BIOCHEM C785 Final Exam Latest update With Complete Solution 2023

Which mRNA sequence results in a polypeptide that contains three amino acids? - Correct answer-5' - CUU GAU ACU UAG - 3' Which RNA sequence would end in the following polypeptide? Phe-Thr-Val-Stop - Correct answer-5' - UUC ACA GUA UAA - 3' What is the complementary sequence for the following DNA sequence? 5' - GCC ATC TCG AAT - 3' - Correct answer-5' - ATT CGA GAT GGC - 3' Assuming 100% reaction efficiency, how many DNA copies are created after the completion of four complete PCR cycles? - Correct answer-16 What is the function of DNA polymerase in the process of PCR? - Correct answer-It recognizes the primers and uses the available dNTPs to replicate the template DNA sequence. 5' - [...] ATT CGC TAG GGC [...] - 3' − Normal DNA 5' - [...] ATT CGC GAG GGC [...] - 3' − Mutant DNA Which type of mutation and outcome characterizes the Mutant DNA? - Correct answerA missense mutation leading to a longer protein In sickle-cell disease, the glutamic acid (Glu) at position number seven is mutated to valine (Val). What change in codons corresponds to this mutation? - Correct answer-GAA to GTA What are possible blood types of the parents of a patient with blood type AB? - Correct answer-A and B Which pair of chromosomes accurately depicts the genotype of a person with an autosomal recessive mutant HBB allele and sickle cell anemia? - Correct answer-option 3- 2 mutant genes on chromosome 11 Which pair of chromosomes accurately depicts the genotype of a person with an Xlinked recessive mutant ALAS2 allele and sideroblastic anemia? - Correct answeroption 3, mutated allele Studies have shown that increased expression of two genes called SIRT1 and SIRT2 is associated with chronic exposure to cocaine and contributes to drug addiction. What difference in the regions of the SIRT1 and SIRT2 genes in people addicted to cocaine increases their expression? - Correct answer-The nucleosomes become more widely spaced. Mice with low levels of agouti gene expression tend to have yellow fur and are obese, while mice with higher levels of expression are brown and of normal weight. Studies show that expression of the agouti gene in mice can be controlled by epigenetics. Mice with low levels of agouti gene expression tend to have yellow fur and are obese, while mice with higher levels of expression are brown and of normal weight. Studies show that expression of the agouti gene in mice can be controlled by epigenetics. What scenario describes epigenetic regulation of the agouti gene? - Correct answerMother mice fed methyl-rich diets during pregnancy give birth to offspring with decreased agouti gene expression compared to those fed a methyl-poor diet. Oxidative damage to DNA can often result in the alteration of a single nucleotide. Which DNA repair mechanism would repair this type of damage? - Correct answer-Base excision repair Xeroderma pigmentosum (XP) is a recessive genetic disease that occurs when one or more of the genes that perform nucleotide excision repair are nonfunctional. Why do XP patients have a much higher incidence of skin cancer than the general population? - Correct answer-The mutation rate of all other genes is higher due to failure to repair. Which reaction is responsible for the formation of polypeptides? - Correct answerDehydration Which portion of the amino acid is inside the box? - Correct answer-Carboxyl group Which amino acid side group is polar? - Correct answer-option 2-one with charge When placed within a polypeptide chain, which amino acid would interact most favorably with nonpolar amino acids? - Correct answer-option 2-non polar Which term describes the order of amino acids in a peptide chain? - Correct answerPrimary structure When using heat to denature a protein, which force is the first to be disrupted as temperature increases? - Correct answer-Hydrophobic interactions A commonly used technique for protein denaturation is adding an acid or a base to dramatically change the pH. Which force is most impacted by this change in pH? - Correct answer-Ionic bonds An active elderly patient is becoming frequently disoriented, having trouble recalling her daily routine, and becoming aggravated easily. She forgets words and places and has difficulty recognizing her children. Which biochemical event is responsible for this patient's behavior? - Correct answerProtein aggregation In which situation would altering a protein structure lead to a disease state? - Correct answer-A mutation in aconitase blocks an essential step in aerobic metabolism How can an alteration in protein structure lead to a disease state? - Correct answer-A mutation replaces an isoleucine with an aspartic acid in a transcription factor protein, which blocks the normal folding of the protein and its function in the expression of certain genes. Which structural level shows the greatest difference when replacing denatured proteins with a denatured single subunit protein? - Correct answer-Tertiary Frying an egg changes the egg white from a clear liquid to an opaque solid. Which molecular change in the albumin protein causes this change in appearance? - Correct answer-Hydrophobic interactions form between denatured egg white proteins. What is the driving mechanism of plaque formation in prion diseases? - Correct answerPropagation of misfolding from one protein to another Which feature of a protein made of a single polypeptide chain is most directly responsible for its function? - Correct answer-Three-dimensional structure How does the Bohr effect describe the relationship between carbon dioxide levels, blood pH and the amount of oxygen bound to hemoglobin? - Correct answer-An increase in carbon dioxide production leads to a decrease in blood pH, causing hemoglobin to release oxygen more readily. Which statement describes the binding of oxygen gas to a heme group? - Correct answer-The binding of oxygen gas to heme changes the structure of the heme group. Which characteristic of myoglobin makes it an effective oxygen storage molecule? - Correct answer-It has a high affinity for oxygen. At low O 2 concentrations, how does myoglobin's affinity for O 2 relate to hemoglobin's affinity for O 2? - Correct answer-Myoglobin has a much greater affinity for O 2 than hemoglobin does. Which pair of binding curves accurately compares how hemoglobin and myoglobin become saturated with oxygen as a function of the partial pressure of oxygen? - Correct answer-option 2 How does pH level promote the deoxygenated conformation of hemoglobin? - Correct answer-When pH lowers, O 2 binds with excess HCO 3 - in the blood, which blocks its ability to bind to the heme group and pull it into the dome conformation. What is occurring in surrounding tissues as the amount of hemoglobin saturated with oxygen increases? - Correct answer-The amount of carbon dioxide decreases. What is feedback inhibition? - Correct answer-Reversible, noncompetitive inhibition of an enzyme in a pathway by a product of that pathway Which form of enzyme regulation is likely to be used by an organism to control the catalytic activity of its enzymes as it adapts to changes in available nutrients? - Correct answer-Feedback inhibition How does heating beyond optimum temperature inactivate enzymes? - Correct answerBy changing the enzyme's three-dimensional shape What occurs in enzymes during the phenomenon of induced fit? - Correct answerSubstrate binding causes a conformational change. Which portion of the enzyme does the substrate bind to? - Correct answer-Active site Based on the provided enzyme pathway below, what would occur as a result of a defect in the enzyme which catalyzes the D→E reaction? - Correct answer-The amount of C would increase. Which type of inhibition occurs when a particular drug binds to the allosteric site of an enzyme and subsequently changes the enzyme's structure - Correct answer-Non competitive A particular enzyme acts on the succinate substrate and is inhibited by malonate. Which type of inhibition is expected based on the following structures? - Correct answer-Competitive What occurs immediately after the appropriate molecule enters the active site of an enzyme? - Correct answer-The enzyme binds the molecule to form an enzymemolecule complex. Which type of inhibition is depicted in the following reaction scheme? - Correct answerFeedback inhibition Which type of inhibition is depicted in the following figure? - Correct answer-non competitive How is energy provided for ATP production during the final stage of aerobic metabolism? - Correct answer-Protons diffuse through a transmembrane protein. How does insulin impact carbohydrate metabolism? - Correct answer-It stimulates the uptake of glucose from the blood by cells in the body. How does insulin reduce blood glucose levels? - Correct answer-It increases the translocation of GluT4 transporters to the cell membrane. Approximately how many ATP molecules can be produced from a single molecule of glucose during aerobic metabolism? - Correct answer-30 Which cellular condition prompts the cell to perform fermentation rather than the citric acid cycle? - Correct answer-Lack of O 2 What causes the symptoms of noninsulin-dependent (Type 2) diabetes? - Correct answer-There are not enough GluT4 transporters on plasma membranes. How many molecules of acetyl-CoA will the following fatty acid produce? - Correct answer-8 Which metabolic pathway involves coenzyme A, NAD, and FAD? - Correct answer-Beta oxidation Which molecule is pyruvate directly converted to under aerobic conditions? - Correct answer-Acetyl-CoA How many molecules of lactate are required to produce one molecule of glucose? - Correct answer-2 What is the role of oxygen in aerobic metabolism? - Correct answer-It acts as the final electron acceptor in the electron transport chain Which pathway is triggered by increased levels of epinephrine and provides a quick increase in available glucose? - Correct answer-Glycogenolysis Which type of molecule can be used in gluconeogenesis? - Correct answer-Amino acids