen species from Complex I and II
Your friend in medical school asks why depolarizing the membrane (such as in a state of acidemia), eventually leads to fewer action potentials. The best answer is:
Depolarization, if prolonged, leads to inactivated Na+ channels.
Depolarization makes the cell more permeable to Cl-, which eventually hyperpolarizes the membrane.
Depolarization has a boomerang effect and eventually leads to hyperpolarization.
Did you hear the one about global warming? It depolarizes!
Depolarization causes degradation of K+ channel proteins
Which part of a K⁺ channel subunit is primarily responsible for K⁺ selectivity over Na⁺?
S5 (outer helix)
P segment
Hyrophospate end
Alpha binder
S6 (inner helix)
With extreme parasympathetic stimulation present in situations like organophosphate poisoning, you would expect which symptoms to be ABSENT?
Increased cardiac force of contraction
Miosis
Defecation
Extreme salivation
Muscle spasm
Jenna fell off her bike scraping her knee. This started a cascade of cellular processes: her knee started bleeding, turned red and was painful. Her broken endothelial cells release cytokines which signal thrombocytes to release more cytokines thus activating additional thrombocytes to clot and stop the bleeding. This is an example of:
Feedback inhibition
Returning to homeostasis
Feed-forward activation
Anti-inflammatory response
Anticoagulant response
Emily is a 62-year-old obese female BP=186/92, resting HR=72 bpm. She is a very sedentary, non-smoker. You diagnose her with hypertension. As her primary care physician, you prescribe the beta-1 antagonist metoprolol for treatment of her condition. Metoprolol will help lower Emily’s blood pressure through all of the following EXCEPT?
Kidney: decreased renin release
Kidney: decreased water conservation
Arterioles: decreased arteriolar vasoconstriction
Heart: decreased heart rate
Heart: decreased force of contraction
The conversion of Pyruvate to Acetyl CoA is regulated by all of the following EXCEPT:
Acetyl CoA
NAD+
CoASH
FADH2
FADH2
The activity of pyruvate dehydrogenase complex is a crucial process in carbohydrate metabolism which is regulated by the activity of two enzymes. What would you expect to see in a patient with a deficiency in the PDC kinase enzyme?
Increased activity of pyruvate dehydrogenase complex compared to a person with normal amount of PDC kinase enzyme
Decreased activity of pyruvate dehydrogenase complex compared to a person with normal amount of PDC kinase enzyme
No change in the activity of pyruvate dehydrogenase complex compared to a person with normal amount of PDC kinase enzyme
None of the above
After consuming a high carbohydrate meal, your body begins to break down and take in the glucose from the meal and you are considered to be in the fed state. Which of the following occurs ONLY in the liver?
Production and storage of glycogen
PFK1 activity decreases in response to an increased amount of ATP & citrate
Hexokinase activity decreases in response to increased amount of G-6-P in the cell
Pyruvate kinase activity decreases in response to increased amount of ATP and alanine
Both C and D
Dr. Moffitt is running yet another ultramarathon. As she approaches mile 20, she decides to reach for her gel packet tucked conveniently within her fanny pack in order to get some energy. The gel packet contains a high amount of Fructose. Which of the following is true regarding Dr. Moffitt’s decision to consume this gel packet?
Since she is undergoing prolonged exercise, Dr. Moffitt is burning ATP at an high rate and therefore can utilize the Fructose without producing an abundance of fat
This is a good choice since Fructose will initiate Gluconeogenesis in the liver
It’s obviously a mistake, Fructose will be converted to fat which won’t be burned in time to give Dr. Moffitt energy
A glucose-only gel packet would have given her the same amount of energy
Fructose will undergo glycolysis without being regulated, therefore her consumption of this sugar will lead to an accumulation of fat which can be burned for energy
You have been having troubles lately and your OMS1 friend decides to play doctor and suggest that you seek out some natural sources for Serotonin, postulating that this will help you sleep and feel better. Of her suggestions, which one could lead to more serotonin?
Dopa decarboxylase that is sold on the corner near the riverfront.
Glutamate that is in MSG and can be gotten at Harps.
Choline which she swears is sold by the pound at the Farmer’s Market on Saturday.
Tryptophan which is in turkey, they are on sale at Aldi.
Tyrosine in a supplement from Walmart.
Which of the following would be a long-term effect of hemolytic anemia?
Increase in erythropoietin
Haldane Effect
Increase in 2,3-BPG
Increase in bicarbonate
Bohr effect
Which of the following enzymes is involved in a reaction unique to gluconeogenesis?
Phosphoglycerate kinase
Phosphoglyceromutase
Phosphoglucose isomerase
Phosphofructokinase-1
Pyruvate carboxylase
Which branch of the nervous system is the best at quickly conducting signals to its effectors?
Autonomic sympathetic muscarinic
Autonomic parasympathetic muscarinic
Autonomic sympathetic adrenergic
Somatic motor
Autonomic sympathetic cholinergic
Denervation supersensitivity describes that after denervation of a cell, the loss of available neurotransmitter causes the cell to…
Regrow the nerves from the cell end
Become less sensitive to other nerves that innervate it
Learn to respond to different neurotransmitters
Up-regulate receptors, in essence looking for transmitters
Experience necrosis from lack of stimulation
Which of the following is a anapleurotic reaction that occurs in the TCA cycle?
Succinyl CoA → Heme
Glutamate → citrate
Lysine → Succinate
Citrate → Fatty Acids
Aspartate → Oxaloacetate
Caffeine is a potent inhibitor of phosphodiesterase. Considering this, in which of the following might caffeine have a stimulatory effect?
Sympathetic ganglion
Sweat glands
Presynaptic sympathetic nerve terminals
Vascular smooth muscle
Cardiomyocytes
Pig insulin was regularly administered to diabetic patients before the structure of human insulin was discovered. Now that the structure is known, doctors are able to administer the active portion of insulin, while still being able to measure the amount of insulin being produced by the body. Which part of human-secreted insulin is measured?
Insulin
A-chain
C-peptide
B-chain
Proinsulin
The glycolytic enzyme PFK-1 would have decreased function under which of the following conditions?
High concentrations of F-2,6-BP
Mutation resulting in decreased activity at the ATP effector binding site
High concentrations of ATP
Low concentration of citrate
High concentrations of AMP
You are doing clinical rotations in the Emergency Department when a patient comes in who had overdosed on Aspirin. Their symptoms include hyperventilation, vomiting, dehydration, double vision, fever, and feeling faint. A resident asks you to explain the reasoning for why this patient is exhibiting a fever. What are you going to tell them?
The fever due to the body’s immunological response to the overabundance of Aspirin
The patient probably has an associated infection.
Aspirin activates UCP1 causing thermogenesis and dissipation of heat from brown adipose stores
The body creates a fever in order to provide a more suitable environment for the enzymes responsible for metabolizing the Aspirin
High dose aspirin works as a chemical uncoupler, producing excess heat with the associated energy release
In someone infected by the Clostridium botulinum bacteria, there is a complete blockade of a key neurotransmitter to the respiratory muscles. By what means does the botulinus toxin produce this fatal effect?
Blocking the release of acetylcholine at the presynaptic terminals
Inhibiting the action of acetylcholine esterase
Inhibition at the site of the postsynaptic muscarinic receptors
Blocking the acetylcholine receptors at the motor plate
Depletion of acetylcholine at the presynaptic terminal
A patient has bloodwork done two hours after consuming a sugary drink. Since consuming the drink, the patient has consumed no other food or beverages. The patient’s blood glucose level is 163 mg/dL. What can be said about the patient?
The patient is not producing insulin.
The patient is not producing insulin.
The patient is considered pre-diabetic.
The patient’s results are considered normal.
The patient is considered diabetic.
Potassium channels allow for potassium to leave the cell. What prevents sodium from using this channel?
Sodium is negatively charged so it sticks to the positively charged sides of the channel.
Sodium does not form waters of hydration so the selectivity filter does not recognize it.
Sodiums waters of hydration do not align with the selectivity filter so they do not strip the waters off
Potassium is much smaller than sodium so it is able to pass based on size.
Sodium is too small to pass through the channel so it diffuses through without a channel.
Which of the following is correct in regards to graded potentials and action potentials?
GP and AP can both only be depolarized
AP can be initiated with above threshold graded potentials at axon hillock; GP are initiated in ions through channels
AP always have the same strength of signal and have a refractory period that must be obeyed; GP cannot have summation
Graded potentials (GP) occur in the axon hillock; action potentials (AP) occur in the dendrites/cell bodies
GP only occur with voltage gated ion channels; AP can occur with any type of ion channel
A neuron fires an action potential. From that we know that:
Neurons are magic and they fire when they feel like it.
The neuron received a balance of excitatory inputs and inhibitory inputs but that the excitatory inputs were closer to the axon hillock.
The neuron received only excitatory inputs.
The neuron received only inhibitory inputs.
The neuron received enough excitatory inputs to fire an action potential even if inhibitory inputs were received as well.
For a combination of reasons, high consumption of alcohol leads to a depletion of which carbohydrate metabolite?
Glycogenin
3-phosphoglycerate
Oxaloacetate
1,2-bisphosphoglycerate
Pyruvate
Orthostatic hypotension occurs when a person’s blood pressure falls when suddenly standing up from a lying or sitting position. It occurs predominantly by delayed constriction of the lower body blood vessels, which is normally required to maintain an adequate blood pressure when changing position to standing. As a result, blood pools in the blood vessels of the legs for a longer period and less is returned to the heart, thereby leading to a reduced cardiac output. This is an example of:
Negative Feedback
Positive Feedback
None of the Above
High Gain System
Low Gain System
In a neuron where potassium channels are inappropriately opened, what will be the effect on the excitability of the neuron.
It will be less excitable due to hyperpolarization.
It will be more excitable due to depolarization.
It will be unaffected because the Na/K pumps are still working.
The potassium channel will reset before any effect can be noticed.
This will cause a chlorine channel to open and balance out the effect.
Ahsan, a mentally exhausted medical student, decided to take a study break and go for a hike at Devil’s Den. He accidentally travelled off the beaten path when he heard some unusual noises coming from the brush. Luckily Ahsan is a highly trained eagle scout and recognized the sounds immediately as the call of a cougar. He sprung into action, boldly running from the noise and flooding his body with adrenaline. Assuming that Ahsan had eaten a meal high in carbohydrates within an hour of this occurrence, which of the following is true?
His high BGL would trigger a release of Insulin and the dephosphorylation of Glycogen Synthase by Protein phosphatase.
Epinephrine will activate a tyrosine kinase receptor signaling pathway causing the breakdown of Glycogen.
Glucagon would be released causing the activation of PKA and the subsequent dephosphorylation of Glycogen synthase and phosphorylase kinase.
Despite his high BGL, Epinephrine will work in a similar manner to that of Glucagon causing the phosphorylation of Glycogen synthase and Glycogen phosphorylase.
Epinephrine will activate a similar signaling cascade to that of Insulin, causing an activation of PKB (Akt) and subsequent phosphorylation of Glycogen synthase.
Damage to the ETC by means of cyanide poisoning would lead to leakage of electrons through which channels?
Complex I
Complex II
Complex III
Complex IV
Complex I and III
After determining that your patient has pheochromocytoma, a tumor of the adrenal medulla, you order a urine test expecting elevated levels of metabolites for primarily which small molecule neurotransmitter?
Nitric oxide
Dopamine
Epinephrine
Norepinephrine
Acetylcholine
A patient is excreting high levels of VMA (3-Methoxy-4-hydroxymandelic acid) in their urine. This would suggest high levels of which neurotransmitter(s)?

Epinephrine
Norepinephrine
Dopamine
A & B
A & C
Which division of the autonomic nervous system has the shortest postganglionic distance?
Sympathetic cholinergic
Parasympathetic cholinergic
Sympathetic muscarinic
Parasympathetic muscarinic
Nicotinic 1 motor plate
Vagal maneuvers involve various techniques of stimulating the vagus nerve (CN X) in order to elicit a specific response in the autonomic nervous system. For example, health care providers may trigger the gag reflex in their patient to stimulate this nerve and provide a therapeutic effect. Which of the following is most likely the intended effect of a vagal maneuver?
Miosis
Bronchodilation
Decrease gut motility
Decrease heart rate
Increase sweat production
Which of the following is occurring at the point in the graph depicted by the red arrow?
K+ inactivation gates are opening
Na+ inactivation gates are closed
K+ activation gates are closing
None of the above
Na+ activation gates are open
Albuterol is a commonly used beta 2 agonist. What physiological effect with occur upon treatment with albuterol?
Decrease in heart rate
Increased sweat production
Constriction of vascular smooth muscle
Inhibition of adenylyl cyclase
Dilation of bronchiolar smooth muscle
The market for antidepressants and antipsychotics in the pharmaceutical industry is massive, with many drugs targeting the serotonergic synapse. Which of the following would be a viable method for relieving the symptoms of depression at this site?
Upregulating the expression of monoamine oxidase (MAO)
Consuming a diet low in tryptophan
Inhibition of pre-synaptic 5-HT storage
Inhibition of re-uptake by monoamine transporters
Selective deactivation of the 5-hydroxytryptophan decarboxylase enzyme
Which of the following is considered to be the most dangerous reactive oxygen species (ROS)?
Superoxide radical
Hydroxide ion
Oxygen
Hydrogen peroxide
Hydroxyl radical
In the cold northern winters, you many times will see people out at bars not wearing jackets who claim that they are not cold, is this problematic? Why or Why not?
No because Northerners have excess brown fat reserves
Yes, because the only reason they don’t feel cold is because they are shivering which causes muscle contractions which will not regulate body temperature
Yes because they feel warm because their body is vasodialating causing heat to leave their skin
Yes because their parasympathetic nervous system becomes activated which shunts blood to their core causing them to feel warmer while causing frostbite
No, because hoes don’t get cold
Glucagon signaling will do which of the following in the target cell?
Deactivate glycogen phosphorylase-a
Activate protein phosphatase-1
Lower 5′-AMP levels
Decrease cAMP levels
Increase glucose-1-phosphate levels
Which of the following is an activator of pyruvate kinase in the liver?
None of the above
GTP
Fructose-1,6-P
Alanine
ATP
Metoprolol is a beta 1 blocker often given to patients with high blood pressure. Patients who are prescribed this medication often stop taking it because of annoying side effects. What other side effect can be contributed to the beta 1 blocking ability of Metoprolol?
Rashes
Dry Eyes
Bronchiolar constriction
Excess sweating
Weight gain
Patent ductus arteriosus is a heart defect in the pulmonary artery that carries oxygen-poor blood to the lungs and the artery that carries oxygen-rich blood to the rest of your body. How would this condition affect the rest of the body in terms of membrane potential?
It would not affect membrane potentials, it would have an effect on hemoglobin binding causing a shift to prefer myoglobin.
It repolarizes the membrane before there is an action potential, so the body cannot effectively carry oxygen throughout the body
It hyperpolarizes the membrane because there is an influx of K making it harder to reach threshold
It depolarizes the membrane because there is no Na/K pump action because there is a lack of ATP
It causes the threshold to increase meaning it takes a bigger stimulus and makes it harder for oxygen to be transported throughout the body
Which enzyme in carbohydrate metabolism works as a tight control point for both the anabolic and catabolic pathways, ensuring that glycolysis and gluconeogenesis are not both active at the same time?
Pyruvate carboxylase
FBPase-1
G-6-Pase
Phosphoglucomutase
PFK-2
Alkalosis has a profound effect on neurons. It is most notable in which of the following?
States of diabetic ketoacidosis which lead to coma.
Epilepsy where patients will attempt to blow off CO2, hyperventilate, elevate their blood pH and induce seizures
B & D
States of hypoxia where the low oxygen reduces availability of ATP for the Na/K pumps.
Cause the neuron to reverse polarity and send all action potentials back up the dendrites to their origins.
Angel waddles into class one morning complaining of intense bum soreness that she says is from her CrossFit “workout” the previous evening. This soreness is in part due to the accumulation of lactate. Which of the following best explains the reasoning for why there is an accumulation of lactate during heavy intense exercise?

The TCA cycle is inhibited by heavy intense exercise
Pyruvate is being generated at a higher rate than it can enter the TCA cycle
The Ca2+ produced from muscle contraction works to upregulate Lactate DH
Lack of oxygen availability
Lactate is necessary to perform Gluconeogenesis
What is TRUE about fructose metabolism?

It’s the most efficient fuel source for ATP
Fructose enters glycolysis after the key regulatory step, allowing it to go unchecked and produce an abundance of fat in the liver
The relatively high ratio of glucose to fructose in high fructose corn syrup is what makes the substance so bad for you
Conversion of fructose-1 phosphate to fat is a highly regulated process
Regulation of fructose is accomplished by PFK-2, which converts fructose 1-phosphate into fructose 2,6-bisphosphate
Lethal injections contain potassium chloride which works to stop the heart. Why is this an effective method of euthinasia?
It causes more potassium to be in the extracellular fluid making it harder for the cell to reach threshold so there is less action potentials being reached and thus the heart stops beating
It causes Na gates to remain inactive which means it cannot return to resting membrane potential causing cessation of action potentials making the heart unable to pump
It causes K gates to remain open which means it cannot return to resting membrane potential causing excessive action potentials which shock the heart until it stops working
It causes K gates to remain open which means it cannot return to resting membrane potential causing cessation of action potentials making the heart unable to pump
It causes Na gates to remain inactive which means it cannot return to resting membrane potential causing excessive action potentials which shock the heart until it stops working
Lauren, an OMS I student, is celebrating her outstanding performance on the anatomy exam by hitting the dance floor at the Electric Cowboy (she’s got Flossing down!). She realizes that she forgot to eat dinner, but doesn’t want to leave to grab a meal. She opts to pile on the drinks because, after all, alcohol has carbohydrates and she’ll be satisfied (at least for a little bit). How will her body respond?
Initial hypoglycemia, but soon her body will become hyperglycemic
NADH levels will decrease but rapidly start increasing
Increasing gluconeogenesis
Lowering the activity of aldehyde dehydrogenase
Initial hyperglycemia, but soon her body will become hypoglycemic
Stimulants, colloquially referred to as “uppers,” are drugs that increase activity of the central nervous system by eliciting sympathomimetic effects. Which of the following is most likely a symptom of someone who had taken a stimulant?
Reduced blood pressure
Miosis
Profuse sweating
Increased digestion
Decreased heart rate
In preparation for board game night, Seth and Ed each brought their favorite snacks to enjoy throughout the night. Shortly after eating all of his doughnuts, Seth was already hungry again. Ed, however, was still feeling quite content after eating his quinoa and mushrooms. What is the likely cause for this discrepancy?
Seth’s doughnuts have a high glycemic index, causing a large, but short spike in blood glucose
Seth’s doughnuts absorb at a slower rate, so he isn’t getting as much energy from them
Ed’s quinoa has a high glycemic index, causing a prolonged spike in blood glucose
Seth’s donuts had a high abundance of Fructose, causing glycolysis to occur unchecked and create an abundance of ATP
The fructose content in Ed’s quinoa was converted to fat, which has twice the calories of carbs, it’s simple science.
A patient is diagnosed with hypoxia, which of the following is NOT true about the patient with regard to membrane potentials in B cells of the pancreas?
Voltage sensitive Ca2+ channels are open
Insulin is not being secreted
ATP sensitive K+ channels are open
Vm is increasing
The membrane is hyperpolarizing
The ganglionic blocking drug hexamethonium, which antagonizes N₂ receptors, is administered intravenously. Which of the following would be most likely to be observed in response to administration of this drug?
Tachycardia or bradycardia equally likely, decreased blood pressure
Bradycardia, decreased blood pressure
Tachycardia, increased blood pressure
Tachycardia, decreased blood pressure
Tachycardia or bradycardia equally likely, increased or decreased blood pressure also equally likely
Tonic control regulates physiological parameters in an up-down fashion. Match the effects of the neurotransmitter and the correct nervous system with its associated physiological effect.
Increased acetylcholine would be present for the sympathetic nervous system and cause vasoconstriction and therefore hypoventilation
Decreased norepinephrine for the sympathetic nervous system would cause a decrease in signal rate and therefore blood vessel dilation to cause an increase in blood pressure
Increased acetylcholine would be present for the parasympathetic nervous system and cause vasoconstriction and therefore hyperventilation
Decreased norepinephrine for the sympathetic nervous system would cause a decrease in signal rate and therefore blood vessel dilation to cause a decrease in blood pressure
Increased norepinephrine for the sympathetic nervous system would cause a decrease in signal rate and therefore blood vessel dilation to cause a decrease in blood pressure
Following extreme trauma, the body would use which TCA intermediate to replace lost heme?

Succinyl CoA
Oxaloacetate
Alpha-ketoglutarate
Succinate
Citrate
You are on a pediatrics rotation when a 5-year-old female patient is brought into the clinic by their mother. The patient is severely obese. However, the mother mentions that her daughter’s nutrition is good but she is constantly hungry. What is the next thing you should do?
Test for brain damage within the hypothalamus
Test for AMPK deficiency
Refer them to a nutritionist
Test for Type I Diabetes mellitus
Test for a Leptin deficiency
You are on rotations in an underserved primary care clinic when you come across a patient who can’t stop talking about the importance of antioxidants. They tell you that they researched it on “the Google machine” and that they know all there is to know about antioxidants. When asked, the patient revealed that they’ve been taking Vitamin E for the past 5 years in order to rid their body of reactant radicals. What should you tell them?
Keep doing what they’re doing, Vitamin E is a great source of gamma-tocopherol which is important in ridding the body of radicals
Keep doing what they’re doing, Vitamin E is a great source of alpha-tocopherol which is important in ridding the body of radicals
While Vitamin E is a great source of gamma-tocopherol, it doesn’t include the other “non-gamma” tocopherols which are also important in ridding the body of free radicals
They are mistaken and should actually be taking Vitamin D to get the effect they’re wanting
While Vitamin E is a great source of alpha-tocopherol, it doesn’t include the other “non-alpha” tocopherols which are also important in ridding the body of free radicals
Which glycolytic intermediates have sufficient energy to drive the production of ATP via substrate level phosphorylation?
1,3-bisphosphoglycerate and phosphoenolpyruvate
F1P and pyruvate
Glyceraldehyde 3-phosphate and 3-phosphoglycerate
G6P and dihydroxyacetone phosphate
1,3-bisphosphoglycerate and phosphoenolpyruvate
87 out of
Time is Up!
Take the 2019 test
Welcome to your BECOM-1 Exam 2 (2019)

Once a vessel is damaged, platelets start to cling to the injured site and release chemicals that attract more platelets. The platelets continue to pile up and release chemicals until a clot is formed. Blood clotting is an example of:Once a vessel is damaged, platelets start to cling to the injured site and release chemicals that attract more platelets. The platelets continue to pile up and release chemicals until a clot is formed. Blood clotting is an example of which of the following?
Negative Feedback
Positive Feedback
High Gain System
Low Gain System
None of the Above

In the cold northern winters, you many times will see people out at bars not wearing jackets who claim that they are not cold, is this problematic? Why or Why not?
answer 1
answer 2

Which of the following would be a long-term effect of hemolytic anemia?
Bohr effect
Increase in erythropoietin
Increase in 2,3-BPG
Haldane Effect
Increase in bicarbonate

Which of the following is an example of a positive feedback mechanism?
Liver pyruvate kinase activity is up-regulated by fructose-1,6-bisphosphate
Stretch receptors in the cervix signal the pituitary to release oxytocin
Lactate is transported out of muscle tissue so that muscle lactate dehydrogenase can continue to recycle NAD+ against a low product concentration gradient
Pyruvate dehydrogenase is inhibited by acetyl-CoA

Gene was recently diagnosed with hypertension and put on enalapril, an ACE inhibitor. He wants to know how it works, so you tell him, in layman’s terms:
It blocks a hormone that is secreted from the pituitary gland causing him to not absorb water thus decreasing blood pressure
It blocks an enzyme that prevents a hormone that tells the body to absorb water thus decreasing blood pressure
It blocks a hormone that is secreted from the pituitary gland causing him to absorb water thus decreasing blood pressure
It blocks an enzyme that prevents a hormone that tells the body to not absorb water thus decreasing blood pressure
It blocks the formation of Renin which then prevents the body from creating a hormone called aldosterone which thus decreases blood pressure

Jenna fell off her bike scraping her knee. This started a cascade of cellular processes: her knee started bleeding, turned red and was painful. Her broken endothelial cells release cytokines which signal thrombocytes to release more cytokines thus activating additional thrombocytes to clot and stop the bleeding. This is an example of:
Feed-forward activation
Feedback inhibition
Returning to homeostasis
Anticoagulant response
Anti-inflammatory response

Which of the following combinations of membrane potential (Vm) and equilibrium potential (Eion) for either a cation or anion would result in an overall decrease in membrane potential if: The channel for the specific anion or cation was open and uninhibited. Concentration differences between the cytosol and EC anion/cation are negligible.
Vm = -90, Eanion = -100
Vm = -70, Ecation = -80
Vm = -90, Ecation = -120
Vm = -70, Eanion = -100
Vm = -90, Eanion = 80

Potassium channels allow for potassium to leave the cell. What prevents sodium from using this channel?
Potassium is much smaller than sodium so it is able to pass based on size.
Sodium is negatively charged so it sticks to the positively charged sides of the channel.
Sodiums waters of hydration do not align with the selectivity filter so they do not strip the waters off
Sodium does not form waters of hydration so the selectivity filter does not recognize it.
Sodium is too small to pass through the channel so it diffuses through without a channel.

Lethal injections contain potassium chloride which works to stop the heart. Why is this an effective method of euthinasia?
It causes Na gates to remain inactive which means it cannot return to resting membrane potential causing excessive action potentials which shock the heart until it stops working
It causes Na gates to remain inactive which means it cannot return to resting membrane potential causing cessation of action potentials making the heart unable to pump
It causes K gates to remain open which means it cannot return to resting membrane potential causing excessive action potentials which shock the heart until it stops working
It causes K gates to remain open which means it cannot return to resting membrane potential causing cessation of action potentials making the heart unable to pump
It causes more potassium to be in the extracellular fluid making it harder for the cell to reach threshold so there is less action potentials being reached and thus the heart stops beating

Patent ductus arteriosus is a heart defect in the pulmonary artery that carries oxygen-poor blood to the lungs and the artery that carries oxygen-rich blood to the rest of your body. How would this condition affect the rest of the body in terms of membrane potential?
It depolarizes the membrane because there is no Na/K pump action because there is a lack of ATP
It hyperpolarizes the membrane because there is an influx of K making it harder to reach threshold
It causes the threshold to increase meaning it takes a bigger stimulus and makes it harder for oxygen to be transported throughout the body
It repolarizes the membrane before there is an action potential, so the body cannot effectively carry oxygen throughout the body
It would not affect membrane potentials, it would have an effect on hemoglobin binding causing a shift to prefer myoglobin.

Cystic Fibrosis is a disease caused by a mutation in which of the following types of channels?
Mechanically gated chloride channels
Ligand gated calcium channels
Ligand gated chloride channels
Voltage gated chloride channels
Voltage gated calcium channels

The ion with the biggest effect on the resting membrane potential is the ion with which of the following?
The largest driving force
The most voltage gated channels
The highest permeability
The least net movement
The greatest negative charge

A patient presents at a clinic you are rotating at during your OMS III year with acute hyperkalemia. Which of the following is a true statement regarding the physiology of this condition?
There is more potassium in the extracellular environment, so the driving force of the ion has gone up.
There is more potassium in the extracellular environment, so the membrane potential will depolarize
There is more potassium in the extracellular environment, so the membrane potential will hyperpolarize
There is less potassium in the extracellular environment, so the membrane potential will depolarize
The potassium concentrations has remained the same, but the membrane will depolarize

Which of the following locations has voltage gated calcium channels?
Finger tips
Synaptic Terminals
Axons
Dendrites
Axon Hillock

An unknown bacteria has the following equilibrium potentials for sodium and potassium (picture above). Membrane potential of this bacteria is -60. Given the values below, what is the driving force of potassium and would it flow in or out?

K+: -84

Na+: +68

24, flow outward
-24, flow inward
-128, flow outward
128, flow inward
-60, no net movement

Which of the following is true regarding the Sodium Potassium ATPase?
It pumps 3 Potassium in
It pumps 2 Sodium out
It is responsible for the gradients that allow glucose uptake in the small intestine
It is responsible for depolarization
It uses ATP to drive ions with their concentration gradients

Adrenoleukodystrophy is a rare hereditary metabolic disorder in which fats accumulate in the brain causing demyelination of nerves. Which of the following symptoms would you expect to see in a patient suffering from adrenoleukodystrophy?
Decreased satiety
Hypoglycemia
Spasticity
Frequent fainting
Weight gain

In reference to the diagram below, which segment is dominated by the opening of ligand gated sodium channels?
1
2
3
5
6

You are completing your residency as a family practitioner and one of your colleagues asks for a refresher on coding for stimulus intensity. You explain that the intensity of the stimulus is impacted through which of the following?
The amplitude
The length of time it fires
The strength of the action potential
The frequency
The conduction speed

Which of the following descriptive factors can be used to describe an action potential?
Decremental
Summation possible
Reversible
Self propagating
Inhibitory or Excitatory

While rotating in the ED your preceptor notices a patient come in with a superficial laceration to their forearm and instructs you to suture the wound. Before you begin suturing you inform your patient you are going to inject Lidocaine (a local anesthetic) into the area around the laceration to numb the area. If you want to really be a know-it-all you can explain that the lidocaine will inhibit which of the following from working?
Ligand gated sodium channels
Voltage gated sodium channels
Ligand gated potassium channels
Voltage gated potassium channels
Voo doo

Tristan drinks Diet Coke at all hours of the day averaging about a twelve pack daily. Lately he has been having headaches and drinking more because he believes they are caffeine related headaches. What problem is he truly having?
The caffeine is causing a blockage of acetylcholinesterase which is causing his neuromuscular junctions to fire constantly causing the headaches
Diet Coke contains MSG which causes a short-term reaction that results in headaches
An ingredient in the Diet Coke activates NMDA receptors and turns phenylalanine into a toxic intermediate causing headaches
Diet Coke contains a lot of sugar and the headache he is getting is from his body becoming used to that amount of sugar and then using it quickly
The Diet Coke opens calcium channels that then cause a cascade of reactions, these reactions running all at once cause his head to hurt as it goes into overdrive

What is the correct order of the sequence of events of action potential propagation that are listed below?

Neurotransmitters bind to postsynaptic receptor

Voltage gated Ca2+ channels open,

Neurotransmitters diffuse into synaptic cleft

Na+ channels open in postsynaptic neuron,

Threshold is reached initiating a new action potential

Neurotransmitter is degraded by enzymes in the synaptic cleft,

Ca2+ influx

Synaptic vesicles fuse with membrane,

Action potential reaches the presynaptic terminal

9, 2, 7, 5, 6, 8, 3, 1, 4
5, 6, 9, 2, 7, 8, 3, 1, 4
5, 9, 7, 2, 6, 1, 8, 3, 4
9, 2, 7, 8, 3, 1, 4, 5, 6
9, 4, 2, 7, 8, 1, 3, 6, 5

Sinemet (Carbidopa-levodopa) is a medication used to treat the symptoms of parkinson’s disease. How does this medication work?
It increases dopamine production
It decreases dopamine breakdown
It increases dopamine release
It inhibits MAO
It inhibits COMT

The synapse responsible for a sodium channel causes a graded potential could be described as which of the following?
Chemical Excitatory Ionotropic
Chemical Excitatory Metabotropic
Electrical Inhibitory Ionotropic
Chemical Inhibitory Metabotropic
Electrical Excitatory Ionotropic

You recently discover that one of your grandparents has been diagnosed with Alzheimer’s Disease. Knowing that Glutamate excitotoxicity has been found to be correlated with this disease, what else may also be dysfunctional?
Tripartite/astrocytes
Inability for calcium influx
Phospholipase C
Adenylyl Cyclase
Nitric oxide synthase

Why are blood vessels able to contract strongly and not contract in a ripple?
They do not require an action potential
They release an excess of calcium so they contract very fast
They do not have synaptic clefts to get across
Neurotransmitters are always firing
Their nerves are highly myelinated

When we are hot, our body sends a signal to our sweat glands to release their contents which then evaporates on our skin to help cool us down. Which of the following explains how the sweat gland functions?
The preganglionic neuron releases acetylcholine which then activates a nicotinic receptor that releases acetylcholine onto a muscarinic receptor that releases acetylcholine to activate the sweat gland
The preganglionic neuron releases acetylcholine which then activates a muscarinic receptor that releases acetylcholine onto a nicotinic receptor that releases acetylcholine to activate the sweat gland
The preganglionic neuron releases norepinephrine which then activates a nicotinic receptor that releases acetylcholine onto a muscarinic receptor that releases acetylcholine to activate the sweat gland
The preganglionic neuron releases norepinephrine which then activates a muscarinic receptor that releases acetylcholine onto a muscarinic receptor that releases acetylcholine to activate the sweat gland
The preganglionic neuron releases acetylcholine which then activates a nicotinic receptor that releases norepinephrine onto a muscarinic receptor that releases acetylcholine to activate the sweat gland

Mike is college basketball player. He goes in for a checkup and finds that his heart rate is resting at about 45 beats per minute. He had just learned that 60-100 beats per minute is normal and is concerned about his low rate. You tell him that…
Because of his athletic build, he doesn’t need his heart to pump as hard to profuse his tissues
Because of his muscle tone, he has an excess of myoglobin which is able to release O2 to his tissues so his heart doesn’t need to pump as hard
He has an increased vagal tone meaning that it takes more sympathetic stimulation to raise his heart rate
He has a decreased vagal tone meaning that it takes more sympathetic stimulation to raise his heart rate
He has a decreased vagal tone meaning that it takes more parasympathetic stimulation to raise his heart rate

Which of the following is true in regards to the sympathetic nervous system?
It is predominately activated in times of minimal stress
The preganglionic fibers enter the grey rami communicates before exiting the white
Its preganglionic neurons predominately come from the brain stem
Its postganglionic neurons only release norepinephrine
It has long postganglionic neurons

While doing your family medicine rotation 3rd year you notice a patient with who has been diagnosed with both high blood pressure and asthma. It looks like your preceptor may not have noticed he was diagnosed with both because when you look at his chart he has been prescribed which of the following medications?
β-1 Blocker
Mixed β Blocker
β-2 Agonist
Muscarinic Agonist
α-1 agonist

A patient recently had to have both his adrenal glands removed due to adrenal cell carcinoma. Which of the following activities would it be most difficult for him to achieve now?
Bronchiole smooth muscle constriction
Mydriasis
Increased GI Motility
Increased heart rate and contraction
Thermoregulation due to sweating

Which of the following is true regarding the autonomic tone of blood vessels?
Supplied only by sympathetic
Supplied only by parasympathetic
Mixture of both but dominated by sympathetic
Mixture of both but dominated by parasympathetic
Does not have autonomic tone

Assume for the point of this question that the heart follows the concept of the Denervation in the same principle as blood vessels. After the heart has been completely denervated the heart rate will increase to that of the sinoatrial node which is 80-100. After one week a patient is given an epinephrine injection due to an allergic reaction What will the effect on the patient’s heart rate be?
There will be no effect since denervation means the removal of all receptors
The heart rate will decrease slightly
The heart rate will decrease dramatically
The heart rate will increase slightly
The heart rate will increase dramatically

Which of the following below correctly matches the receptor with its G protein/mechanism of action?
Alpha 1, Gi
Beta 1, Gq
Beta 2, Gs
Nicotinic, Gs
Muscarinic 2, Gq

Which of the following below correctly matches the reflex with its stimulus and response?
Urination – distention of the bladder causes contraction of the internal urinary sphincter
Coughing – irritation of the respiratory tract causes explosive inhalation of air
Baroreceptor – sudden rise in carotid blood pressure causes reduction in heart rate and force of contraction
Cardioacceleratory – sudden decline in carotid blood pressure causes reduction in heart rate and force of contraction
Pupillary – bright light shinning in the eyes causes constriction of pupils in both eyes

The preganglionic axons that synapse with collateral ganglia of the abdominopelvic cavity are most specifically
Spinal nerves
Splanchnic Nerves
Axons to the adrenal medulla
Sympathetic chain ganglia
Parasympathetic chain ganglia

You are rotating in your OMS III year with a neurologist that asks you about your knowledge of preganglionic axons. You tell him that they all communicate with the neurotransmitter:
Norepinephrine
Epinephrine
Calcium
Acetylcholine
Nicotine

Raynaud’s Phenomenon is a condition where cold activates the sympathetic nervous system and results in a scenario of excessive vasoconstriction. This is most commonly seen in the hands, feet, ears, nose, and other extremities. What would be the most effective medication to use to treat such a condition?
Beta Blocker
NSAIDS
Alpha Blocker
Alpha/Beta Blocker
Muscle Relaxer

Alpha 2 receptors differ from the other receptors in the adrenergic class in which it belongs. Because of this variation, they prevent excessive stimulation so that you do not have a heart attack each time you are scared. They can perform this life saving response because when Alpha 2 receptors bind norepinephrine
The preganglionic neuron releases acetylcholine, exciting the postganglionic neuron
The preganglionic neuron hyperpolarizes, decreasing acetylcholine release and postganglionic neuron activity.
The preganglionic neuron depolarizes, increasing acetylcholine release and postganglionic activity
The cell acts with positive feedback and promotes excessive sympathetic output
There is no change in the preganglionic neuron, so the postganglionic neuron functions as normal

When doing a biopsy of your diabetic patient’s pancreas, you discover that your patient has cancer in their β-cells. You then get a measurement of her C-peptide and your preceptor asks why that is a logical next step. You tell him that:
It will let you know if it is benign or malignant
It will determine how much insulin she is producing
It will determine if they are injecting the correct amount of insulin
It will allow you to see if and where the cancer has metastasized to
It will determine if the pancreas is functioning as it should to help with digestion

Your friend Tiffany was only half listening about leptin and is confused as to why it couldn’t be used independently to treat obesity in humans. Which of the following explains why this would not be an effective obesity treatment for humans?
Leptin is only found in mice
Leptin alone couldn’t work, it would have to be used in conjunction with peptide Y which has not been purified and isolated
Leptin is already secreted, its signal is ignored by individuals and eventually they become leptin insensitive
Leptin is already secreted, but it is less efficient when there is more adipose tissue
Leptin is only released when exercising, so giving it to obese patients would not be effective unless they are active.

After running a routine physical and blood tests on a patient, they begin to freak out because their blood glucose level is 135! They are very healthy, non obiese 35 year old male, and have no history of diabetes in their family. What is the most likely cause of the high blood glucose levels?
They may be pregnant and developed gestational diabetes
They have developed a mutation and have started to become a type 1 diabetic
They are so sensitive and sweet to other people they just have a normally elevated blood glucose level
They drink too much diet soda with aspartame which is known to raise blood glucose levels
They didn’t listen like most people and ate 2 hours before their exam

Martha tells you that she has been doing the keto diet where she eats fewer than 20 grams of carbohydrates a day. While on this diet, what does her red blood cells use for fuel?
They will switch to using ketone bodies to run glycolysis
They will function on the 20 grams of carbohydrates that she consumes per day
They will rely more heavily on gluconeogenesis to create glucose
They will switch to using fats to create energy through β-oxidation
They will break down amino acids from the increased protein she is consuming.

Epinephrine is a more powerful regulator of glycogen synthesis/breakdown than glucagon, which is why it needs two different receptors on the liver. When epinephrine bings to a Beta 2 receptor on the liver, which G protein will it be?
Gs
Gi
Gq
Gp
Gc

The conversion of Fructose-6-Phosphate to Fructose-1,6-Bisphosphate is a highly regulated part of glycolysis. Which of the following is an agonist of this step?
cAMP
ATP
Fructose-2,6-bisphosphate
Fructose-1,6-bisphosphate
Citrate

Which of the following pairs would show a similar Lineweaver-Burke graph?
Hexokinase, GLUT 2
Glucokinase, GLUT 2
Hexokinase, GLUT 4
Glucokinase, GLUT 4
Glucokinase, SGLT

Which step in glycolysis is unable to proceed if there is a shortage of NAD+?
Step 1 – glucose → glucose-6-phosphate
Step 3 – fructose-6-phosphate → fructose-2,6-bisphosphate
Step 6 – glyceraldehyde-3-phosphate → 1,3-bisphosphoglycerate
Step 9 – 2-phosphoglycerate → phosphoenolpyruvate
Step 10 – phosphoenolpyruvate → pyruvate

Veronica suffers from anorexia nervosa causing her to have low vitamin B1 levels. Which of the following coenzymes related to the pyruvate dehydrogenase complex would she have trouble synthesizing?
TPP
Lipoate
FAD
NAD+
CoA

Which of the following regulators when present will decrease or inhibit the formation of Acetyl CoA from Pyruvate by activating PDC Kinase?
Calcium
ADP
Pyruvate
NADH
NAD+

Fumaric aciduria is a rare autosomal recessive metabolic disorder characterized by a deficiency of the enzyme fumarate hydratase (fumarase), which causes a deficiency of malate. What effect would this have on the production of ATP?
Fumaric aciduria is a rare autosomal recessive metabolic disorder characterized by a deficiency of the enzyme fumarate hydratase (fumarase), which causes a deficiency of malate. What effect would this have on the production of ATP?
This would cause a build up of oxaloacetate in the mitochondria
This would cause glycolysis to not be able to occur in the mitochondria
This would cause glycolysis to not be able to occur in the cytoplasm
This would cause the electron transport chain to collapse
This would cause oxaloacetate to be converted to malate at a slower rate

Isocitrate dehydrogenase is the TCA enzyme responsible for the oxidative decarboxylation of Isocitrate to α-ketoglutarate. In IDH mutations, mutant isocitrate dehydrogenase additionally reduces α-ketoglutarate to D-2-hydroxyglutarate (2-DHG). How does this mutant TCA oncometabolite compromise cellular integrity that potentially leads to cancer?
2-DHG through feedback inhibition ceases the enzymatic activity of Isocitrate dehydrogenase.
2-DHG competitively inhibits α-ketoglutarate dependent dioxygenases.
2-DHG allosterically activates succinate dehydrogenase to produce metastatic levels of α-ketoglutarate.
2-DHG irreversibly activates α-ketoglutarate dependent dioxygenases that generate onco-enzymatic proteins that promote unregulated cell proliferation.

The legend of vampires is believed to have stemmed from individuals who had the disease porphyria which can often include symptoms such as sensitivity to sunlight which can be treated with exogenous blood ingestion. Deficiency in which TCA cycle intermediate can lead to porphyria?
Oxaloacetate
ɑ-ketoglutarate
Citrate
Fumarate
Succinyl-CoA

Which of the following enzymes reduce a vitamin B2 derivative through their enzymatic activity in the TCA cycle?
Malate dehydrogenase
Fumarase
Isocitrate dehydrogenase
Succinate dehydrogenase
Aconitase

Which of the following below contains the three enzymes that produce NADH during the TCA Cycle?
Isocitrate dehydrogenase, ɑ-ketoglutarate dehydrogenase, Succinyl-CoA synthase
Succinate dehydrogenase, Isocitrate dehydrogenase, Succinyl-CoA synthase
Malate dehydrogenase, Isocitrate dehydrogenase, Succinate dehydrogenase
Malate dehydrogenase, Isocitrate dehydrogenase, ɑ-ketoglutarate dehydrogenase
Malate dehydrogenase, ɑ-ketoglutarate dehydrogenase, succinate Dehydrogenase

In the early 1960’s the benefits of Vitamin E were discovered and doctors started prescribing it as a pill to virtually everyone. Which of the following explains why this was not effective in preventing many of the diseases that natural vitamin E had been seen to prevent?
Most of the patients had scurvy so the were unable to turn the free radicals into the aqueous form and therefore unable to rid the body of them.
Vitamin E supplements were only one form of tocopherols and when they were taking the pills, they were depleting the other forms thus unable to oxidize in other ways.
Vitamin E must be taken as a part of a multivitamin or else it depletes the other vitamins and causes more harm than good
Even if they had the increased Vitamin E, they would still have the same amount of Glutathione so they would be unable to oxidize the radicals.
In larger doses, vitamin E actually causes more free radicals to form.

Molly’s pediatrician told her that she could give acetaminophen to her 6 month old for fevers. She didn’t have any acetaminophen so she gave her baby baby aspirin which she thought would be okay because it had the word baby in the name. Which of the following explains what would happen?
Her baby’s fever would decrease because aspirin and acetaminophen are interchangeable and you can use them at alternating times
Her baby’s fever would decrease because the aspirin would work to block the COX1 and COX2 pathways
Her baby’s fever would decrease because the aspirin would work to block the 5-LOX pathway
Her baby’s fever would spike because aspirin would uncouple the ETC causing heat instead of ATP to be formed.
Her baby would die because aspirin would decrease the infant’s ability to clot so they would bleed out.

In most infections (especially bacterial), neutrophils are characterized as the first responders as they often the first leukocyte to be elevated and attempt to resolve the infection. Neutrophils are also characterized as phagocytes which means they ingest their targets and then fuse them with lysosome to degrade them. Phagocytes also implement reactive oxygen species is order to damage and destroy their ingested targets. Which NADPH oxidase (NOX) enzyme is found in these types of cells?
NOX 1
NOX 2
NOX 3
NOX 4
NOX 5

Nitric oxide is created in endothelial cells of blood vessels when acetylcholine binds to its G protein coupled receptor. What enzyme will the G alpha subunit activate after acetylcholine has bound?
Adenylyl Cyclase
Guanylyl Cyclase
Phospholipase C
Phosphodiesterase
Nitric Oxide Synthase

Kevin wanted to look cool when he went to his first rave festival, so he took amphetamines that he got from the sketchy looking man in the bathroom line. Unfortunately they were laced with MPP+ and Kevin woke up confused in the hospital with tremors in his hand, stiff muscles, and feeling very fatigued. Which of the following explains his symptoms?
The MPP+ caused complex I of ETC to not work
The MPP+ caused complex II of ETC to not work
The MPP+ caused complex III of ETC to not work
The MPP+ caused cytochrome C of ETC to not work
The MPP+ caused Coenzyme Q of ETC to not work

Which of the following is required to produce additional NADPH in order to fuel Glutathione Reductase to reduce glutathione?
NAD+
FAD
Glucose-6-phosphate
Ribose-6-phosphate
Selenium

People suffering from Crohn Disease are frequently deficient in many vitamins including Selenium due to their inability to absorb vitamins despite their consumption. Which of the following would be affected by a selenium deficiency?
Glutathione
Superoxide dismutase I
Superoxide dismutase II
Catalase
Glutathione-Peroxidase

People with hemolytic anemia have problems reducing glutathione. Hemolytic anemia results in the rupture of red blood cells. Which of the following would NOT be a problem for people with this disease?
They are not able to regenerate NADPH
They get a buildup of H2O2 in their cells
They get a buildup of hydroxyl radicals
They get a buildup of NADPH
They have a reduced number of RBCs

Which of the following would be an example of a Hormetic response to stressors?
Membrane distortion
Mitochondrial Dysfunction
ROS production
Differentiation
Inflammation

In the very young and the elderly, it is common to be deficient in the various B vitamins. If one of these individuals is deficient in both cobalamin and pyroxidine, they will get a toxic buildup of which product?
Methyl Malonyl CoA
Uric Acid
Hydrogen Peroxide
Glutathione
Homocysteine

All of the following Gluconeogenic mechanisms are stimulated by increased levels of Glucagon, except for:
Phosphorylated Pyruvate Kinase
Increased PEPCK gene transcription
Increased hepatic Fructose 2,6-bisphosphate
Increased cAMP
Phosphorylated (PFK-2/FBP-2)

Skipping her normal balanced breakfast, Tammy was beginning to feel the burn one hour in to her midmorning marathon in downtown Chicago. Which of the following occurs during Glycogenolysis to maintain Tammy’s blood glucose levels and fuel exercising skeletal muscle during this event?
Phosphorylation of Glycogen Phosphorylase by PKA
Phosphorylation of Glycogen Synthase by Glycogen Phosphorylase
Phosphorylation of Glycogen Phosphorylase by Phosphorylase Kinase
Phosphorylation of Phosphorylase Kinase by Glycogen Phosphorylase
Phosphorylation of Glycogen Synthase by Phosphorylase Kinase

A point mutation in glycogenin causes a stop codon to form where a tyrosine residue should be. Which of the following would you expect to see in a patient with this mutation?
Inability to convert glucose-6P to glucose 1P
Inability to convert glucose-1P to glucose-6P
Inability to form glucose chains of glycogen
Inability to form the branch points of glycogen
Inability to break the glucose free from the glycogen chains.

A mutation in PFKFB genes 1-4 on chromosome X leads to non-functional PFK-2/FBP-2 enzyme. What effect does this have on metabolism?
Inability to carry out glycolysis because fructose-1,6-bisphosphate cannot be synthesized from fructose-6-phosphate.
Inability to metabolize fructose.
Inability to carry out glycolysis because fructose-2,6-bisphosphate is necessary for the activity of PFK-1/FBPase-1
Simultaneous gluconeogenesis and glycolysis

Which of the following is most characteristic of Glycolysis?
Increased FBP-1 activity
Phosphorylated (PFK-2/FBP-2) enzyme
PFK-1 product modulating Pyruvate Kinase activity
Increased FBP-2 activity
Decreased PFK-1 activity

In order to test the efficacy of a novel drug therapy on diseased cardiomyocytes, you first want to determine if any unwanted side-effects occur in otherwise healthy cardiac cells. Fibroblasts donated to your research clinic from a healthy 30 year old male could be reprogrammed into iPS cells using which of the following combinations of transcription factors?
c-Myc, Nanog, Oct4
Oct4, Sox2, c-Myc
Sox2, Oct4, Axin
Wnt, Oct4, Klf4
Klf4, Sox2, Oct4

A patient comes in complaining of pain in their lower abdomen. Blood tests are ordered and show an increase in white blood cells. A CT scan reveals a tumor in their small intestine. Which of the following enzymes involved in the WNT pathway would you expect to see a mutation in?
Frizzled
Groucho
Axin
β-cantenin
Slug

Which of the following is a difference between necrosis and apoptosis?
Apoptosis is cell death whereas necrosis is cell resurrection
Apoptosis occurs with individual cells whereas necrosis occurs with multiple cells
Necrosis requires a signal whereas apoptosis occurs on its own
Necrosis is programmed cell death whereas apoptosis occurs because of injury or disease
Necrosis occurs because of stress whereas apoptosis is a natural part of the cell cycle

Following an MI there is an increase in neutrophils that can be seen in tissue samples of myocardial tissue, which of the following explain this?
An MI is due to an infection in the heart and these cells are trying to rid the body of the infection
An MI causes death of myocardial tissues via apoptosis which causes inflammation as the cells rupture
An MI causes death of myocardial tissues via necrosis which causes inflammation as the cells rupture
This would only be seen in patients with an autoimmune disease in which their neutrophils attack healthy cells
This would not occur.

After a routine follow-up visit, your patient presents you with information regarding a new stem cell therapy for DM Type I that they saw on Doctor Oz using earlobe cartilage as a stem cell precursor. As a DM Type I patient, they intrigued and clearly fixated on this new therapy as a way to cure their life-long disease. As an osteopathic physician trained in bioethical practices and well-versed in current stem cell literature, you politely inform your patient that:
Only stem cell therapy derived from skin fibroblasts and driven to the iPS cell state by the core trio are considered legitimate therapies approved by the FDA for use in the U.S.
Although questionable, SC therapy derived from ear cartilage that undergoes the appropriate processing are FDA approved as the infancy of this therapy has not yet been proven as detrimental to patient health beyond a reasonable doubt.
The only stem cell-based products that are FDA-approved for use in the U.S. consist of hematopoietic progenitor cells derived from cord blood.
No form of stem cell-based products are FDA-approved as the infancy of this technology negates it from being a legitimate therapy until epidemiological methods have been used to compile and analyze the current data.

A tissue sample from an unknown skin lesion is analyzed microscopically and enzymatically to determine whether or not necrosis has taken place. Which of the following scenarios is indicative of necrosis and not apoptosis?
Immunofluorescence assay indicating phospholipid phosphatidylserine exposed on the outer leaflet of the cell membrane.
Free LDH present in the blood of the tissue sample.
Segmented and condensed nuclear chromatin.
Free IL-10 and TGF-β present in the blood of the tissue sample.

Your patient, a seasoned automotive mechanic, presents to your clinic with an abnormal growth on his forearm that occasionally bleeds and has persisted for the past 6 months. During the intake, he reveals to you that he has never felt the need to wear protective gloves while doing oil changes for the past 30 years. You biopsy the lesion and send it to pathology to rule out basal vs. squamous cell carcinoma. What abnormality in the internal cell death program would indicate that apoptosis has been compromised in this lesion?
Cytochrome-c occupies all of the available sites of Apaf-1, activating the protein.
p53, a tumor suppressor protein, binds to its response element within DNA and results in suppressed transcription of the target gene.
Bax embeds itself in the mitochondrial membrane and facilitates the release of cytochrome-c.
p53, a tumor suppressor protein, binds to its response element within DNA and induces transcription of the target gene.

A recent discovery by John B Gourdon and Shinya Yamanaka showed that mature cells can be reprogrammed to become pluripotent using a specific set of transcription factors that are able to upregulate and downregulate thousands of genes depending on their concentrations. Which of the following transcription factors is unable to reprogram cells by regulating epigenetics?
ct4
Sox2
Klf4
c-Myc
Nanog

Mesenchymal cells of the mesoderm are considered to be which of the following?
Totipotent
Pluripotent
Multipotent
Bipotent
Unipotent

The inner cell mass is considered to be pluripotent because it can become almost everything necessary to a developing embryo and future human. What is one structure that it can NOT become?
Brain
Epithelium of the respiratory tract
Anterior Pituitary Gland
Right Lobe of the Liver
Chorion
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Exam 3

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Welcome to your BECOM-1 Exam 3 (2018)

Many DNA-based diagnostic tests use a DNA polymerase from Thermus aquaticusa bacterium that can surface high temperatures. Compared with the DNA of bacteria that grow at 25ºC, the DNA of T. aquaticusis expected to have higher fraction of which of the following nucleotides?
Adenine and cytosine
Cytosine and Guanine
Adenine and Guanine
Cytosine and Thymine

Some nitrofurans form adducts with bases in DNA that cannot be repaired via the base-excision repair pathways. The adducts leads to distortions of the DNA double helix. The lesion is most likely repaired by which one of the following DNA repair pathways?
Homologous recombination repair
Mismatch repair
Nonhomologous end joint
Nucleotide-excision repair
Base-excision repair

A 48-year-old woman had endometrial cancer and undergoes a hysterectomy. Immunohistochemistry of tumor tissue reveals the presence of MLH1 and PMS2, but an absence of MSH2 and MSH6. Based on this finding, the most likely diagnosis is which of the following?
Cockayne syndrome
Hereditary breast and ovarian cancer syndrome
Lynch syndrome
MUTYH-associated polyposis

In DNA replication, DNA “unwinds” to form two template strands, the leading strand and the lagging strand. Which of the following statements about these strands is true?
Okazaki fragments are used to synthesize the leading strand of DNA.
The leading strand of DNA is synthesized continuously.
DNA polymerase can only synthesize DNA on the leading strand.
The lagging strand can only be synthesized once the leading strand has been completed.
The leading and lagging strand are synthesized by RNA polymerase.

A 69-year-old male patient with metastatic colon cancer receives treatment with a cocktail of chemotherapeutic drugs that contains irinotecan (inhibitor of topoisomerase). This drug inhibits which of the following processes?
Modification of histone tails
Pairing of complementary bases
Reading of bases in the major groove
Relaxation of supercoiled DNA
Ligation of Okazaki fragments

For a particular protein, the template strand contains the sequence 5’-ACCGT-3’. After transcription into mRNA, the RNA contains which of the following sequences?
5’-ACGGU-3’
5’-ACCGU-3’
5’-UGCCA-3’
5’-UGGCA-3’
5’-ACGGT-3’

Methylation at a promoter of a gene is most likely to result in which of the following?
Increase transcription by active recruitment of transcription factors and recruitment of histone acetyltransferases
Decreases transcription by physically impeding the binding of transcription factors and through the recruitment of histone acetyltransferases
Increase transcription by active recruitment of histone deacetylases
Decrease transcription by physically impeding the binding of transcription factors and through the recruitment of histone deacetylases
There is minimal impact on transcription resulting from methylation at promoters

It is common for large eukaryotic genomes to express more proteins than there are genes in the genome. Which mechanism best explains this phenomenon?
Promoters
Enhancers
Alternative splicing
Exon skipping
RNA editing

Which of these would lead to gene suppression?
Administration of a HDAC inhibitor
Addition of HAT activity to transcription factors
Deficiency in DNA methyltransferase
Methylation of CG islands
An increase in transcription factors

Mutations in DNA large distances from a structural gene can lead to over or under expression of that gene. Which of the following eukaryotic DNA control sequences does not need to be in a fixed location and is most responsible for high rates of transcription of particular genes?
Promoter
Promoter-proximal element
Enhancer
Operator
Splice donor site

Regulation of gene expression by thyroid hormones is mediated via thyroid hormone receptors. The receptors act as molecular switches in response to ligand binding. In the absence of ligand, how do thyroid hormone receptors function?
They are coupled with a corepressor complex containing HDAC, which halts transcription.
They are coupled with a corepressor complex lacking HDAC, which leads to cell proliferation.
They are coupled with coregulators that contain HDAC, which leads to cell proliferation.
They are coupled with coregulators that contain HAT, which halts transcription.
They are coupled with coregulators that contain HAT, which leads to cell proliferation

Which of the following is the enzyme involved in adding an amino acid to the 3’ end of the tRNA?
ATP synthase
Aminoacyl tRNA synthetase
tRNA polymerase
RNA polymerase III
Aminoacyl mRNA synthetase

The genetic code derives its specificity through which of the following interactions
Hydrogen bonds and disulfide bonds that maintain the shape of the tRNAs
Complementary base pairing between amino acids and tRNA
Complementary base pairing between tRNA and mRNA
Ionic bonds between the small and large subunits pf the ribosome
Hydrogen bonding between the ribosomal subunits and the mRNA

Which of the following is most likely to occur when a ribosome encounters a UAG codon of an mRNA that derives from a normal non pathogenic allele?
Release factor binds` to UAG
Met is incorporated into the nascent peptides
The ribosomes binds to the signal recognition particle
The ribosome stalls the mRNA is degraded by nonsense-mediated decay

A 33-year-old patient presents to your office with fatigue, muscle weakness, and shortness of breath. You perform some blood work and notice a low red blood cell count and, as a result, high levels of Epo. You know that Epo should be signalling the Jak/STAT receptors for gene transcription, so you worry there may be an issue at the genomic and/or DNA level. If you know the protein sequence should code for an His (CAU, CAC) near the C terminus, what would you expect the template sequence to appear as? Note, the entire sequence is given below:
5’ CTACGATGATAACTGCAT 3’
5’ TCAATGTTCAGACCGCAT 3
5’ TTAATGTTCGGACCGCGT 3’
5’ TCAATGTCGGACCGCGT 3’
5’ TTAATGATCGAATCGCGT 3’

Many commonly used antibiotic drugs are able to target both eukaryotic and prokaryotic genetic machinery, but preferentially act on prokaryotic cellular structures. One such bacteriostatic drug works by binding to the aminoacyl site of the 30s ribosomal subunit, preventing translation of mRNA templates into amino acids. This mechanism most accurately describes which drug?
Tetracyclines
Aminoglycosides
Macrolides
Clindamycin
PARP inhibitors

Diphtheria toxin is an extremely potent poison derived from Corynebacterium diphtheriae bacteria, and ultimately inhibits protein synthesis by which mechanism?
Inactivation of peptidyl transferase
Inactivation of eIF2
Inhibition of the ATP hydrolysis step of eIF4’s helicase activity
Inactivation of eEF2
Inhibition of the GTP hydrolysis step of eIF4’s helicase activity

Which of the following would result in formation of a novel protein?
Gene amplification of a proto-oncogene
Coding mutation of an oncogene
Regulatory mutation of an oncogene
Translocation of a proto-oncogene
Coding mutation of a proto-oncogene

A drug targeting inhibition of which of the following would NOT assist in ceasing the cell cycle, causing apoptosis:
RTKs
P21
CDK2-E
CDK2-A
CDK1-A

Your 42 year old, female patient presents with chest pain and difficulty breathing. Upon taking a history, you find she has a family history of breast cancer. Your exam shows potential breast lumps in the upper-right, lateral quadrant of her left breast. Thinking back to what you learned from Dr. Ree regarding gene mutation, you contemplate the following possibilities for your patient’s condition:
Von Hippel-Lindau Syndrome
Lynch syndrome
Familial adenomatous polyposis
Retinoblastoma
Li-Fraummeni syndrome

Which of these results from DNA damage?
Inactive Rb/E2F complex, therefore decreased nuclear transcription
Phosphorylation of MDM2, therefore decreased nuclear transcription
Active Rb/E2F complex, therefore recruitment of DNA repair enzymes
Decrease in p21, therefore recruitment of DNA repair enzymes
Activation of Bax via p53, therefore an increase in nuclear transcription

What roles in regulating the intrinsic pathway of apoptosis are played by the Bcl-2 protein family members Bax and Bcl-2?
Bax inhibits apoptosis while Bcl-2 stimulates apoptosis.
Bax stimulates apoptosis while Bcl-2 inhibits apoptosis.
Both Bax and Bcl-2 inhibit apoptosis.
Both Bax and Bcl-2 stimulate apoptosis.
Bax activates Bcl-2, which stimulates apoptosis.

Loss of both p53 protein alleles is found in >50% of human tumors. Which one of the following is a function of the p53 protein?
Halting replication in cells that have suffered DNA damage
Targeting repaired cells to undergo apoptosis
Stimulating cyclin production
Simulating CDK production
Stimulating phosphorylation of Rb

Consider a woman who is a known heterozygous carrier of the mutant gene that causes Hemophilia A. She is considering trying to conceive her first child. Her husband is not a carrier of the disease. What is the probability that her first born child will exhibit symptoms of Hemophilia A?
None of her children will have the disease, they could only be carriers of the disease.
¼ chance
¼ chance
¾ chance
All of her children will have the disease

Which is true regarding X-chromosome inactivation?
X-inactivation is most likely to occur in the maternal X than the paternal X chromosome.
Expression of X-chromosome inactivation occurs at a 50:50 ratio in females.
Barr bodies are found in both male and female dividing somatic cells.
X-inactivation usually leads to death in females during the prenatal period and normal function in males.
Once random X-chromosome inactivation occurs, it is permanent in all descendants of that cell.

The crossing of an unaffected male and a heterozygous recessive carrier of an X-linked recessive disorder could lead to which of the following?
All unaffected daughters, 50% sons affected
50% daughters affected, 50% sons affected
50% daughters affected, all unaffected sons
25% daughters affected, all sons affected
All children unaffected

In which instance could two affected parents produce unaffected children for an autosomal dominant disease?
Both heterozygous parents
Homozygous dominant mother, heterozygous father
Homozygous dominant mother, homozygous recessive father
Heterozygous mother, homozygous dominant father
Both homozygous recessive parents

Rodney was diagnosed with Xeroderma pigmentosum (XP) at a very young age. Xeroderma pigmentosum is a rare disease caused by mutation in genes that are involved in repairing damaged DNA. How did Rodney most likely inherit this disease?
His parents, who met at random, were both heterozygous carriers of the mutation that causes XP.
His parents are first cousins, and they were both recessive carriers of the mutation that causes XP.
His parents, who met at random, had a mosaic mutation for XP that occured prior to conception of Rodney.
His parents are first cousins, and they were both homozygous dominant for the XP allele.
His parents are first cousins. His mother is homozygous recessive for the XP mutation; his father is homozygous dominant for the XP allele.

A baby was born with syndactyly (webbing between her fingers). The doctor stated that this minor defect can be easily corrected surgically. What is the embryologic basis of syndactyly?
Type III symmelia occurred during development, leading to fused fingers.
A HOX mutation most likely caused the fingers to fuse during development.
A defect in apoptosis resulted in the webbing between fingers to break down properly.
The baby is part labrador retriever. She should be AKC registered for her unique development.
A premature AER secretion of FGF10 at the distal limb bud

Early on, the limb buds receive vascular supply from which of the following arteries?
Primary axial artery, which does not form an arterial network until after skeletal muscle formation
Dorsal intersegmental artery, which forms a vascular network prior to skeletal muscle formation
Aortic sac, which does not form a vascular network until after skeletal muscle formation
Primary axial artery, which forms an arterial network prior to skeletal muscle formation
Dorsal aorta, which does not form an arterial network until after skeletal muscle formation

Why do we care about fruit flies?
Fruit flies have translocation of body parts as a result of overexpression of the HOXD13 gene. This helps us understand amelia in humans.
The HOX genes, a gene shared by Drosophila and humans, determine the basic body plan.
Fruit flies have mutations that arise from the apical epidermal ridge, similar to mutations found in humans.
Fruit flies carry p53, so they are helpful in understanding the regulation of the cell cycle.
Dr. Ree likes them, so they are important.

Cartilage serves as a template for the development of skeletal bones. Limb buds grow from proliferation of which embryonic origin?
Mesenchymal primordia
Surface ectoderm
Endoderm
Intermediate mesoderm
Neuroectoderm

If a leg develops only to the knee, what axis of development was interrupted during embryological development?
Dorsoventral
Anteroposterior
Proximodistal
Craniocaudal
Rostrocaudal

Which of the following occurs first in fetal development?
4th metatarsal
3rd carpal bone
Ulna
Tibia
Humerus

The arrow in the CT scan above indicates which of these findings?

Abnormal findings, compression fracture of the vertebral arch
Normal findings, thoracic spinal cord enlargement
Normal findings, unfused neural arch in a child
Abnormal findings, osteoporotic costal facets
Normal findings, unfused neurocentral joint in a child

Spina bifida is a result of which structure failing to fuse?
Spinal cord
Vertebral arch
Dura mater
Vertebral body
Arachnoid mater

The cranium, mandible, vertebral column, ribs, and sternum are derived from which of the following?
Myotome
Dermatome
Sclerotome
Dermomyotome
Mesenchyme

What developmental process has occurred in a case of acrania?
Failure of the cranial end of the neural tube to close
Significant fusion of cranial sutures
Failure to develop a neurocranium
Failure of neural crest cells to develop the viscerocranium
Early ossification of the 1st pharyngeal arch and temporal bones

The T3 vertebrae is formed by which embryological precursors?
T3 loose mesenchymal cells and T4 dense mesenchymal cells
T3 loose mesenchymal cells and T4 loose mesenchymal cells
T3 dense mesenchymal cells and T4 dense mesenchymal cells
T3 dense mesenchymal cells and T4 loose mesenchymal cells
Strong independent T3 mesenchymal cells that don’t need no man

What is the difference between a motor end plate potential and an action potential at the neuromuscular junction?
The motor end plate is ligand-gated; the action potential is ligand-gated.
The motor end plate is ligand-gated; the action potential is voltage-gated.
The motor end plate is voltage-gated; the action potential is ligand-gated.
The motor end plate is voltage-gated; the action potential is voltage-gated.
The motor end plate has no potential; the action potential generates all of the reactions in the neuromuscular junction.

Exposure of Ryanodine receptors to high concentrations of insecticides completely disable the RYR1 channel. What effect does this have on contraction?
Paralysis of skeletal muscle
Paralysis of cardiac muscle
Decreased contraction of skeletal muscle
Decreased contraction of cardiac muscle
Increased contraction of cardiac muscle

Which of the following statements about the control of contraction in skeletal muscles is correct?
In skeletal muscles, contraction is initiated by a nerve impulse closing voltage-gated Ca2+ channels in the plasma membrane.
In skeletal muscles, contraction is initiated by a nerve impulse opening voltage-gated Ca2+ channels in the plasma membrane.
In skeletal muscles, contraction is initiated by a nerve impulse closing voltage-gated Ca2+ channels in the sarcoplasmic reticulum membrane.
In skeletal muscles, contraction is initiated by a nerve impulse opening voltage-gated Ca2+ channels in the sarcoplasmic reticulum membrane.
In skeletal muscles, contraction is initiated by phosphorylation of the myosin light chain.

Tetrodotoxin is a potent neurotoxin. Which site of action does this neurotoxin manipulate?
Acetylcholine release
Acetylcholinesterase
Endplate Potential
Muscle Contraction
Nerve action potential

Which of the following statements about the contraction of skeletal muscle is correct?
The power stroke of skeletal muscle contraction occurs when the myosin head hydrolyses ATP.
The power stroke of skeletal muscle contraction occurs when the myosin head binds ATP.
The power stroke of skeletal muscle contraction occurs when the myosin head releases ATP.
The power stroke of skeletal muscle contraction occurs when the myosin head releases ADP and Pi.
The power stroke of skeletal muscle contraction occurs when the actin binds ATP

Hypocalcemia leads to which of the following?
Increased excitability of motor neurons caused by hypocalcemia leads to tetany.
Increased excitability of motor neurons caused by hypocalcemia leads to twitch.
Decreased excitability of motor neurons caused by hypocalcemia lead to tetany.
Increased membrane potential caused by hypocalcemia leads to twitch.
Decreased membrane potential caused by hypocalcemia leads to twitch.

Gastrocnemius has a significantly shorter fiber length than tibialis anterior. Which of these best describes the relationship between these two muscles?
Velocity and force are independent of length.
Gastrocnemius has a greater velocity and less force than tibialis anterior.
Gastrocnemius has less velocity and a greater force than tibialis anterior.
Gastrocnemius has a greater velocity and a greater force than tibialis anterior.
Gastrocnemius has less velocity and less force than tibialis anterior.

Which type of muscle has a high mitochondrial density and consists of small fibers?
Slow-oxidative
Fast-Oxidative
Fast-Glycolytic
Very Fast-Glycolytic
Slow-Glycolytic

Which intracellular factor plays a role in skeletal muscle fatigue?
Increase in glycogen circulation
Decrease in ADP/ATP ratio
Inorganic phosphate concentration increase
Decrease in lactic acid
Increased electrolyte concentration within the cell

Cross Bridging is influenced by which of these?
Velocity of contraction
Muscle fiber recruitment
Force production
A & C
All of the above

Slow-oxidative muscle fibers include the recruitment of which of the following?
Type Ia
Type I fibers
Type IIa fibers
Type IIx fibers
Type IIb fibers

As force is increased, what happens to the velocity of contraction in skeletal and smooth muscle?
Velocity increases in both skeletal and smooth muscle as force is increased.
Velocity increases in skeletal muscle, but decreases in smooth muscle when force is increased.
Velocity decreases in skeletal muscle, but increases in smooth muscle when force is increased.
Velocity decreases in both skeletal and smooth muscle as force is increased.
Velocity is independent of force in smooth muscle, but decreases in skeletal muscle when force is increased.

Which of the following statements about smooth muscle contraction is CORRECT?
A Ca2+-calmodulin complex activates the phosphatase that causes contraction of smooth muscle.
Unlike striated muscle, contraction of smooth muscle cells occurs when Ca2+ levels fall.
Dephosphorylation of a myosin light chain allows actin-myosin binding in smooth muscle.
Phosphorylation of an actin filament allows actin-myosin binding in smooth muscle.
Phosphorylation of a myosin light chain allows actin-myosin binding in smooth muscle.

Edelfosine, a PLC antagonist, inhibits the release of stored cellular calcium via the IP3 pathway. In a multi-unit smooth muscle cell exposed to a similar agent, by what mechanism would the muscle cell rely on to increase cytosolic calcium levels?
Passive influx of calcium through Ca+2/Na+ exchangers
Active influx of calcium through Ca+2 ATPase
Active release of calcium stored in the sarcoplasmic reticulum through Ca+2 ATPase
Calcium-induced release of calcium stored in the sarcoplasmic reticulum
Direct entry of calcium through gap junctions with neighboring cells

In smooth muscle cells, the modulation of strength for contraction is most directly related to which cellular mechanism?
The efficiency of the ATPase on the myosin head
The ratio of MLCK to MLCP in the cytosol
The amount of calmodulin available for troponin binding
The inherently high velocity of smooth muscle contraction
The ATP efficiency of the “latching” mechanism of myosin head