Back to the full dot-point answer
VICBiologyQuick questions
Unit 3: How do cells maintain life?
Quick questions on Cellular respiration (glycolysis, Krebs cycle, electron transport chain): VCE Biology Unit 3
15short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is glycolysis (cytosol)?Show answer
Location. The cytosol of every living cell.
What is link reaction (mitochondrial matrix)?Show answer
If oxygen is present, each pyruvate enters the mitochondrial matrix and is converted to acetyl-CoA (2 carbons), releasing one CO2 and producing one NADH. Two pyruvates per glucose therefore yield 2 acetyl-CoA, 2 CO2 and 2 NADH.
What is krebs cycle (mitochondrial matrix)?Show answer
Location. Mitochondrial matrix.
What is electron transport chain and oxidative phosphorylation (inner mitochondrial membrane)?Show answer
Location. Inner mitochondrial membrane (folded into cristae).
What is anaerobic respiration (cytosol)?Show answer
If oxygen is absent, the electron transport chain stalls. NADH cannot be reoxidised to NAD+, so glycolysis would also stall. Fermentation regenerates NAD+ in the cytosol so glycolysis can continue producing 2 ATP per glucose.
What is location?Show answer
The cytosol of every living cell.
What is inputs?Show answer
One glucose, 2 ATP (investment phase), 4 ADP + Pi, 2 NAD+.
What is outputs?Show answer
2 pyruvate (3 carbons each), 2 NADH, net 2 ATP (4 made, 2 invested).
What is process?Show answer
Glucose (6 carbons) is phosphorylated twice using 2 ATP, split into two 3-carbon intermediates, and oxidised. NAD+ accepts electrons and H+ to form NADH. ADP is phosphorylated to ATP by substrate-level phosphorylation.
What is per glucose?Show answer
4 CO2, 6 NADH, 2 FADH2, 2 ATP.
What is animal cells?Show answer
Pyruvate is reduced to lactate (lactic acid) by lactate dehydrogenase. NADH is reoxidised to NAD+. No CO2 is released.
What is plant and yeast cells?Show answer
Pyruvate is decarboxylated to acetaldehyde (releasing CO2), then reduced to ethanol by alcohol dehydrogenase. NADH is reoxidised to NAD+. This is the basis of brewing and bread-making.
What is saying glycolysis occurs in the mitochondrion?Show answer
It happens in the cytosol.
What is forgetting the link reaction?Show answer
Pyruvate must be converted to acetyl-CoA before it enters the Krebs cycle. This step releases CO2 and produces NADH.
What is calling oxidative phosphorylation "the Krebs cycle"?Show answer
Oxidative phosphorylation is the ATP synthesis on the inner mitochondrial membrane, driven by the chemiosmotic gradient. The Krebs cycle is a separate matrix process whose main job is generating NADH and FADH2.