Lecture 6: Anaerobic Respiration and Photosynthesis

Question 1

Describe Anaerobic Respiration.

Answer 1

1. Glycolysis occurs.
2. Pyruvate, NADH, and ATP are produced.
3. Pyruvate gets reduced to lactate, and NADH gets oxidized to NAD+.
4. NAD+ is consumed for glycolysis to generate more ATP.
5. Lactate from pyruvate becomes the input for the Anaerobic respiration’s ETC.
6. Lactate gets oxidized to Pyruvate and NADH, and its electrons get passed onto the final electron acceptor SO4 -2.

Question 2

Describe the Light reactions in Photosynthesis.

Answer 2

1. Pigments absorb light in the light-harvesting complex of PSII.
2. Energy is transferred to P680, chlorophyll molecule, through resonance.
3. P680 is excited to P680+, and oxidizes H2O.
4. H2O transfers it’s electrons to P680+ to make it P680.
5. The electrons obtained by P680 in PSII are transferred to PSI and P700. They are further excited by the light absorbed by the pigments in the light-harvesting complex of PSI and transferred to P700 through resonance.

*The transfer of electrons from one PS to another creates a proton gradient that generates ATP. This process is called photophosphorylation.

6. The electrons are then transferred to NADP+ and NADP+ gets reduced to NADPH.

Question 3

Describe the Calvin cycle in photosynthesis.

Answer 3

1. RuBP phosphorylates R5P.
2. CO2 reacts with RuBP to form 2 3PG molecules/
3. One 3PG molecule is used to make glucose. The other 3PG molecule gets phosphorylated to make BPG.
4. BPG is reduced to G3P.
5. G3P regenerates R5P.