The table below shows photosynthetic type, temperature and sunlight intensity levels. 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?Photosynthetic Type Temperature Sunlight Intensity A. C3 Plant i High P. High B. C4 plant ii Moderate Q. Moderate iii Low R Low
Photosynthetic Plant Types and Conditions
Photosynthesis is the process by which plants convert light energy into chemical energy in the form of glucose. Different types of plants have adapted different photosynthetic pathways to thrive in specific environmental conditions, primarily related to temperature and light intensity. The two main types discussed here are C3 plants and C4 plants.
C3 Photosynthesis Efficiency
C3 plants are the most common type, including crops like wheat, rice, and soybeans. Their photosynthetic pathway, known as the Calvin cycle, directly fixes carbon dioxide into a three-carbon compound. C3 photosynthesis is generally more efficient under moderate temperature and moderate light intensity. At high temperatures, C3 plants experience a process called photorespiration, which reduces their photosynthetic efficiency. Their photosynthetic rate typically saturates at lower light intensities compared to C4 plants.
C4 Photosynthesis Efficiency
C4 plants, such as maize, sugarcane, and millet, have evolved a mechanism that minimizes photorespiration and increases water use efficiency, especially in hot and dry environments. They first fix carbon dioxide into a four-carbon compound in mesophyll cells, which is then transported to bundle sheath cells where CO2 is released and enters the Calvin cycle. This CO2 concentration mechanism allows C4 plants to maintain high photosynthetic rates even at high temperatures and high light intensities, conditions where C3 plants become less efficient.
Matching Photosynthetic Types to Optimal Conditions
Based on the characteristics of C3 and C4 plants:
- For C3 plants (A), the maximum photosynthetic rate per unit leaf area is typically observed under moderate temperature (ii) and moderate sunlight intensity (Q).
- For C4 plants (B), the maximum photosynthetic rate per unit leaf area is typically observed under high temperature (i) and high sunlight intensity (P).
Let's look at the given table and options:
| Photosynthetic Type | Temperature | Sunlight Intensity |
|---|---|---|
| A. C3 Plant | i High | P. High |
| B. C4 plant | ii Moderate | Q. Moderate |
| iii Low | R Low |
Matching the plant type with its optimal conditions from the table:
- C3 Plant (A) matches with moderate temperature (ii) and moderate sunlight intensity (Q). This gives the combination A - ii - Q.
- C4 plant (B) matches with high temperature (i) and high sunlight intensity (P). This gives the combination B - i - P.
Therefore, the correct matching is A - ii - Q; B - i - P.
Important Questions from Photosynthesis
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?
Calvin-Benson cycle is divided into three phases, namely carboxylation, reduction and regeneration. The following statements are related to the three phases of Calvin-Benson cycle:
A. The product of light reaction, ATP and NADPH is utilized in the carboxylation phase.
B. Six molecules of 3-phosphoglycerate is converted into six molecules of glyceraldehyde 3-phosphate in the reduction phase.
C. The action of aldolase enzyme for the production of fructose 1, 6-bisphosphate takes place in reduction phase.
D. Formation of seven carbon compound, sedoheptulose-7- phosphate takes place in the regeneration phase.
Which one of the following combinations is correct?
Which one of the following metabolites formed during Calvin-Benson cycle in chloroplast is involved in starch biosynthesis and can also be transported to cytosol?
Following are certain statements regarding C2, C3, C4 and CAM carbon metabolism in plants.
A. In C3 cycle, one molecule of 3-phosphoglycerate formed during carboxylation phase is utilized for the biosynthesis of sugars, fatty acid and amino acids.
B. During C2 cycle glycine is transported from peroxisome to mitochondria and glycerate is transported from peroxisome to chloroplast.
C. The concentration of CO2 in bundle sheath of C4 plants is several fold lower than the external atmosphere.
D. The stomata of CAM plants open at night.
Which one of the following combination of statements is correct?
