BECOM-1 Exam 3 (2019) Published on October 4, 2020 by ehudspeth Welcome to your BECOM-1 Exam 3 (2019) Which of the following correctly matches the term to the definition? Euchromatin: less densely packed, more accessible to transcription factors Euchromatin: more densely packed, more accessible to transcription factors Euchromatin: less densely packed, less accessible to transcription factors Euchromatin: more densely packed, less accessible to transcription factors Which of the following enzymes is responsible for replacing the RNA bases of the primer with DNA bases? Helicase Single Strand Binding Proteins (SSBPs) DNA Polymerase III DNA Polymerase I Primase Which eukaryotic DNA Polymerase is the “go to” for DNA repair? DNA Polymerase α DNA Polymerase β DNA Polymerase γ DNA Polymerase δ DNA Polymerase ε Doxorubicin is a chemotherapeutic agent used to treat a variety of cancers by interfering with which protein involved in DNA replication? DNA Polymerase family Helicase Single Strand Binding Proteins Topoisomerases Proliferating Cell nuclear Antigen (PCNA) How are the free 3’ end nucleotides protected from DNA repair proteins? They are degraded to prevent overhang and recognition Telomerase extends the 5’ end to match the 3’ end to avoid any overhang They loop back and invade a double stranded portion forming a T-loop A poly-adenine tail is added to protect them from DNA repair proteins binding A modified guanine cap is added to repel the repair proteins Which of the following single strand DNA repair mechanisms must occur during the S phase? Base Excision Repair Mismatch Repair Nucleotide Excision Repair Nonhomologous End Joining Homologous Recombination Repair Individuals with BRCA1 mutations have a 55%-65% chance of developing breast cancer in their lifetimes and BRCA2 mutations have a 45% chance of developing breast cancer. BRCA1 and BRCA2 are proteins involved in which DNA repair mechanism? Base Excision Repair Mismatch Repair Nucleotide Excision Repair Nonhomologous End Joining Homologous Recombination Repair A defect in which of the following proteins would lead to dysfunctional Nonhomologous End Joining? Artemis Helicases MLH1 and PMS2 PALB2 Poly-ADP-ribose-polymerase (PARP) Cordycepin is an adenosine analog derived from a caterpillar fungi. It is being researched for its potential use as an anti-inflammatory drug. Cordycepin prevents/shortens the formation of a poly-A tail. This reduces the efficiency of mRNA cleavage and early transcription termination is observed. This would thus result in the inability to transcribe inflammatory genes. Which of the following processes would be affected by a cordycepin anti-inflammatory drug? Intron splicing Orienting the ribosome on the mRNA Ribosomal recognition of mRNA Decreased methylation of DNA Inability to rearrange genes Apolipoprotein B-100 is a protein that is synthesised in the liver and is involved in the metabolism of lipids. This protein is also found in the intestines but the intestines are unable to metabolize lipids because the apolipoprotein-B has been truncated due to an RNA editing event. Which of the following changes would result in the trunctication of this protein? UAC→UAG UGU→UGG CAU→CAC AUG→AUA GAU→GAC Activation of which of the following would increase transcription? Histone acetyltransferase (HAT) Histone Deacetylase (HDAC) DNA Methyltransferase Repressor proteins on Silencers A heterodimer with an empty thyroid hormone receptor (TR) and retinoid X receptor (RXR) DNA Methylation occurs on which base? Adenine Guanine Cytosine Thymine Uracil A patient with Non-hodgkins Lymphoma presents with worsening of her cancer that appears to have become resistant to the Methotrexate she has been taking. Which of the following is the most probable reason for this? The patient has actually developed a second type of cancer during the treatment The gene segment that codes for dihydrofolate reductase has gone through amplification to produce hundreds of copies of the gene The methotrexate has caused increased methylation of the genome leading to increased euchromatin around the dihydrofolate reductase gene Methotrexate has rendered HDAC’s ineffective so there is constant transcription of the dihydrofolate reductase gene Methotrexate binds to the silencer sequences in DNA thus losing the ability to silence various parts of the genome Activation of which of the following DNA response elements would lead to a decrease in Phosphoenol Pyruvate Carboxykinase (PEPCK)? Glucagon cAMP Thyroid Insulin Epinephrine How is it possible that the human genome contains 22,000 genes but is able to make over 100,000 different polypeptides? miRNAs can alter the final amino acid code of an mRNA to create different polypeptides Alternative splicing of the DNA can lead to different mRNAs HATs and HDACs control which genes are active in which tissues which allow different tissues to express different genes and mRNAs Alternative splicing of mRNA can lead to different polypeptides Some tissues will use a different genetic code to produce different polypeptides from the same mRNA Which of the following is the most critical to how bacterial ribosomes recognize a start codon? The 5s rRNA The 5s rRNA The 18s rRNA The 28s rRNA Teh 50s rRNA A new antibiotic is being developed that targets a component of bacterial translation initiation. Which of the following could this drug target? Kozak sequence Shine-Delgarno sequence eIF2 dephophorylation IF4 cap binding complex Sequestering release factor Which of the following antibiotics when given to a patient who does not have a bacterial infection, can actually cause harm to the patient based on its mechanism of action? Doxycycline Streptomycin Kanamycin Erythromycin Clindamycin Which of the following antibiotics interferes with elongation of a polypeptide by blocking the export tunnel? Doxycycline Streptomycin Kanamycin Erythromycin Clindamycin Which of the following antibiotics interferes with elongation of a polypeptide by inhibiting peptidyl transferase? Doxycycline Streptomycin Kanamycin Erythromycin Clindamycin A combination of which of the following would cause gene transcription? A repressor and its corepressor A repressor and its effector A repressor and its inhibitor An activator and its inhibitor An activator and its effector Which of the following lactose genes is constitutively active? lacA lacI lacO lacY lacZ Which of following combinations would produce the most lac mRNA? No glucose, no lactose Glucose present, no lactose No glucose, lactose present Glucose present, lactose present Sugar is sugar it doesn't matter During the process of conjugation, which of the following is duplicated in a noncontinuous fashion? The donor’s remaining plasmid strand The recipients new plasmid strand Both are noncontinuous replication Both are continuous replication Bacterial DNA is single stranded and does not need to be duplicated Which of the following mechanisms of genetic transfer can create partial diploids? Conjugation HFR conjugation F' Conjugation Transformation Transduction Nondisjunction events can cause a multitude of genetic conditions like trisomies and monosomies. Errors in which step of cell division can cause these events? Prophase Metaphase Anaphase Telophase Cytokines Which of the following activation mutations on a protooncogene would result in a new/novel protein? Coding mutation Regulatory mutation Translocation Gene amplification Gene deletion Which of the following cyclin dependent kinases (CDKs) is properly matched with its cyclin? CDK4, cyclin A2 CDK6, cyclin D CDK2, cyclin D CDK2, cyclin B1 CDK1, cyclin E Activation of a receptor tyrosine kinase by a growth factor is most likely to lead to which of the following? Activation of various apoptotic pathways Increased AMPK levels Decreased RAS and RAF leading to an increase in MEK Phosphorylation of BAD by AKT Decreased transcription and protein synthesis Phosphorylation of MEK will lead to activation of which of the following? RAS RAF MAPK Jun and fos Myc and fos Mutations or deletions in which of the following tumor suppressor genes is most likely to cause an increased risk in the most types of cancer? RB1 TP53 APC BRCA1/BRCA2 MLH1/MSH2 Which of the following mutations in a tumor suppressor gene is most likely to lead to increased cell division? Alteration in the retinoblastoma (RB1) protein to behave as if it is constitutively phosphorylated A mutation that would cause p53 to remain permanently bound to DNA transcribing p21 and BAX Mutation in adenomatous polyposis coli (APC) that leads to the inability to release B-catenin Alteration in the retinoblastoma (RB1) protein to bind permanently to E2F Mutations in BRCA1/BRCA2 that lead to increase activity in homologous recombination Which of the following drugs/medications would be effective in treating both breast and prostate cancer? Tamoxifen Aromatase inhibitors Trastuzumab Taxanes Pertuzumab Brenda is a 12 year old girl who was born with down syndrome caused by Robertsonsonian translocation. Which of the following is representative of her karyotype? 47, XX 47, XY 47, XXY 46, XX 46, XY John and his wife Kate have been trying to conceive for five years when they seek out your help as a genetic counselor. You discover it is a problem with John that is usually subclinical resulting in a male who is often tall with an IQ that is slightly below normal but for the most part is entirely normal. Which of the following syndromes is the most likely diagnosis? Klienfelter syndrome 47, XYY Turner syndrome Trisomy X Trisomy Y Peyton was born with the karyotype 47, XXY. Which of the following disorders are they most likely to have? Trisomy 21 Robertsonian down syndrome Klienfelters Turner syndrome Trisomy X Bryson is found to have XY androgen insensitivity. Which of the following is a likely symptom of this? Absent androgen receptors Decreased androgen levels Increased androgen levels Partial deletion in the androgen formation domain External male genitalia but with non-functioning testes Which of the following chromosomes is LEAST likely to have a viable trisomy? 1 13 18 21 X A patient with down syndrome and their family were taken to a genetic counselor to better learn about the disease. After a karyotype is run on each member of the family it is discovered that the mother has a karyotype of 45 XX. Which of the following forms of down syndrome is the patient most likely to have? Trisomy 21 Robertsonian Translocation Partial trisomy 21 Trisomy 18 Trisomy 13 Which of the following disorders/diseases still has no definitive mechanistic basis for why it occurs? Trisomy 21 Trisomy 18 Trisomy 13 DiGeorge syndrome Cri du chat syndrome A patient is found to have a deletion in the AZF region of their Y chromosome. Which of the following conditions will this patient most likely exhibit? Increased secondary sex charisteristics Decreased testicle size Azoospermia External female genitalia Oligospermia A woman presents for fertility testing after struggling to get pregnant. She is below average in height and has normal cognitive function with no apparent learning disabilities. After running a few tests you learn that she is infirtle. Which sex chromosomal abnormlaity does she likely have? XXY XYY XO XXX XX Testicular DSD Which of the following diseases could be associated with the pedigree below? Cystic fibrosis OTC deficiency Hemophilia A Neurofibromatosis Huntingtons Which of the following diseases could be associated with the pedigree below? Duchenne Muscular Dystrophy Menke’s Syndrome Hemophilia A Neurofibromatosis Infantile polycystic kidney disease Which of the following diseases could be associated with the above pedigree? Huntingtons Xeroderma Pigmentosum Hemophilia A Neurofibromatosis Angelman syndrome When looking back at a patient’s family tree she start to recognize a pattern concerning an illness that has popped up occasionally in her family. She realizes that it only appears to affect the men in her family and it doesn’t seem to appear in every generation. Which of the following types of inheritance patterns does this disease follow? Autosomal Dominant Autosomal Recessive X linked Dominant X linked Recessive Mitochondrial inheritance After finding out her older brother has huntington’s disease, a woman goes and gets tested for the number of CAG repeats in the allele. It is discovered that she has 38 CAG repeats in the allele. How should this woman feel about this information? Great! She is under the cutoff limit and will not develope Huntington’s Horrible! She is above the cutoff limit and will definitely develope Huntington’s Scared! She is in the intermediate range so there is a chance she will develope the disease but not a guaranteed certainty that she will. Reluctant! Since she is a woman she will not develope Huntington’s because it displays sex limited inheritence to males. Cautious! Since she is a woman she will inactivate half of the chromosomes with the diseases allele and thus have a milder form of the disease. A young woman and her half brother (same mother) have both been diagnosed with Marfan’s syndrome while neither of their respective parents have the disorder. How is this most likely possible? Marfan’s syndrome is autosomal recessive so it is quite common for the disease to skip a generation. Marfan’s syndrome is X linked recessive so it is quite common for the disease to skip a generation. Marfan’s syndrome has incomplete penetrance qualities so it does not manifest phenotypically in every generation. A spontaneous mutation arose in their mother’s germline cells that was passed down to each of her children, but the mother did not manifest the disease in her somatic cells. The mother drank too heavily in each of her pregnancies which has been shown to lead to increased chance of the developing child to develope Marfan’s syndrome A mother with an abnormal mitochondrial genome will pass the manifested disease onto which of her children? None of them All the males but none of the females All of the females but none of the males Approximately half of each sex All offspring regardless of gender A woman and her husband seek genetic counseling when they are ready to begin trying to get pregnant. The husband has an autosomal recessive condition that both the woman’s brother and father also have. The woman herself is unaffected. If the couple should choose to have a child, what is the probability that the child will be affected with the condition? 66% 75% 50% 33% 0% Errors in which of the following enzymes would lead to errors in methylation during replication? Dmnt1 Dmnt3a Dmnt3L Tet1 Tet2 If your parents somatic cells contain 1st generation imprints, then what generation imprints would be found in your child’s gametes? 1st 2nd 3rd 4th 5th Which of the following will lead to a change in expression of the imprinted genes? Deletion of a DMR which was imprinted Deletion of a DMR which was not imprinted Deletion of a nonimprinted gene upstream from the DMR Deletion of a nonimprinted gene downstream from the DMR My brain hurts Which of the following would lead to development of Silver-Russel Syndrome? Loss of maternal ICR2/Kcnq1 methylation Loss of paternal ICR2/Kcnq1 methylation Loss of maternal ICR1 methylation Loss of paternal ICR1 methylation Gain of maternal ICR1/H19 methylation When an element blocks an enhancer and promoter from interacting when placed between them, this best represents which of the following? lncRNA model Inactivation model Insulator model Methylation model Deletion model An additional gain of IGF2 or loss of CDKN1C would result in which of the following diseases? Beckwith-Wiedemann Silver-Russell Angelman Prader-Willi Xeroderma Pigmentosum A deletion of 15q11-13 on the paternal chromosome would most likely result in which of the following diseases? Beckwith-Wiedemann Silver-Russell Angelman Prader-Willi Osteogenesis Imperfecta Loss of the UBE3A gene on the maternal chromosome would result in which of the following diseases? Beckwith-Wiedemann Silver-Russell Angelman Prader-Willi Menke’s Which of the following structures is the smallest? Muscle tissue Myofiber Fascicle Myofibril Sarcomeres Which of the following would be considered a regulatory protein? Myosin Alpha actinin Actin Troponin Titin Which of the following would be considered a structural protein? Myosin Actin Tropomyosin Troponin Titin Which of the following structures will decrease in size during muscle contraction? A band M line I band Z disk Zone of Overlap Action potentials will have direct effects on which of the following? Ligand gated Na channels L type Ca channels Ryanodine receptors SERCA Na/Ca exchanger Calcium release from the sarcoplasmic reticulum will then go and bind to which of the following? Actin Myosin Tropomyosin Troponin C Troponin I ATP is directly responsible for which of the following in skeletal muscle contraction? Power stroke Cross bridge formation Cross bridge formation “Cocking” they myosin head Moving the tropomyosin Which of the following is responsible for restocking the sarcoplasmic reticulum with calcium? SERCA PMCA Na-Ca exchanger Ryanodine channels L type Ca channels Once you become a very rich doctor you decide to be shallow and marry a trophy husband/wife. When they are getting botox injection into their face, how is that affecting muscle contraction? Inhibits the action potential from the nerve Prevents acetylcholine release Inhibits depolarization of the sarcolemma Inhibits muscle action potential Inhibits breakdown of acetylcholine After all your years of hard work and making bank you decide to reward yourself with a trip to the beautiful wilds of South America. While hiking through the jungle you stumble upon some indiginous tribes in the area. They are not as happy to see you as you are to see them and decide to shoot you with arrows dipped in curare poison. In your last thoughts of life you remember that curare’s mechanism of action is which of the following? Blocks voltage gated sodium channels Prevents acetylcholine exocytosis Binds and opens Ach channels but is hydrolyzed very slowly thus blocking further action potentials Competitively binds ACh receptors and block end plate potential Receptor antagonist to ryanodine receptors Which of the following drugs would you give to a patient suffering from Myasthenia Gravis? Tetrodotoxin Botulism Toxin Succinylcholine Cholinesterase Inhibitors Dantrolene Dylan is an avid crossfitter. Today’s Halloween workout of the day includes holding heavy weights in front of his chest like Frankenstin and grunting like a true crossfitter. Which of the following allows him to hold these weight for a long period of time? Crossfitters are superhuman Incomplete tetanus Complete tetanus Precise muscle control Asynchronous motor unit summation Paul was able to increase his deadlift by 15 lbs when he fixed his hand form from being flexed with his hands curled under as opposed to straight out under him. Which of the following properties of length-tension relationship explains why this is? A short M-line to Z-line A short Z-line to Z-line Thin filaments that reach each other Generous zone of overlap No overlap between thick and thin filaments Which of the following explains why it is easier to lift a spoonful of ice cream to your mouth than it is to put the whole tub of ice cream to your face? The tension of the spoonful is less The tension of the spoonful is more The load of the spoonful is more The load of the ice cream tub is less The tension of the ice cream tub is less Which of the following determines the maximal velocity of muscle shortening? The type of actin and myosin involved The rate of cross-bridge turn over The initial overlap of thick and thin filaments The length of the muscle fibers The length of the muscle fibers When attempting to lift a full size car, which type of muscle contraction is most likely occurring? Isometric Concentric Isotonic Eccentric Isotonic Isotension Isoload During which of the following phases is more calcium pumped into the sarcoplasmic reticulum then being released by ryanodine channels? Latent Period Lag phase Contraction phase Relaxation phase Contraction phase Which of the following is best described as repeated contractions followed by some relaxation? Twitches Incomplete Tetanus Complete Tetanus Wave summation Recruitment Which of the following combinations of muscle architecture would result in a muscle being the fastest and strongest? Short with small cross sectional area Short with large cross sectional area Long with small cross sectional area Long with large cross sectional area Muscles are like people, they’re all equal Most of the energy that supplies sustained, long term contraction is derived from which of the following? Oxidative metabolism of fatty acids Anerobic metabolism of fatty acids Anerobic metabolism of glucose Metabolism of proteins Break down of Nucleic acids Which of the following would contribute LEAST to fatigue? Depletion of metabolites Decreased oxygen availability Abundant glycogen stores Extreme heat Increased nerve signal transmission A person is found to have no available satellite cells. What would this person be unable to do in comparison to other individuals? Increase muscle size Replicate his muscle cells Change from one muscle type to another Heal from a denervation injury Repair damaged muscle tissue Usain bolt has decided to switch events and take his talents to marathon running. During his endurance training which of the following muscle fiber types is he attempting to develope more of? Type 2b Type 2a Fast oxidative Slow oxidative Fast glycolytic Binding of Ne/E to β-adrenergic receptor activates adenylyl cyclase resulting in the formation of cAMP. In reference to calcium levels, explain how this process causes a change in blood volume through blood vessels? This turns off ATPase activity inhibiting the binding of ATP causing muscles to dilate This turns on ATPase activity causing the binding of ATP causing muscles to constrict This activates PLC to form IP3 and DAG resulting in the release of Ca causing blood vessels to dilate This activates PLC to form IP3 and DAG resulting in the release of Ca causing blood vessels to constrict The latch state phenomenon seen in smooth muscles is partially responsible for you not shitting yourself. Which of the following explains this phenomenon? cAMP binds to MLCK to prevent it from releasing ADP They are always fully contracted Actin and myosin form stronger connections than in skeletal muscle Actin and myosin in smooth muscles are always partially connected ATP is degraded faster The dense bodies found in smooth muscle are the most similar to which of the following found in skeletal muscle? Thin filaments Thick filaments Z lines M lines Titin Where are you most likely to find multiunit smooth muscle cells? Levator Palpebrae superioris Myocardium Myometrium Arrector Pili Detrusor Single unit smooth muscle is similar to cardiac muscle in which of the following ways? They arrange their actin and myosin into sarcomeres They are interconnected by gap junctions They use intermediate filaments to anchor their alpha actinin They only get calcium from their intracellular stores They both use MLCK in order to activate the myosin Which of the following are responsible for allowing extracellular calcium to enter into a smooth muscle cell? Ryanodine channels IP3 gated calcium channels SERCA PMCA L type Ca Channels Which of the following would prevent smooth muscle relaxation? Inhibition of Na/K ATPase Inhibition of MLCK Increased SERCA activity Dephosphorylation of MLC-2 Activation of a Gs G protein coupled receptor Plateaued action potentials in smooth muscle most resemble the actions potentials of which of the following? Skeletal Muscle Afferent Neurons Contractile Cardiac Tissue (Myocardium) Conducting Cardiac Tissue (Pacemaker) Efferent Neurons Which of the following correctly identifies the relationship between contractility, afterload, force and velocity? Contractility and velocity are directly related; afterload and force are inversely related Contractility and force are inversely related; afterload and velocity are directly related Contractility and force are inversely related; afterload and velocity are inversely related Contractility and force are directly related; afterload and velocity are inversely related Contractility and force are directly related; afterload and velocity are directly related Digoxin is a medication given to patients with congestive heart failure. It works to increase contractility of the heart. What effect would this have on the heart? It would increase end diastolic volume which would increase stroke volume It would decrease end diastolic volume which would increase stroke volume It would increase end systolic volume which would increase stroke volume It would decrease end systolic volume which would increase stroke volume It would decrease end systolic volume which would decrease stroke volume Lucus was put on lisinopril to help lower his blood pressure. What effect would this have on cardiac output? It would decrease end systolic volume which would increase stroke volume It would increase end systolic volume which would decrease stroke volume It would decrease end systolic volume which would decrease stroke volume It would increase end systolic volume which would increase stroke volume It would decrease afterload which would decrease stroke volume Palloidin is a toxin found in the death cap mushroom that is lethal. It works by binding actin filaments. Which of the following explains what happens as this toxin is absorbed in the liver? It leads to the stabilization of actin which prevents it from being able to contract muscles It leads to the breakdown of actin which prevents the pulling apart of sister chromatids It leads to the breakdown of actin which prevents cells from moving It leads to the conformation of F-actin into G-actin thus changing its ability to contract muscles It leads to the conformational of G-actin into F actin which changes its ability to contract muscles. Which two amino acids are cross linked by transglutaminase in the skin? Glutamine and histidine Glycine and histidine Glutamine and lysine Glycine and lysine Glycine and histidine Time is Up!