🧬 Biochemistry Solved MCQs with Answers

Practice 1490 approved 🧬 Biochemistry questions with verified answers from the 🧬 Medical Science subject for Pakistan exams.

1490 solved MCQs

What process in cellular respiration is essentially the reverse of carbon fixation in photosynthesis?Answer: Citric acid cycle What do coenzyme A, CO₂, oxaloacetate, and FADH₂ all have in common?Answer: They are all components or products of the citric acid cycle If the oxygen is labeled in CO₂ and provide this CO₂ to a plant, where it is expected to find this labeled oxygen after the plant had undergone photosynthesis?Answer: In the carbohydrate produced FAD is reduced to FADH₂ duringAnswer: Krebs cycle During glycolysis, electrons removed from glucose are passed toAnswer: NAD⁺ A biological redox reaction always involvesAnswer: All of the above Coenzyme Q is involved in electron transport asAnswer: A lipid-soluble electron carrier The carbon dioxide is primary a product ofAnswer: Krebs cycle Which of the following is not a feature of oxidative phosphorylation?Answer: Direct transfer of phosphate from a substrate molecule to ADP Which of the following is not a significant biological oxidizing agent?Answer: Fe³⁺ How many CO₂ molecules are exhaled for each O₂ molecule utilized in cellular respiration?Answer: 1 What happens after glycolysis when oxygen is available as an electron acceptor?Answer: NADH is produced Lactic acid is produced by human muscles during strenuous exercise because of lack ofAnswer: Oxygen Which of the following is correct sequence of processes in the oxidation of glucose?Answer: Glycolysis - Krebs cycle - eletron transport In electron transport, electrons ultimately pass toAnswer: oxygen The complete oxidation of glucose yields usable energy in the form ofAnswer: ATP During electron transport, protons are pumped out of the mitochondrion at each of the major sites except forAnswer: complex II The aerobic breakdown of glucose known as respiration involvesAnswer: All of the above In aerobic respiration, the compound that enters a mitochondrion isAnswer: Pyruvate How many molecules of ATPs are synthesized per NADH oxidation?Answer: 3 Why is the TCA cycle the central pathway of metabolism of the cell?Answer: Its intermediates are commonly used by other metabolic reactions In what form does the product of glycolysis enter the TCA cycle?Answer: AcetylCoA Malate-asparatate shuttle operates inAnswer: Heart and liver Oxidation of a molecule involvesAnswer: Loss of electron During cellular respiration, most of the ATP made, is generated byAnswer: Oxidative phosphorylation Important function of cholesterol is toAnswer: Modulate fluidity To stop ATP synthesis which chemical is generally used?Answer: 2,4 dinitrophenol The enzymes of the TCA cycle in a eukaryotic cell are located in theAnswer: Mitochondria Citric acid cycle occurs inAnswer: Mitochondria Most multi-cellular organisms obtain energy for the synthesis of ATP during oxidative phosphorylation fromAnswer: A proton gradient across the inner mitochondrial membrane