Online Test — Photosynthesis in Higher Plants
15 Questions • 15 min • Chapter MCQ
15:00
Question 1 of 15
Photosynthesis takes place mainly in the:
Mitochondria
Chloroplasts
Nucleus
Ribosomes
Explanation: Chloroplasts are the site of photosynthesis.
Question 2 of 15
The main photosynthetic pigment is:
Chlorophyll a
Carotene
Xanthophyll
Anthocyanin
Explanation: Chlorophyll a is the main pigment; others are accessory pigments.
Question 3 of 15
The light reaction occurs in the:
Stroma
Thylakoid membranes
Cell wall
Vacuole
Explanation: The light reaction happens in the thylakoid membranes.
Question 4 of 15
Splitting of water in the light reaction is called:
Hydrolysis
Photolysis
Glycolysis
Photorespiration
Explanation: Photolysis splits water, releasing oxygen.
Question 5 of 15
The oxygen released in photosynthesis comes from:
CO₂
Water
Glucose
ATP
Explanation: Oxygen comes from the photolysis of water.
Question 6 of 15
The two energy-rich products of the light reaction are:
Glucose and oxygen
ATP and NADPH
CO₂ and water
Starch and protein
Explanation: The light reaction makes ATP and NADPH (assimilatory power).
Question 7 of 15
The dark reaction (Calvin cycle) occurs in the:
Thylakoid membranes
Stroma
Nucleus
Mitochondria
Explanation: The Calvin cycle takes place in the stroma.
Question 8 of 15
The CO₂-fixing enzyme of the Calvin cycle is:
RuBisCO
Nitrogenase
Catalase
Lipase
Explanation: RuBisCO fixes CO₂ onto RuBP.
Question 9 of 15
In C3 plants, the first stable product of CO₂ fixation has:
2 carbons
3 carbons
4 carbons
5 carbons
Explanation: C3 plants form a 3-carbon compound (3-PGA) first.
Question 10 of 15
Which of these is a C4 plant?
Wheat
Rice
Maize
Pea
Explanation: Maize (and sugarcane) are C4 plants.
Question 11 of 15
The special leaf anatomy of C4 plants is called:
Kranz anatomy
Dorsiventral anatomy
Isobilateral anatomy
Secondary growth
Explanation: C4 plants show Kranz anatomy with bundle-sheath cells.
Question 12 of 15
The wasteful side reaction of RuBisCO largely avoided by C4 plants is:
Photolysis
Photorespiration
Transpiration
Respiration
Explanation: C4 plants concentrate CO₂ and avoid photorespiration.
Question 13 of 15
In nature, the factor that most often limits photosynthesis is:
Carbon dioxide
Oxygen
Nitrogen
Soil colour
Explanation: CO₂ is usually the main limiting factor in natural conditions.
Question 14 of 15
According to Blackman's law, the rate is determined by the factor that is:
In shortest supply
In greatest supply
Most colourful
Largest
Explanation: The limiting factor (in shortest supply) sets the rate.
Question 15 of 15
The rate of photosynthesis falls at very high temperatures because:
Light increases
Enzymes are denatured
CO₂ disappears
Water freezes
Explanation: High heat denatures the enzymes controlling photosynthesis.