Photosynthesis | OCR A-Level Biology A (H420)
Photosynthesis
- 58 questions
- 5 subtopics
- Module 5: Communication, homeostasis and energy
- Component 01 and Component 03
Photosynthesis is the sixth section of Module 5.
It covers the structure of the chloroplast and where each stage happens, the pigments and how chromatography separates them, the light-dependent reactions and photophosphorylation, the Calvin cycle, and the factors that limit the rate.
Sample questions from Photosynthesis
Answer each one closed book first, then open the answer.
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Photosynthesis and chloroplast structure
What structure surrounds the chloroplast?
Show the answer
The chloroplast is surrounded by a double membrane (an outer and an inner membrane) called the envelope. -
Photosynthesis and chloroplast structure
Where in the chloroplast does the light-dependent stage of photosynthesis occur?
Show the answer
The light-dependent stage occurs on the thylakoid membranes. -
Photosynthetic pigments and chromatography
What are photosystems?
Show the answer
Photosystems are protein complexes containing pigments that absorb light and initiate electron transfer. -
Photosynthetic pigments and chromatography
State the formula for calculating Rꜰ value.
Show the answer
Rꜰ = distance travelled by pigment ÷ distance travelled by solvent front. -
The light-dependent stage
Which photosystems are involved in non-cyclic photophosphorylation, and what are its products?
Show the answer
Non-cyclic photophosphorylation involves both photosystem I and photosystem II and produces ATP, reduced NADP and oxygen. -
The light-dependent stage
What happens to excited electrons in cyclic photophosphorylation?
Show the answer
Excited electrons return to photosystem I after passing through electron carriers. -
The Calvin cycle
What enzyme catalyses the fixation of carbon dioxide to RuBP?
Show the answer
Ribulose bisphosphate carboxylase (RuBisCO). -
The Calvin cycle
Can triose phosphate be used to synthesise lipids?
Show the answer
Yes, triose phosphate can be used as a starting material for the synthesis of lipids.
The 5 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Photosynthesis and chloroplast structure | The raw materials and products and how they mirror respiration, and the envelope, grana, thylakoids and stroma with the stage that happens in each. | 14 |
| Photosynthetic pigments and chromatography | What photosystems and light harvesting systems do, and how thin layer chromatography separates the pigments, with the Rf calculation. | 8 |
| The light-dependent stage | What happens to an electron when a pigment absorbs light, non-cyclic and cyclic photophosphorylation, and the three things the photolysis of water provides. | 10 |
| The Calvin cycle | Carbon dioxide fixation onto RuBP by rubisco, the conversion of glycerate 3-phosphate to triose phosphate, and what the triose phosphate goes on to build. | 8 |
| Limiting factors | Light intensity, carbon dioxide concentration, temperature and water stress, what each does to GP, RuBP and TP levels, and the inverse square law. | 18 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
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Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby sections
OCR A-Level Biology A Active Recall Guide
Every section, not just this one. 1,833 questions with their answers.