Prepare for NEET Biology Photosynthesis in Higher Plants with MCQs & PYQs on NEET.GUIDE. Get free practice, previous year questions, and expert guidance to grasp light and dark reactions.
A researcher is studying a C4 plant under controlled conditions. They suddenly increase the oxygen concentration in the environment while maintaining constant light and CO2 levels. Which of the following is the MOST likely immediate consequence?
A significant decrease in the rate of photosynthesis
A slight increase in photorespiration
A significant increase in the rate of photosynthesis
No change in the rate of photosynthesis or photorespiration
A plant is exposed to an environment with high CO2 and low O2 concentrations. Which process would be MOST directly and significantly inhibited under these conditions?
Calvin cycle
Photorespiration
Electron transport chain
C4 cycle
A scientist isolates chloroplasts and provides them with in the dark. After a brief period, the is found predominantly in:
RuBP
3-PGA
Glucose
Triose phosphate
If a plant is exposed to in the dark and then transferred to light, the label will appear first in which of the following carbohydrates?
Starch
Sucrose
Triose phosphates (glyceraldehyde-3-phosphate and dihydroxyacetone phosphate)
Fructose-1,6-bisphosphate
Under conditions of high temperature and drought stress, a plant closes its stomata to conserve water. Which of the following is the MOST DIRECT consequence on the Calvin cycle?
Increased photorespiration due to oxygen accumulation.
Enhanced ATP synthesis due to increased proton gradient.
Reduced availability of CO2 limits carboxylation, leading to a decrease in RuBP regeneration.
Increased activity of Rubisco due to higher substrate concentration.
Which of the following combinations of factors would MOST SIGNIFICANTLY limit the rate of photosynthesis in a typical C3 plant?
Low light intensity, high CO2 concentration, and optimal temperature
High light intensity, low O2 concentration, and high humidity
High temperature, low CO2 concentration, and water stress
Low temperature, high CO2 concentration, and waterlogged soil
A mutation affects a plant's ability to synthesize carotenoids. Which of the following would be the MOST LIKELY consequence for photosynthesis under high light intensity?
Enhanced light absorption and increased photosynthetic rate.
Increased damage to chlorophyll and photosystems due to excessive light energy.
No significant change in photosynthetic rate or chlorophyll integrity.
Shift in the absorption spectrum towards longer wavelengths.
During cyclic photophosphorylation, electrons from Photosystem I are ultimately accepted by:
NADP+
Photosystem II
Photosystem I
Water
If a herbicide specifically inhibits the plastoquinone binding site of Photosystem II, which of the following would be the most immediate consequence?
Increased ATP production
Accumulation of NADPH
Cessation of electron flow from water to Photosystem II
Enhanced cyclic photophosphorylation
Under conditions of high light intensity and limited CO2 availability, which process is most likely to be favored in chloroplasts?
Enhanced Calvin cycle activity
Increased non-cyclic photophosphorylation
Photorespiration
Increased synthesis of chlorophyll
