1. Cell Respiration and Photosynthesis
Higher Level
Topic 8

2. What you need to know

3. Cell Respiration 1
State that oxidation involves the loss of electrons from an element, whereas reduction involves a gain of electrons; and that oxidation frequently involves gaining oxygen or losing hydrogen, whereas reduction frequently involves losing oxygen or gaining hydrogen.
Outline the process of glycolysis, including phosphorylation, lysis, oxidation and ATP formation.
Draw and label a diagram showing the structure of a mitochondrion as seen in electron micrographs.

4. Cell Respiration 2
Explain aerobic respiration, including the link reaction, the Krebs cycle, the role of NADH + H+, the electron transport chain and the role of oxygen.
Explain oxidative phosphorylation in terms of chemiosmosis.
Explain the relationship between the structure of the mitochondrion and its function.

5. Photosynthesis 1
Draw and label a diagram showing the structure of a chloroplast as seen in electron micrographs.
State that photosynthesis consists of light-dependent and light-independent reactions.
Explain the light-dependent reactions.
Explain photophosphorylation in terms of chemiosmosis.

6. Photosynthesis 2 Explain the light-independent reactions.
Explain the relationship between the structure of the chloroplast and its function.
Explain the relationship between the action spectrum and the absorption spectrum of photosynthetic pigments in green plants.
Explain the concept of limiting factors in photosynthesis, with reference to light intensity, temperature and concentration of carbon dioxide.

7. One area In More detail

8. Limiting Factors In Photosynthesis 1
Light intensity, temperature, and carbon dioxide concentration can limit the rate of photosynthesis if they are below there optimum level. They are therefore called Limiting Factors
Under any combination of light intensity, temperature, and carbon dioxide concentration only one of the factors is actually limiting the rate of photosynthesis. This is the factor furthest from its optimum.

9. Limiting Factors In Photosynthesis 2
If the factor is changed to make it closer to the optimum then the rate of photosynthesis increases, but changing the other factors will have no effect as they are not the limiting factor.
A point will eventually be reached where this factor is no longer the limiting factor and a different factor becomes limiting
There can be points when two factors are equally close to their optimum and they are both limiting factors so increasing either of the two factors increases the rate of photosynthesis

10. questions

11. Which is not a product of the Krebs cycle?
A. CO2
B. NADH + H+
C. Pyruvate
D. ATP

12. Which way do the protons flow when ATP is synthesized in mitochondria?
A. From the inner matrix to the intermembrane space
B. From the intermembrane space to the inner matrix
C. From the intermembrane space to the cytoplasm
D. From the cytoplasm to the intermembrane space

13. How is the proton gradient generated in chloroplasts during photosynthesis?
A. Flow of electrons from carrier to carrier in the thylakoid membrane causes pumping of protons across the thylakoid membrane.
B. Light causes protons to flow through protein channels in the thylakoid membrane.
C. Light splits water molecules in the stroma, causing the release of protons.
D. Protons are pumped across the thylakoid membrane using energy from ATP.

14. Why is the action spectrum for photosynthesis similar to the absorption spectra of photosynthetic pigments?
A. Photosynthetic pigments have the same optimum temperature as the enzymes used in photosynthesis.
B. Plants absorb the same photosynthetic pigments for use in photosynthesis.
C. Only wavelengths of light absorbed by pigments can be used in photosynthesis.
D. The amount of energy absorbed by photosynthetic pigments is equal to the activation energy for photosynthesis.

15. Multiple Choice AnswersB A

16. Paper 2 Question
Explain how the light-independent reactions of photosynthesis rely on light-dependent reactions.

17. Markscheme
light-independent reaction fixes CO2; to make glycerate 3-phosphate; glycerate 3-phosphate / GP / phosphoglyceric acid becomes reduced; to triose phosphate / phosphoglyceraldehyde / glyceraldehyde 3-phosphate; using NADPH; using ATP; ATP needed to regenerate RuBP; ATP is made in light-dependent reactions; light causes photoactivation / excitation of electrons; flow of electrons causes pumping of protons into thylakoid; ATP formation when protons pass back across thylakoid membrane; electrons are passed to NADP/NADP+; NADPH produced in the light dependent reactions;