EXSS 256 Metabolism and Endocrine Systems |
Complete Exam | Practice Questions, Answers &
Detailed Rationales
2026-2027
,[METABOLISM] Metabolism The sum of all chemical reactions in the body.
[METABOLISM] Catabolism Breakdown of complex molecules into simpler ones; exergonic and releases energy.
[METABOLISM] Anabolism Building complex molecules from simpler ones; endergonic and requires energy.
[METABOLISM] Exergonic reaction A reaction that releases energy; associated with catabolism.
[METABOLISM] Endergonic reaction A reaction that requires/consumes energy; associated with anabolism.
[METABOLISM] ATP The cell's immediately usable chemical-energy currency.
[METABOLISM] Oxidation Removal/loss of electrons.
[METABOLISM] Reduction Addition/gain of electrons.
[METABOLISM] Redox reaction A coupled reaction in which one molecule is oxidized and another is reduced.
[METABOLISM] Glycolysis Glucose is broken down into 2 pyruvate molecules.
[METABOLISM] Where does glycolysis occur? In the cytosol.
[METABOLISM] Starting molecule of glycolysis One 6-carbon glucose.
[METABOLISM] End product of glycolysis Two 3-carbon pyruvate molecules.
[METABOLISM] Net ATP from glycolysis 2 ATP net.
[METABOLISM] ATP accounting in glycolysis 2 ATP are invested and 4 ATP are produced, giving a net of 2.
, [METABOLISM] Does glycolysis require oxygen? No. Glycolysis can occur with or without oxygen.
[METABOLISM] Speed/yield of glycolysis Fast ATP production but low ATP yield.
[METABOLISM] Major rate-regulating enzyme in glycolysis PFK (phosphofructokinase).
[METABOLISM] What stimulates PFK/glycolysis? Low-energy signals such as ADP and AMP.
[METABOLISM] What inhibits PFK/glycolysis? High-energy signals such as ATP and citrate.
[METABOLISM] Hexokinase role Helps trap glucose in the cell by converting it to glucose-6-phosphate.
[METABOLISM] LDH Lactate dehydrogenase; converts pyruvate to lactate.
[METABOLISM] When is pyruvate converted to lactate? When oxygen availability is insufficient or glycolytic demand is very high.
[METABOLISM] PDH Pyruvate dehydrogenase; converts pyruvate to Acetyl-CoA for aerobic metabolism.
[METABOLISM] Pyruvate fate with low oxygen Pyruvate → lactate via LDH.
[METABOLISM] Pyruvate fate with adequate oxygen Pyruvate → Acetyl-CoA via PDH.
[METABOLISM] Big glucose breakdown pathway Glucose → glycolysis → pyruvate → Acetyl-CoA → Krebs cycle → ETC.
[METABOLISM] Acetyl-CoA A central metabolic molecule that links carbohydrate, fat, and some amino-acid
metabolism.
[METABOLISM] Why is Acetyl-CoA called a central Carbohydrates, fatty acids, and certain amino acids can feed into Acetyl-CoA or
molecule? related pathways before Krebs/ETC.
[METABOLISM] What happens to Acetyl-CoA aerobically? It enters the Krebs cycle.
Complete Exam | Practice Questions, Answers &
Detailed Rationales
2026-2027
,[METABOLISM] Metabolism The sum of all chemical reactions in the body.
[METABOLISM] Catabolism Breakdown of complex molecules into simpler ones; exergonic and releases energy.
[METABOLISM] Anabolism Building complex molecules from simpler ones; endergonic and requires energy.
[METABOLISM] Exergonic reaction A reaction that releases energy; associated with catabolism.
[METABOLISM] Endergonic reaction A reaction that requires/consumes energy; associated with anabolism.
[METABOLISM] ATP The cell's immediately usable chemical-energy currency.
[METABOLISM] Oxidation Removal/loss of electrons.
[METABOLISM] Reduction Addition/gain of electrons.
[METABOLISM] Redox reaction A coupled reaction in which one molecule is oxidized and another is reduced.
[METABOLISM] Glycolysis Glucose is broken down into 2 pyruvate molecules.
[METABOLISM] Where does glycolysis occur? In the cytosol.
[METABOLISM] Starting molecule of glycolysis One 6-carbon glucose.
[METABOLISM] End product of glycolysis Two 3-carbon pyruvate molecules.
[METABOLISM] Net ATP from glycolysis 2 ATP net.
[METABOLISM] ATP accounting in glycolysis 2 ATP are invested and 4 ATP are produced, giving a net of 2.
, [METABOLISM] Does glycolysis require oxygen? No. Glycolysis can occur with or without oxygen.
[METABOLISM] Speed/yield of glycolysis Fast ATP production but low ATP yield.
[METABOLISM] Major rate-regulating enzyme in glycolysis PFK (phosphofructokinase).
[METABOLISM] What stimulates PFK/glycolysis? Low-energy signals such as ADP and AMP.
[METABOLISM] What inhibits PFK/glycolysis? High-energy signals such as ATP and citrate.
[METABOLISM] Hexokinase role Helps trap glucose in the cell by converting it to glucose-6-phosphate.
[METABOLISM] LDH Lactate dehydrogenase; converts pyruvate to lactate.
[METABOLISM] When is pyruvate converted to lactate? When oxygen availability is insufficient or glycolytic demand is very high.
[METABOLISM] PDH Pyruvate dehydrogenase; converts pyruvate to Acetyl-CoA for aerobic metabolism.
[METABOLISM] Pyruvate fate with low oxygen Pyruvate → lactate via LDH.
[METABOLISM] Pyruvate fate with adequate oxygen Pyruvate → Acetyl-CoA via PDH.
[METABOLISM] Big glucose breakdown pathway Glucose → glycolysis → pyruvate → Acetyl-CoA → Krebs cycle → ETC.
[METABOLISM] Acetyl-CoA A central metabolic molecule that links carbohydrate, fat, and some amino-acid
metabolism.
[METABOLISM] Why is Acetyl-CoA called a central Carbohydrates, fatty acids, and certain amino acids can feed into Acetyl-CoA or
molecule? related pathways before Krebs/ETC.
[METABOLISM] What happens to Acetyl-CoA aerobically? It enters the Krebs cycle.
