Biochem Quiz No. 2 PDF

Quiz No.2 in FE 417: Elective I - Biochemistry I. Nucleic Acids 1. Which of the following best describes nucleic acids as molecules that store and express genetic information and are made up of nucleotide monomers that contain a sugar, a phosphate group, and a nitrogenous base? A. Proteins B. Lipid...

Quiz No.2 in FE 417: Elective I - Biochemistry I. Nucleic Acids 1. Which of the following best describes nucleic acids as molecules that store and express genetic information and are made up of nucleotide monomers that contain a sugar, a phosphate group, and a nitrogenous base? A. Proteins B. Lipids C. Nucleic Acids D. Polysaccharides 2. Which event in the history of nucleic acids includes Friedrich Miescher’s discovery of nuclein in 1869, followed by Watson and Crick’s identification of DNA’s double-helix structure in 1953? A. Discovery of RNA synthesis B. Understanding of DNA replication C. Establishment of the genetic code D. Discovery of nucleic acids 3. Which statement explains that the double-helix structure of DNA is formed by two strands with a sugar-phosphate backbone and nitrogenous bases that pair specifically to stabilize the molecule? A. DNA is single-stranded and lacks a sugar-phosphate backbone. B. DNA is double-stranded and has a sugar-phosphate backbone with specific base pairing. C. DNA contains only purines, which form the base pairs. D. DNA does not have a consistent structure. 4. Which difference between DNA and RNA explains that RNA is single-stranded, contains ribose instead of deoxyribose, and has uracil instead of thymine in its structure? A. RNA uses uracil, is single-stranded, and contains ribose instead of deoxyribose. B. RNA is double-stranded and lacks base pairing entirely. C. RNA is chemically identical to DNA in all respects. D. RNA does not play any role in genetic information. 5. Which type of RNA, known as messenger RNA or mRNA, is transcribed from DNA and carries the instructions needed for protein synthesis in the ribosome? A. Ribosomal RNA (rRNA) B. Transfer RNA (tRNA) C. Messenger RNA (mRNA) D. Small nuclear RNA (snRNA) 6. Which pairing of nitrogenous bases in DNA occurs where adenine pairs with thymine using two hydrogen bonds, and guanine pairs with cytosine using three hydrogen bonds, ensuring the stability of the double helix? A. Adenine pairs with guanine, and cytosine pairs with thymine. B. Adenine pairs with thymine, and guanine pairs with cytosine. C. Adenine pairs with cytosine, and guanine pairs with uracil. D. Adenine pairs with thymine, and guanine pairs with uracil. 7. Which process, called hydrolysis of nucleic acids, involves breaking down DNA or RNA into nucleotides using strong acids or bases to cleave the bonds between the sugar-phosphate backbone? A. Nucleic acid hydrolysis breaks DNA or RNA into nucleotides. B. Protein synthesis builds new proteins from amino acids. C. DNA replication synthesizes a new strand of DNA. D. Lipid metabolism breaks down fats into fatty acids. 8. Which metabolic process, known as purine synthesis, ensures balanced levels of adenine and guanine by regulating their production to prevent imbalances that could lead to genetic mutations? A. Pyrimidine degradation regulates purines. B. Purine synthesis balances adenine and guanine production. C. Protein catabolism reduces genetic mutations. D. Lipid metabolism eliminates excess purines. 9. Which medical condition, commonly caused by excessive uric acid due to issues in purine metabolism, results in painful inflammation of the joints and is known as gout? A. Gout results from excessive uric acid due to purine metabolism problems. B. Diabetes mellitus causes inflammation of the joints. C. Hypertension is a condition caused by uric acid buildup. D. Anemia results in joint pain from purine accumulation. 10. Which diagnostic method, commonly used in molecular biology labs, amplifies DNA through techniques like polymerase chain reaction (PCR) to identify genetic sequences or pathogens in biological samples? A. Western blotting is used to amplify DNA. B. Polymerase chain reaction (PCR) identifies genetic sequences. C. Spectrophotometry measures DNA sequences. D. Flow cytometry detects pathogens in tissues. II. Flow of Genetic Information 11. What is the central dogma of molecular biology, which explains how genetic information flows from DNA to RNA and finally to proteins, describing the process of transcription and translation? A. DNA → RNA → Protein B. Protein → RNA → DNA C. RNA → Protein → DNA D. DNA → Protein → RNA 12. Which of the following best defines a gene as a specific segment of DNA within an organism’s genome, containing regions such as the regulatory sequences and transcribed units responsible for producing RNA or proteins? A. A chain of amino acids B. A segment of RNA responsible for transcription C. A specific segment of DNA that produces RNA or proteins D. A unit of chromosome without coding functions 13. What is the term that describes observable traits like height, coat color, or biochemical characteristics, which result from the expression of an organism's genotype influenced by both genetic and environmental factors? A. Phenotype B. Genotype C. Mutation D. Genome 14. Which repair mechanism corrects errors that escape proofreading during DNA replication, scanning for mispaired bases, excising the mismatch, and replacing it with correct nucleotides? A. Mismatch Repair (MMR) B. Base Excision Repair (BER) C. Nucleotide Excision Repair (NER) D. Homologous Recombination 15. Which phase of transcription involves RNA polymerase binding to a DNA sequence called the promoter, separating the strands, and providing a template for RNA synthesis? A. Termination B. Initiation C. Elongation D. Splicing 16. What is the primary role of messenger RNA (mRNA) in the process of protein synthesis, as it carries genetic information from DNA in the nucleus to ribosomes in the cytoplasm? A. Carrying amino acids to ribosomes B. Forming structural components of ribosomes C. Carrying genetic information for protein synthesis D. Editing and splicing DNA sequences 17. Which type of DNA damage, commonly caused by UV radiation, results in the incorrect linkage of adjacent pyrimidine bases and can disrupt DNA replication if not repaired? A. Point mutations B. Pyrimidine dimers C. Bulky adducts D. Deamination 18. What is the function of the 5' cap and 3' poly-A tail added during RNA processing, which protect the RNA from degradation and help ensure efficient translation? A. Stabilize RNA and assist ribosome binding B. Remove introns from RNA sequences C. Initiate DNA replication in the nucleus D. Enhance the rate of DNA transcription 19. Which term describes the complete genetic material of an organism, including all of its genes and non-coding sequences, that governs its growth, reproduction, and traits? A. Genome B. Chromosome C. Phenotype D. Protein 20. What is the biological process by which a DNA molecule is copied during cell division to ensure that each daughter cell receives an identical set of genetic instructions? A. DNA transcription B. DNA replication C. RNA translation D. DNA mutation III. Intermediary Metabolism 21. Which term best describes the biochemical process where intermediary metabolism occurs, involving enzyme-catalyzed reactions within cells to convert nutrients into energy and essential macromolecules for sustaining life? A. Metabolism B. Respiration C. Photosynthesis D. Fermentation 22. What is the main distinction between autotrophs and heterotrophs, considering their respective abilities to either utilize carbon dioxide as a carbon source or obtain carbon from organic molecules like carbohydrates and proteins? A. Autotrophs use sunlight, while heterotrophs use oxygen. B. Autotrophs use CO₂, while heterotrophs rely on organic molecules. C. Autotrophs consume organic molecules, while heterotrophs fix nitrogen. D. Autotrophs produce enzymes, while heterotrophs digest lipids. 23. Which phase of metabolism refers to the breakdown of complex molecules like carbohydrates and lipids into smaller, simpler molecules, releasing energy stored in the chemical bonds for cellular activities? A. Anabolism B. Photosynthesis C. Catabolism D. Glycolysis 24. What is the key difference between catabolic and anabolic processes? A. Catabolism breaks down molecules to release energy, while anabolism builds molecules using energy. B. Catabolism builds molecules, while anabolism breaks them down. C. Catabolism happens in the nucleus, while anabolism occurs in the mitochondria. D. Catabolism uses sunlight, while anabolism uses nutrients. 25. In a clinical setting, a patient is diagnosed with medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, resulting in hypoglycemia during fasting periods due to impaired fatty acid oxidation; what would be the primary therapeutic recommendation for managing this condition? A. High-protein diet with prolonged fasting periods B. Avoidance of fasting and early intervention during illness C. Supplementation of ketogenic diets with high-fat content D. Complete avoidance of carbohydrates in meals 26. Which of the following best describes the metabolic function of anabolic processes, where smaller building blocks are converted into larger macromolecules essential for growth and maintenance in living organisms? A. Degrading proteins into amino acids for energy. B. Combining simple molecules to synthesize complex ones. C. Generating small energy molecules like ATP directly. D. Recycling damaged macromolecules for cellular repair. 27. During digestion, salivary amylase is released from the salivary glands to initiate the breakdown of carbohydrates into simpler sugars; in which location does this enzyme primarily begin its action? A. Stomach B. Small intestine C. Oral cavity D. Large intestine 28. In the context of intermediary metabolism, how does the citric acid cycle (Krebs cycle) contribute to cellular energy production, considering its role in oxidizing acetyl-CoA derived from carbohydrates, fats, and proteins? A. It directly produces ATP molecules for the cell. B. It generates high-energy electron carriers like NADH and FADH₂. C. It synthesizes glucose through gluconeogenesis. D. It stores energy in the form of glycogen. 29. Which component of gastric digestion, released by the stomach lining, helps break down proteins into peptides while also defending against pathogens and preparing food for absorption in the intestines? A. Pancreatic lipase B. Gastric juice C. Bile salts D. Salivary amylase 30. A patient with inherited galactose metabolism disorder experiences vomiting and liver damage after consuming dairy products. What is the most likely diagnosis for this metabolic condition? A. Glycogen storage disease type I B. Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency C. Galactosemia D. Phenylketonuria IV. Metabolic Pathways I 31. Glycolysis is the first stage of glucose metabolism and occurs in the cytosol of cells. What is the final product of glycolysis that serves as a precursor for other metabolic pathways? A. Acetyl-CoA B. Pyruvate C. Lactate D. Citrate 32. Metabolic pathways are regulated processes consisting of enzyme-driven reactions that transform substrates into products. Which of the following is NOT a universal characteristic of metabolic pathways? A. Irreversibility of pathways B. Occurrence in specific cellular locations C. Having a committed first step D. Simultaneous occurrence throughout the entire cell 33. Unlike other energy-producing pathways, glycolysis can function both aerobically and anaerobically. What property allows glycolysis to proceed without oxygen? A. Its production of oxygen as a by-product B. Its cytosolic location and oxygen-independent reactions C. Its reliance on the electron transport chain D. Its generation of lactate in all conditions 34. The Citric Acid Cycle is vital for cellular energy production and biosynthesis. What characteristic makes this cycle "amphibolic"? A. It uses oxidative and reductive reactions. B. It functions in both anabolic and catabolic pathways. C. It occurs in multiple cellular compartments. D. It requires oxygen for every step. 35. In aerobic metabolism, glycolysis generates pyruvate, which is converted into a key compound for the Citric Acid Cycle. What is this compound? A. Lactate B. Acetyl-CoA C. Oxaloacetate D. Citrate 36. The electron transport chain transfers electrons through protein complexes and pumps protons across the mitochondrial membrane. What is the role of oxygen in this process? A. Final electron acceptor forming water B. Initiator of electron transfer C. Direct generator of ATP D. Oxidizer of NADH and FADH₂ 37. The Citric Acid Cycle generates intermediates critical for other processes in addition to energy carriers like NADH and FADH₂. How does it specifically support the electron transport chain? A. By generating a proton gradient B. By providing electron carriers for the chain C. By producing ATP directly D. By oxidizing pyruvate into oxygen 38. ATP synthase is powered by the proton gradient created by the electron transport chain in mitochondria. What mechanism allows it to synthesize ATP? A. Rotation of its subunits by proton flow B. Oxidation of NADH C. Absorption of oxygen molecules D. Direct electron transfer to ADP 39. A committed step in a metabolic pathway ensures the pathway progresses to completion. Why is this step significant? A. It prevents substrates from exiting the pathway prematurely. B. It accelerates all following reactions. C. It allows flexibility for alternate pathways. D. It guarantees a steady energy output. 40. Glycolysis serves as a universal pathway for energy production and biosynthesis in cells. What makes it central to both aerobic and anaerobic organisms? A. Its ability to oxidize glucose fully B. Its role as a precursor to other pathways C. Its exclusive oxygen-dependence D. Its production of CO₂ directly V. Metabolic Pathways II 41. Carbohydrate metabolism begins with the breakdown of complex sugars into simple, soluble sugars during digestion. What enzyme in the mouth initiates this process by breaking down carbohydrates into monosaccharides? A. Lipase B. Salivary Amylase C. Protease D. Lactase 42. Glycolysis involves a series of enzymatic steps that convert glucose into pyruvate, generating ATP and NADH in the process. How many net ATP molecules are produced from one glucose molecule during glycolysis? A. 1 ATP B. 2 ATP C. 3 ATP D. 4 ATP 43. In aerobic respiration, pyruvate generated during glycolysis enters the Krebs cycle to produce high-energy molecules. Which of the following is NOT a product of the Krebs cycle? A. ATP B. NADH C. FADH₂ D. Oxygen 44. The electron transport chain (ETC) uses NADH and FADH₂ from earlier pathways to generate a proton gradient in mitochondria. What is the primary role of oxygen in the ETC? A. It acts as the initial electron donor. B. It serves as the final electron acceptor to form water. C. It transports protons across the membrane. D. It directly produces ATP. 45. During gluconeogenesis, glucose is synthesized from non-carbohydrate sources under conditions of fasting or low carbohydrate intake. Which organ is primarily responsible for this process? A. Brain B. Liver C. Heart D. Pancreas 46. Photosynthesis involves the conversion of light energy into chemical energy stored in glucose. What molecule is the primary pigment responsible for absorbing sunlight during this process? A. Carotenoids B. Chlorophyll C. Ribulose-1,5-bisphosphate D. Flavonoids 47. In the light-dependent reactions of photosynthesis, ATP and NADPH are generated to fuel the Calvin cycle. Which molecule is released as a by-product during the splitting of water in these reactions? A. Oxygen B. Carbon Dioxide C. Glucose D. Hydrogen Peroxide 48. Beta-oxidation involves the breakdown of fatty acids into acetyl-CoA, NADH, and FADH₂ for energy production. In which cellular organelle does beta-oxidation primarily occur? A. Cytoplasm B. Mitochondria C. Endoplasmic Reticulum D. Golgi Apparatus 49. Ketogenesis is a metabolic pathway activated during prolonged fasting or low carbohydrate intake. What are the primary products of ketogenesis used as an energy source by the brain and muscles? A. Fatty Acids B. Ketone Bodies C. Glucose D. Glycogen 50. Nitrogen metabolism involves the transformation of nitrogen into usable forms for organisms. What is the process called where atmospheric nitrogen (N₂) is converted into ammonia (NH₃)? A. Nitrification B. Nitrogen Fixation C. Denitrification D. Ammonification