Photosynthesis — Set 4
Biology · प्रकाश संश्लेषण · Questions 31–40 of 50
Photosynthesis is the primary process by which energy enters the?
Correct Answer: D. Biosphere
The biosphere includes all living organisms that rely on the organic matter produced by plants. Photosynthesis forms the base of almost every food chain on Earth. It is the fundamental link between solar energy and biological life.
The term 'Photolysis' refers to the splitting of which molecule?
Correct Answer: C. Water
Photolysis is the light-driven breakdown of water into protons, electrons, and oxygen. This step occurs in Photosystem II during the light-dependent stage. It is essential for providing the electrons that sustain the transport chain.
Which of the following is the main storage form of energy in plants?
Correct Answer: A. Starch
Starch is a complex carbohydrate made of thousands of glucose units. Plants store starch in organs like tubers, seeds, and fruits for future use. Iodine solution is commonly used in labs to detect the presence of starch.
Which organelle is specifically dedicated to the process of photosynthesis?
Correct Answer: D. Chloroplast
Chloroplasts contain the pigments and enzymes necessary for both light and dark reactions. They are thought to have originated from an ancient symbiotic relationship with cyanobacteria. These organelles are mostly found in the mesophyll cells of leaves.
Which wavelength of light has the highest energy for photosynthesis?
Correct Answer: C. Violet/Blue
Shorter wavelengths like blue and violet carry more energy than longer red wavelengths. Chlorophyll absorbs these high-energy waves effectively to power the photosynthetic process. Light quality is as important as light quantity for plant growth.
The primary objective of the Calvin cycle is to produce?
Correct Answer: A. G3P (Sugar)
The Calvin cycle uses chemical energy to synthesize three-carbon sugar molecules called G3P. These molecules are the precursors to glucose and all other organic plant compounds. This process represents the actual 'synthesis' part of photosynthesis.
Which of the following factors does NOT typically limit the rate of photosynthesis?
Correct Answer: D. Soil nitrogen
Soil nitrogen is a nutrient for growth but not a direct reactant in the photosynthetic chemical equation. The primary limiting factors are light, temperature, and carbon dioxide availability. When one of these is low, the overall rate of the process decreases.
Which type of plants are most common in temperate regions?
Correct Answer: A. C3 plants
C3 plants thrive in temperate environments where temperatures are moderate and water is sufficient. They make up about 85% of all plant species on Earth. Common examples include soybeans, rice, cotton, and most trees.
The oxygen concentration in the Earth's atmosphere is maintained primarily by?
Correct Answer: B. Photosynthesis
Photosynthesis is the only natural biological process that produces and releases oxygen. It offsets the oxygen consumed by animals and humans during cellular respiration. This balance is critical for the survival of all aerobic organisms.
Which pigment appears yellow and is often visible in autumn leaves?
Correct Answer: D. Xanthophyll
Xanthophylls are yellow pigments that are masked by green chlorophyll during the growing season. When chlorophyll breaks down in autumn, these yellow and orange pigments become visible. They play a role in light harvesting and protection from solar damage.