Which one of the following statements related to photosynthesis is NOT correct?
NAPDH is produced during carbon reactions by the enzymes present in stroma.
Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll pigment. This process occurs in two main stages: the light-dependent reactions and the light-independent reactions (also known as the carbon reactions or Calvin cycle).
Photosynthesis Stages and Locations
Let's understand where each part of photosynthesis happens and what molecules are involved:
- Light-dependent reactions: These reactions occur in the thylakoid membranes within the chloroplasts. Light energy is absorbed, and this energy is used to produce ATP and NADPH. Water is split in this process, releasing oxygen.
- Light-independent reactions (Carbon reactions): These reactions occur in the stroma, the fluid-filled space surrounding the thylakoids inside the chloroplasts. These reactions do not directly require light but use the ATP and NADPH produced during the light-dependent reactions to fix carbon dioxide from the atmosphere and convert it into glucose (sugar).
Analyzing Photosynthesis Statements
Let's evaluate each statement based on our understanding of photosynthesis:
- Light reaction takes place in the thylakoid membranes.
This statement is correct. The light-dependent reactions, or light reactions, occur on the thylakoid membranes where the pigments like chlorophyll are located to capture light energy.
- ATP and NADPH are produced in thylakoid membranes.
This statement is also correct. ATP and NADPH are the energy carriers and reducing power generated during the light-dependent reactions, which happen on the thylakoid membranes.
- Lumen is the enclosed interconnected region of the thylakoid membranes.
This statement is correct. The thylakoid membranes form sacs, and the space inside these sacs is called the lumen. These lumens are often interconnected, forming a continuous compartment within the chloroplast.
- NAPDH is produced during carbon reactions by the enzymes present in stroma.
This statement is incorrect. As discussed earlier, NADPH is produced during the light-dependent reactions, which take place in the thylakoid membranes. The carbon reactions (Calvin cycle), which occur in the stroma, *use* the NADPH produced in the light reactions as a reducing agent to convert carbon dioxide into carbohydrates. NADPH is consumed, not produced, during the carbon reactions.
Therefore, the statement that is NOT correct is that NADPH is produced during carbon reactions by enzymes in the stroma.
Important Questions from Photosynthesis
Kranz anatomy is found in _____ plant.
Which plant pigment is present in tomatoes?
Which one of the following reactions takes place during the reduction phase of the Calvin - Benson cycle?
The following statements were made with the assumption that the concentration of 3- phosphoglycerate is high inside chloroplasts of an actively photosynthesizing leaf.
A. There will be high concentration of triose phosphate in the chloroplast.
B. The activity of ADP-glucose pyrophosphorylase will be inhibited.
C. The carbon flow will be diverted from sucrose to starch.
D. Starch synthesis will be inhibited and carbon flow will be more towards sucrose synthesis.
Which one of the following combinations of above statements is correct?
The table below shows photosynthetic type, temperature and sunlight intensity levels.
Photosynthetic Type Temperature Sunlight Intensity A. C3 Plant i High P. High B. C4 plant ii Moderate Q. Moderate iii Low R Low Which of the following correctly matches the plant photosynthetic type with the temperature and sunlight conditions in which photosynthetic rate per unit leaf area is maximum for that plant?
