Year 13 - Respiration Flashcards
1
Q
Describe the stages of glycolysis in aerobic respiration
A
In the cytoplasm of cells:
- Glucose is phosphorylated to glucose phosphate using 2 ATP molecules.
- Glucose phosphate splits into two triose phosphate
- Dehydrogenase catalyses the oxidation of Triose phosphate into pyruvate with a net gain of 2 ATP and a reduced NAD.
2
Q
Describe the stages of the link reaction in aerobic respiration.
A
Pyruvate is actively transported into the mitochondrial matrix.
- Dehydrogenase catalyses oxidation of pyruvate (3C) into acetate (2C), producing reduced NAD.
- Decarboxylase catalyses loss of carbon dioxide in the process.
- Acetate combines with coenzyme A to produce acetylcoenzyme A
- Acetylcoenzyme A reacts with a four-carbon molecule, releasing coenzyme A and producing a 6C molecule that enters the krebs cycle.
3
Q
Describe the stages of the krebs cycle in aerobic respiration
A
For both acetylcoenzyme A (from one glucose) in the matrix:
- Acetylcoenzyme A reacts with a four-carbon molecule, releasing coenzyme A and producing a 6C molecule.
- Dehydrogenase catalyses the oxidation of 6C molecule producing reduced NAD.
- Decarboxylase catalyses the loss of CO2 in the process.
- Dehydrogenase catalyses the oxidation of 5C molecule producing 2 reduced NAD and reduced FAD.
- Decarboxylase catalyses the loss of CO2 in the process.
- ATP generated by substrate-level phosphorylation.
4
Q
Describe the stages of oxidative phosphorylation in aerobic
respiration
A
Chemiosmotic theory at inner mitochondrial membrane:
- reduced NAD and reduced FAD release electrons to electron transfer chain (ETC)
- Electrons pass through ETC by a series of redox reactions.
- Energy released used to pump H+ (protons) across inner mitochondrial membrane into intermembrane space.
- H+ ions diffuse down electrochemical gradient, through ATP synthase embedded in the membrane, back into the matrix.
- ATP synthase catalyses ATP by condensing ADP and Pi in oxidative phosphorylation.
- O2 acts a terminal electron acceptor from ETC producing water
5
Q
Describe anaerobic respiration in humans
A
- Glucose is phosphorylated to glucose phosphate using 2 ATP molecules.
- Glucose phosphate splits into two triose phosphate
- Dehydrogenase catalyses the oxidation of Triose phosphate into pyruvate with a net gain of 2 ATP and a reduced NAD.
-Pyruvate reduced by NADH to lactate.
-this regenerates NAD.
-NAD used in glycolysis
6
Q
Describe anaerobic respiration in yeast/plants/ microbes
A
- Glucose is phosphorylated to glucose phosphate using 2 ATP molecules.
- Glucose phosphate splits into two triose phosphate
- Dehydrogenase catalyses the oxidation of Triose phosphate into pyruvate with a net gain of 2 ATP and a reduced NAD.
-Pyruvate reduced by NADH to ethanol and CO2.
-this regenerates NAD.
-NAD used in glycolysis
