🧬 Biochemistry Solved MCQs with Answers

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

1490 solved MCQs

In oxygenic photosynthesis, the electron donor isAnswer: Water The followings are the products of the light reactions of photosynthesis exceptAnswer: Glucose The vast majority of the molecules that act as energy carriers to power cellular activities are made inAnswer: The mitochondria and chloroplasts Which of the following statements about energy metabolism is false?Answer: Plants provide the water and CO2 that animals need to carry out respiration In cells having organelles, the steps of the Krebs cycle and the electron transport system occur in theAnswer: Mitochondria As a result of the photosynthetic process, which product is formed?Answer: Oxygen A eukaryotic cell that can carry out only fermentation instead of the complete aerobic respiration of glucoseAnswer: All of the above What is the maximum absorption wavelength for photosystem I in green plants?Answer: 700 nm Carbon dioxide is reduced inAnswer: The Calvin cycle During the light-dependent reactions of photosynthesis, which of the following does not occur?Answer: Carbon dioxide fixation Which of the following structures or processes are logically associated with chloroplasts?Answer: All of these In oxygenic photosynthesis, water is split in order to provide theAnswer: electrons needed to reduce P680 Where do the protons come from that make up the proton gradient used in the light reactions of photosynthesis?Answer: H₂O Oxidative phosphorylation is to respiration as __________ is to photosynthesisAnswer: Electron transport chain Which of the following serves as a reactant in photosynthesis and a product in cellular respiration?Answer: CO₂ Hydrogen (electron) acceptor in the light reactions isAnswer: NADP⁺ The cytochrome c oxidase complexAnswer: All of the above In the Calvin cycle, carbon dioxide is fixed in a reaction with theAnswer: Ribulose diphosphate What do NAD⁺, NADP⁺, and FAD⁺ all have in common?Answer: They are oxidized In noncyclic photophosphorylation, the ultimate acceptor of electrons that have been produced from the splitting of water isAnswer: Carbon dioxide The breakdown of glucose occurs by the process known asAnswer: Glycolysis The manufacture of ATP in both photosynthesis and respiration is made possible byAnswer: All of the above The end products of noncyclic photophosphorylation areAnswer: O₂, ATP and NADPH In algae, photosynthesis takes place inAnswer: Choloroplasts Which enzyme is involved in carbon-fixation reaction?Answer: Ribulose bisphosphate carboxylase Assume the combined processes of photosynthesis and cellular respiration, the electrons that start as part of HO at the beginning of the light reactions end up attaching toAnswer: O₂ to make new H₂O In the initial step of photosynthesis, sunlight energizes the electron pair ofAnswer: Chlorophyll pigments Rubisco (RuBP Carboxylase-oxygenase enzyme), glyceraldehyde 3-phosphate, and NADPH all play a role inAnswer: The dark reactions of photosynthesis The electrons that are released by the splitting of water during photosynthesis ultimately end up inAnswer: NADPH Glycolysis takes places in the __________ and produces __________ , which in the presence of oxygen then enters the __________ .Answer: cytosol; pyruvate; mitochondrion to complete cellular respiration