General
✓✗In mesophyll cells of C4 plants, the oxaloacetic acid formed is converted into other 4-carbon compounds such as
- malic acid or aspartic acid
- pyruvic acid or lactic acid
- citric acid or isocitric acid
- glycolate or glycine
General
✓✗The number of NADPH used to fix four molecules of CO2 in the Calvin cycle is
- 4
- 8
- 12
- 16
General
✓✗Which of the following pairs is INCORRECT?
- Carotenoids - protect chlorophyll from photo-oxidation
- Chlorophyll a - reaction centre pigment
- Chlorophyll b - blue-green band on chromatogram
- Xanthophylls - yellow band on chromatogram
General
✓✗Assertion (A): C4 plants show little or no photorespiration.
Reason (R): Decarboxylation of C4 acids raises the CO2 concentration around RuBisCO, so it acts mainly as a carboxylase.
Reason (R): Decarboxylation of C4 acids raises the CO2 concentration around RuBisCO, so it acts mainly as a carboxylase.
- Both A and R are true, and R is the correct explanation of A.
- Both A and R are true, but R is not the correct explanation of A.
- A is true but R is false.
- Both A and R are false.
General
✓✗In sugarcane, 14CO2 is fixed into malic acid. The enzyme that fixes CO2 here is
- ribulose phosphate kinase
- phosphoenol pyruvate carboxylase
- ribulose bisphosphate carboxylase
- fructose phosphatase
General
✓✗The first reaction of photorespiration is
- carboxylation
- oxygenation
- phosphorylation
- decarboxylation
General
✓✗The photochemical phase and the biosynthetic phase of photosynthesis take place, respectively, in the
- cytoplasm and chloroplast
- mitochondria and chloroplast
- thylakoids and stroma
- stroma and thylakoids
General
✓✗Water stress reduces photosynthesis mainly because it causes
- an increase in chlorophyll in the leaves
- opening of stomata, so more O2 is lost
- closure of stomata, so less CO2 enters
- faster carboxylation of RuBP in the stroma
General
✓✗The CF1 part of ATP synthase
- protrudes from the membrane into the stroma
- forms the proton channel across the membrane
- lies in the outer membrane of the chloroplast
- faces the thylakoid lumen and binds water
General
✓✗How many electrons must be removed from water to release one molecule of O2?
- 1
- 2
- 4
- 8
General
✓✗NADPH2 is generated through
- photosystem II
- anaerobic respiration
- photosystem I
- glycolysis
General
✓✗A student keeps an aquatic plant in water in bright light and counts the bubbles released. Which change would most reduce the number of bubbles?
- replacing the water with fresh pond water
- warming the water slightly from 15°C to 25°C
- adding a little sodium bicarbonate to the water
- moving the plant to dim light
General
✓✗The photochemical reactions in the chloroplast are directly involved in
- synthesis of glucose and its storage as starch
- formation of phosphoglyceric acid from RuBP
- photolysis of water and phosphorylation of ADP to ATP
- fixation of carbon dioxide by RuBisCO
General
✓✗The ATP formed in the light reaction is synthesised by
- RuBisCO
- PEP carboxylase
- ATP synthase
- NADP reductase
General
✓✗Which pigment is NOT a part of the light harvesting complex of thylakoids?
- chlorophyll a
- chlorophyll b
- phytochrome
- carotenoids