Topic 13: Photosynthesis Flashcards
Definitions I:
(a) Photosynthesis
(b) Chloroplast
(c) Thylakoid
(a) Photosynthesis: Light-driven synthesis of glucose. (1 mark)
(b) Chloroplast: Organelle for photosynthesis. (1 mark)
(c) Thylakoid: Membrane site of light reactions. (1 mark)
Relate chloroplast structure to function in a spinach leaf cell. [3 Marks]
Grana thylakoids host light reactions (1 mark); Stroma for Calvin cycle (1 mark); Envelope isolates processes (1 mark). (3 marks)
In a wheat leaf, explain how ATP and reduced NADP drive the Calvin cycle. [2 Marks]
ATP powers Calvin cycle reactions (1 mark); Reduced NADP reduces GP to TP (1 mark). (2 marks)
State the sites of light-dependent and light-independent stages in a pea chloroplast. [2 Marks]
Light-dependent: Thylakoids in grana (1 mark); Light-independent: Stroma (1 mark). (2 marks)
Describe the role of chlorophyll a and carotene in a bean thylakoid. [2 Marks]
Chlorophyll a absorbs red/blue light (1 mark); Carotene absorbs blue, aids energy transfer (1 mark). (2 marks)
Interpret the absorption spectrum of chlorophyll b in a lab study. [2 Marks]
Peaks at blue/red wavelengths (1 mark); Shows light absorption for photosynthesis (1 mark). (2 marks)
In a classroom, use chromatography to separate chloroplast pigments from spinach. [3 Marks]
Crush spinach, run chromatography (1 mark); Bands show pigments, Rf identifies (1 mark); E.g., chlorophyll a (1 mark). (3 marks)
Explain cyclic photophosphorylation in a lettuce chloroplast. [3 Marks]
PSI photoactivates chlorophyll (1 mark); Electrons cycle, release energy (1 mark); ATP synthesised (1 mark). (3 marks)
In a maize leaf, explain non-cyclic photophosphorylation. [4 Marks]
PSI and PSII photoactivate (1 mark); Water splits, O₂ released (1 mark); ATP forms (1 mark); NADP reduced (1 mark). (4 marks)
Describe energy transfer in photophosphorylation in a sunflower thylakoid. [3 Marks]
Electrons energise chain (1 mark); Protons pumped across thylakoid (1 mark); ATP synthase uses proton flow (1 mark). (3 marks)
Outline the Calvin cycle stages in a rice stroma. [4 Marks]
Rubisco fixes CO₂ to RuBP, forms GP (1 mark); GP reduced to TP (1 mark); TP regenerates RuBP (1 mark); Uses ATP/NADP (1 mark). (4 marks)
State how Calvin cycle intermediates form organic molecules in a tomato plant. [2 Marks]
GP forms amino acids (1 mark); TP makes carbs, lipids, amino acids (1 mark). (2 marks)
In an algal bloom, explain how light intensity affects photosynthesis rate. [2 Marks]
Low light limits rate (1 mark); High light increases until saturation (1 mark). (2 marks)
Using DCPIP, investigate light wavelength’s effect on spinach chloroplast photosynthesis. [3 Marks]
Mix chloroplasts, DCPIP, vary wavelength (1 mark); Blue/red decolourise fastest (1 mark); Measures reduction rate (1 mark). (3 marks)
In a pond, measure photosynthesis rate in Elodea with varying CO₂ levels. [3 Marks]
Bubble count in Elodea, vary CO₂ (1 mark); Rate rises with CO₂ (1 mark); Plateaus at optimum (1 mark). (3 marks)
Analyse how temperature limits photosynthesis in a greenhouse tomato plant. [4 Marks]
Low temp slows enzymes (1 mark); Optimum boosts rate (1 mark); High temp denatures proteins (1 mark); Limits photosynthesis (1 mark). (4 marks)
