BIO 353 cell bio exam Practice Questions and Answers

BIO 353 cell bio exam Practice Questions and Answers The break down of glucose into pyruvate releases less than 25% of the total energy present in glucose. The remaining energy is stored in the resulting (2) pyruvate molecules. In the presence of oxygen, acting as an electron acceptor, complete substrate oxidation is possible. ______ is defined as "the oxidation driven flow of electrons, through or within a membrane, from reduced coenzymes to an electron acceptor, usually accompanied by the generation of ATP." The reduced cofactors crucial to electron transport are NADH and FADH2. - Ans:-Respiration Respiration has 4 stages ______ ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 2/110 Splits glucose into pyruvate, generates 2 and 2 NADH in the cytosol. The TCA cycle (Citric Acid Cycle or Crebs cycle) Oxidizes pyruvate to _____ in the mitochondrial matrix. Completely oxidizes acetyl CoA to ____. Conserves energy as reduced coenzyme molecules NADH, FADH2 (which have high energy electrons) Electron transport ____ and ____ donate and transfer electrons through a series of carriers to O^2 , releasing energy in each transfer step. The energy is used to actively transport or "pump" protons across a membrane to generate an ______ ____ gradient. ATP synthesis Uses the proton gradient as energy to drive ATP synthesis by ATP synthetase. - Ans:-Glycolysis ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 3/110 acetyl CoA NADH FADH2 electrochemical proton The Citric Acid or Tricarboxylic Acid or Krebs Cycle The cycle takes place in the _____ matrix. Pyruvates need to be actively transported (pumped) from the cytosol through mitochondrial inner membrane _____ then undergoes oxidative ______ to form acetyl-CoA. ___ NADH is also produced. The acetate group carried by CoA enters the cycle by being transferred to a 4-carbon dicarboxylic acid called ______ to make ____ ____ - a six-carbon tricarboxylic acid (TCA) (step 1). ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 4/110 •Citrate is then isomerized to isocitrate by the aconitase enzyme (step 2). •Steps 3 and 4 successive ___ ____ reactions follow. Each of which produces ____ reduced coenzyme ____ and releases one CO2, yielding a 4-carbon product bound to CoA (succinyl-Co-A). - Ans:- mitochondrial Pyruvate oxidative decarboxylation One oxaloacetate citric acid oxidative decarboxylation one NADH The Citric Acid Cycle ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 5/110 The free energy available in the thiolester bond of succinyl-Co-A is utilized to synthesize a ___ molecule (in plant cells - ATP is produced) (step 5). Succinate is oxidized to form fumarate. The oxidation to C=C (vs C=O) releases less energy, thus the lower energy ___ coenzyme (not NAD) is reduced ____ (step 6). Fumarate is hydrated to produce malate (step 7). Malate is oxidized to regenerate oxaloacetate yielding another _____ molecule (step 8). The oxaloacetate is now ready to react with a new acetyl-CoA to restart the cycle. - Ans:-GTP FAD FADH2 NADH ©GRACEAMELIA 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH OCTOBER 2024 Page 6/110 Net reaction for ___: Acetyl-CoA+ 3 NAD + FAD + ADP + PI- 2CO2+ 3 NADH + FADH2+CoASH+ ATP This stepwise oxidation of one molecule of pyruvate in the mitochondrion produces free energy that is conserved as ___ ATP, ____ NADH, and ___ FADH2 molecules. - Ans:-TCA one four one The TCA cycle enzymes are also regulated by _____ control. Note that the TCA Cycle is controlled by levels of ___ and ___ just like anaerobic glycolysis. - Ans:-allosteric