Biochemistry Module 6 Practice Exam

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• Which statement best matches shuttle systems with their electron donors in mitochondria?
• Which statement correctly compares the malate–aspartate shuttle and the glycerol-3-phosphate shuttle in terms of energy yield per cytosolic NADH?
• Purines are characterized by having what kind of ring structure?
• Which pathway provides most NADPH in a typical cell?
• Which vitamin-derived cofactor is essential for the pyruvate dehydrogenase and α-ketoglutarate dehydrogenase complexes?
• What is the primary metabolic function of acetyl-CoA carboxylase (ACC)?
• Uracil in RNA is the functional analog of which DNA base?
• Describe substrate channeling and one potential metabolic advantage.
• Which statement correctly describes how the degree of unsaturation in fatty acids influences melting point?
• Which statement accurately describes how essential amino acids are determined for humans?
• How many rings do pyrimidine bases have in their ring structure?
• Which description correctly states the main outputs of the pentose phosphate pathway and how they are produced?
• What is the function of the pentose phosphate pathway’s oxidative phase?
• Which category of bases has two rings in its structure?
• Which statement best describes competitive inhibition?
• Which base is not a pyrimidine base?
• Which base pairs with cytosine in Watson-Crick base pairing?
• The double helix of DNA is stabilized mainly by which type of bonds?
• The conclusion that G and C are present in DNA in equimolar amounts is credited to which scientist?
• Which enzyme catalyzes the conversion of pyruvate to oxaloacetate in gluconeogenesis?
• Compare the malate-aspartate shuttle and the glycerol-3-phosphate shuttle in terms of tissue distribution and energy yield.
• Which TCA cycle enzyme is inhibited by high NADH levels and energy status?
• Which enzyme links glycolysis to the TCA cycle by converting pyruvate to acetyl-CoA, and how is its activity regulated by NADH and acetyl-CoA?
• How does acetyl-CoA regulate the pyruvate dehydrogenase complex (PDH) and why is this regulation important?
• What is the role of acetyl-CoA carboxylase in metabolism and what cofactor is required?
• Which group marks the 3' end of DNA?
• Which statement best describes the regulatory mechanism of the pyruvate dehydrogenase complex via reversible phosphorylation?
• Which statement best describes the role of vitamins as coenzymes in metabolism, with an example involving thiamine pyrophosphate (TPP) in pyruvate dehydrogenase?
• Which statement about beta-sheets is true?
• Which amino acids are glucogenic and which are ketogenic? Provide two examples of each.
• How is the order of nucleotides in DNA written?
• Acetyl-CoA serves as a metabolic hub; which statement is true?
• Which of the following acts as a coenzyme?
• Which enzyme catalyzes the final step of gluconeogenesis, converting glucose-6-phosphate to glucose?
• What mechanism transports acetyl-CoA from mitochondria to cytosol for lipid synthesis?
• Which base pairing forms two hydrogen bonds?
• What is the difference between standard free energy change and actual free energy change in cells, and why is ΔG more informative?
• Which statement describes the fate of acetyl-CoA produced in mitochondria for fatty acid synthesis?
• Where is citrate exported from mitochondria for fatty acid synthesis and what enzyme cleaves it?
• In glycolysis under aerobic conditions, what is the net ATP and NADH gained per glucose?
• How do dehydrogenases and oxidoreductases differ in cofactor usage (NAD+/NADP+) and cellular roles?
• In nucleic acid chemistry, compounds that contain an organic nitrogen-containing base, sugar, and phosphate group are called ___.
• Compare allosteric regulation by fructose-2,6-bisphosphate on PFK-1 with hormonal control of glycolysis by insulin and glucagon.
• Identify three allosteric regulators of PFK-1 and indicate whether they activate or inhibit the enzyme.
• Which statement correctly defines oxygen debt and describes the lactate shuttle?
• Which glycolytic enzyme is highly regulated by ATP, AMP, and fructose-2,6-bisphosphate?
• What type of bonds hold the two DNA strands together in base pairing?
• In DNA, the base pair held together by three hydrogen bonds is ___.
• What does a Hill coefficient greater than 1 signify in enzyme kinetics?
• Which enzyme catalyzes the first committed step of the urea cycle and what molecule activates it?
• What is the role of NADPH in redox balance and which pathway provides most cellular NADPH?
• In the citric acid cycle, per acetyl-CoA entering the cycle, which set of products is produced?
• Differentiate allosteric enzymes from Michaelis-Menten enzymes.
• Which molecule provides NADPH for reductive biosynthesis and how is it generated in the cytosol?
• From palmitate (C16) in beta-oxidation, how many acetyl-CoA molecules are produced and how many beta-oxidation cycles occur?
• Purines have how many rings, and how many nitrogens per ring?
• Why do red blood cells rely on glycolysis for ATP production and what happens to pyruvate under anaerobic conditions?
• What does the Ramachandran plot show?
• What is the complementary strand of RNA for the base sequence RNA 5'-GCATGAGCC-3'?
• Uracil is a pyrimidine base primarily found in RNA.
• Per beta-oxidation cycle, what electron carriers are produced?
• Which type of RNA is referred to by the abbreviation mRNA?
• In enzyme-catalyzed reactions, what role does FAD play?
• How is energy charge defined and how does it regulate glycolysis?
• Which enzyme catalyzes the conversion of oxaloacetate to phosphoenolpyruvate in gluconeogenesis?
• In RNA, which base is used in place of thymine?
• Which form of DNA is left-handed?
• Which statement correctly describes alpha-helix geometry?
• Which enzyme catalyzes the conversion of pyruvate to acetyl-CoA?
• For basic amino acids, how is the isoelectric point calculated?
• Which statement correctly identifies primary active transport?
• Besides ATP, which other nucleotide is part of energy storage in cells?
• What is the set of three sequential nucleotides that encodes for a particular amino acid?
• Which base is a pyrimidine that is not found in RNA?
• Which cofactor does succinate dehydrogenase use?
• Which statement about DNA forms being right-handed is true?
• Which statement best describes the primary control point for carbohydrate metabolism in the liver and its hormonal regulation?
• In energy stress, which enzyme is activated by a high AMP/ATP ratio to promote catabolic pathways?
• What is the function of FAD?
• Gluconeogenesis from glycerol enters as which intermediate?
• Which pyrimidine base is present in both DNA and RNA?
• Which statement correctly explains the roles of NAD+ and NADP+/NADPH in metabolism?
• Which statement correctly describes the respiratory quotient (RQ) and its typical values for carbohydrate and fat oxidation?
• Which enzyme initiates the oxidative branch of the pentose phosphate pathway?
• Which glycolytic enzyme catalyzes the step that reduces NAD+ to NADH?
• Which statement best describes the function of glucose-6-phosphate dehydrogenase (G6PD) in the pentose phosphate pathway and the effect of its deficiency?
• Which compound is produced in abundance by the pentose phosphate pathway and used for nucleotide synthesis?
• Which base pairing forms three hydrogen bonds?
• How many hydrogen bonds are formed between adenine and thymine/uracil?
• In the Watson-Crick model for the DNA double helix, which statement is NOT true?
• Which description correctly explains how signal peptides direct proteins to mitochondria, chloroplasts, and secretory pathways?
• How many hydrogen bonds are formed between guanine and cytosine?
• How does ATP yield from glucose oxidation differ between prokaryotes and eukaryotes, considering cytosolic NADH shuttles?
• Which base pairs with cytosine in RNA?
• DNA is built from which of the following?
• Which term describes a nucleoside that contains a purine base?
• Which group marks the 5' end of DNA?
• Which nucleic acid is responsible for using the encoded genetic information to produce proteins found in living organisms?
• Which statement best describes uncompetitive inhibition?
• Which component differentiates a nucleotide from a nucleoside?
• Which base is characteristically used in DNA and is not typically found in RNA?
• Which type of RNA functions to carry genetic information from DNA to the ribosome?
• Which tissue primarily uses the glycerol-3-phosphate shuttle for transferring reducing equivalents into mitochondria?
• Which are the three irreversible steps of glycolysis and their enzymes?
• Which term describes a nitrogenous base with a single ring?
• Which signaling cascade mediates insulin-stimulated GLUT4 translocation to the plasma membrane?
• In RNA, adenine always pairs with which base?
• Where does the amino acid attach to the tRNA?
• In DNA, which base pairs with adenine?
• In beta-oxidation of palmitoyl-CoA, how many cycles occur and what are the products?
• In DNA, adenine pairs with thymine.
• Which vitamin acts as a cofactor for carboxylation reactions in metabolism?
• The pentose sugar in RNA is ribose.
• Which base is found in DNA but not RNA?
• Which statement about the role of NAD+/NADH and FAD/FADH2 is true regarding metabolic flux when the NAD+/NADH ratio is high?
• What is activation energy and how do enzymes affect it?
• Which statement best defines substrate channeling and provides an example pathway?
• What percentage of ribosomes' mass is composed of rRNA?
• What is the rate-limiting enzyme in cholesterol synthesis?
• How is HMG-CoA reductase activity regulated?
• Which enzyme cleaves citrate in the cytosol to produce acetyl-CoA for fatty acid synthesis?
• In RNA, which base pairs with adenine?
• Which base is a purine?
• A nucleotide is composed of which components?
• Which shuttle more efficiently transfers reducing equivalents into mitochondria?
• What experimental data would indicate that an enzyme exhibits allostery rather than simple Michaelis-Menten kinetics?
• Which processes involve substrate-level phosphorylation?
• Which tissue primarily uses the malate-aspartate shuttle to transfer reducing equivalents into mitochondria?
• DNA sequence orientation is written in which direction?
• What is the role of chaperones in protein folding, with examples such as Hsp70 and chaperonins?
• Which statement about pyruvate dehydrogenase complex inhibition is true?
• What does heterocyclic mean?
• In competitive inhibition, how do the apparent Km and Vmax change?
• In hepatic metabolism, how do insulin and glucagon regulate PFK-1 activity via PFK-2 and fructose-2,6-bisphosphate?
• Which structural feature is true of thymine?
• What is the approximate ATP yield per NADH and per FADH2 in oxidative phosphorylation, and how many protons are pumped per NADH?
• What is the role of malonyl-CoA in fatty acid metabolism?
• Which enzymes bypass irreversible glycolytic steps in gluconeogenesis?
• Which statement best describes noncompetitive inhibition?
• Which set of techniques is commonly used to measure enzyme activity?
• How does the bicarbonate buffer system maintain systemic pH?
• A major component of RNA, but not DNA is UMP. Which nucleotide monophosphate is a major component of RNA but not DNA?
• How do dietary carbon sources influence the Cori cycle during intense exercise?
• What is the most noticeable difference between A-form and Z-form DNA?
• What percentage of ribosome mass is protein?
• Uracil is primarily found in which nucleic acid?
• Which molecule serves as the two-carbon donor in the first committed step of fatty acid synthesis?
• Name which ETC complexes pump protons and which do not.
• Explain resonance stabilization and how it affects peptide bond planarity and protein secondary structure.
• Which term describes a nitrogenous base with a double-ring structure?
• Which statement correctly contrasts energy yield and substrate use in fed versus fasting states?
• Describe the structure of amino acids and the concept of zwitterions at physiological pH.
• Which shuttle transfers electrons to FAD in mitochondrial glycerol-3-phosphate dehydrogenase?
• What is the complementary strand of DNA for the base sequence 5'-GCATGAGCC-3'?
• What is the overall energy balance concept in metabolism and how do catabolic and anabolic pathways satisfy it?
• What is the approximate standard free energy change for ATP hydrolysis used to drive unfavorable reactions?
• How does the liver regulate PFK-1 via fructose-2,6-bisphosphate and how do insulin and glucagon effect it?
• In glycolysis, what effect would high cellular ATP have on PFK-1 activity?
• Which base contains a methyl group as part of its structure?
• Which component drives ATP synthase to phosphorylate ADP to ATP?
• Which of the following is a second messenger in cells?
• What statement best differentiates channels and carriers in membrane transport?
• Non-covalent interactions contribute to the 3D shapes and structures of RNA molecules. Which statement best describes this contribution?
• Which enzyme catalyzes the phosphorylation of glycerol to glycerol-3-phosphate in liver metabolism?
• Which type(s) of DNA have a right-handed helix?
• Explain what a biochemical standard state is and how standard free energy changes are used in metabolic calculations.
• Which molecule is a classic example of a high-energy phosphate donor used to power many biochemical reactions?
• Pyrimidines have how many rings and how many nitrogens?
• Why is Complex II of the ETC not proton-pumping while still participating in the chain?
• A codon is defined as which of the following?
• Which scientist is credited with the observation that guanine and cytosine occur in DNA in equal amounts?
• Which product of the oxidative phase of the pentose phosphate pathway is used for nucleotide synthesis?
• Which base pairs with cytosine in Watson-Crick base pairing?
• What is the citrate shuttle and why is it important for lipogenesis?
• In the TCA cycle, which molecule is produced directly and can be converted to ATP?
• Which statement correctly describes the fate of electrons from FADH2 in the Electron Transport Chain?
• Which lipoprotein participates in reverse cholesterol transport to the liver?
• What is the Warburg effect?
• How does the proton motive force drive ATP production in ATP synthase?
• Which amino acids contribute to gluconeogenesis via conversion to oxaloacetate or pyruvate?
• Which condition would increase pyruvate dehydrogenase (PDH) activity?
• Which types of secondary structure are favored due to peptide bond planarity?
• A pyrimidine found in all RNA, but not in DNA is ___.
• Which statement about the DNA double helix is false?
• Purines are characterized by containing two fused rings.
• The pentose sugar in DNA is known as 2-deoxyribose.
• In DNA, the pentose sugar serves as the monosaccharide. What is it?
• Which metabolite signals high energy status and shunts carbon to fatty acid synthesis by inhibiting PDH?
• Which lipoprotein transports dietary triglycerides from the intestine?
• Which base pairs with Guanine in Watson-Crick base pairing?
• Which energy carrier is primarily regenerated by lactate dehydrogenase during anaerobic glycolysis?
• In gluconeogenesis, which enzyme catalyzes the conversion of oxaloacetate to phosphoenolpyruvate?
• Which statement best describes the non-oxidative phase of the PPP?
• Name a key regulator of the TCA cycle and describe how its activity is modulated by energy state.
• Which statement best describes the hydrogen bonding patterns of alpha-helices and beta-sheets?
• Name three non-carbohydrate carbon sources for hepatic gluconeogenesis.
• In RNA, cytosine always pairs with which base?
• Thymine belongs to which class of nitrogenous bases?
• Which statement correctly describes the geometry of a typical alpha-helix in terms of handedness and residues per turn?
• Which metabolic pathways primarily rely on NADPH for reducing power?
• Which hormone regulates F2,6BP by decreasing its levels through phosphorylation of PFK-2?
• The monomers of RNA nucleic acids consist of three parts. What are those three parts?
• Which statement best describes ATP yield from glucose oxidation through glycolysis, PDH, and TCA, considering shuttle variability?
• Which statement accurately describes the role of iron-sulfur clusters in metabolism and their sensitivity to oxidative stress?
• State the Michaelis-Menten equation and describe what Vmax and Km represent.
• Under which metabolic condition are ketone bodies produced, and which tissue primarily uses them?
• What is ATP synthase and what are its F0 and F1 components?
• Two purines found in DNA are ___.
• In DNA, adenine always pairs with which base?
• Two DNA strands are described as complementary. What does this mean?
• Which base has a methyl group and is thus characteristic of DNA?
• What is the rate-limiting step of glycolysis and which enzyme catalyzes it?
• Which lipoprotein delivers cholesterol to peripheral tissues?
• Which statement correctly lists activators and inhibitors of phosphofructokinase-1 (PFK-1)?
• The isoelectric point (pI) is the pH at which an amino acid has no net charge. For acidic residues, how is the pI determined?
• What pentose sugar is a constituent of RNA?
• Which molecules inhibit the pyruvate dehydrogenase complex?
• Which molecule strongly activates PFK-1?
• What pentose sugar is a constituent of DNA?
• Which base is a purine?
• Provide a brief overview of nucleic acid metabolism: de novo synthesis vs salvage pathways for purines and pyrimidines.
• Which of the following bases is a purine?
• Which set of base pairs represents complementary base pairs in nucleic acids?
• Which cytosolic process regenerates NAD+ during anaerobic glycolysis and why is it necessary?
• Which complex of the electron transport chain is also part of the TCA cycle and uses FAD as a cofactor?
• Which equation correctly describes the Michaelis-Menten relationship, and what Km and Vmax represent?
• How does malonyl-CoA regulate fatty acid oxidation and synthesis to prevent futile cycling?
• Which statement best describes how alpha-helix and beta-sheet stability are determined?
• Which enzyme catalyzes the carboxylation of acetyl-CoA to malonyl-CoA, and what cofactor is essential for the reaction?
• What is the primary purpose of the pentose phosphate pathway and which cofactor is produced in abundance?
• What is the role of mitochondria in apoptosis, especially regarding cytochrome c and caspase activation?
• Which statement correctly pairs a chaperone type with its function?
• Which bases are purines?
• What does Km represent in Michaelis-Menten kinetics?
• Which statement about pyrimidine bases is true?
• What are aminotransferases and which cofactor do they require?
• In DNA, base pairing is between complementary bases. Which pairing is correct?
• If 65% of the ribosome is rRNA, what percentage is protein?