Plant Physiology Practice Questions

Correct answer: To produce food using sunlight

Photosynthesis is the process by which plants use sunlight, carbon dioxide, and water to produce glucose. This glucose serves as the primary source of food and energy for the plant.

Correct answer: Chlorophyll

Chlorophyll is the green pigment found in chloroplasts that absorbs light energy. It plays a central role in converting solar energy into chemical energy during photosynthesis.

Correct answer: Carbon dioxide

Plants absorb carbon dioxide from the atmosphere through tiny openings called stomata. This carbon dioxide is used to synthesize glucose during photosynthesis.

Correct answer: Stomata

Stomata are microscopic pores found mainly on leaves. They allow carbon dioxide to enter and oxygen and water vapor to leave the plant.

Correct answer: Xylem

Xylem is the vascular tissue that conducts water and dissolved minerals upward from the roots. It also provides structural support to the plant.

Correct answer: Phloem

Phloem transports sugars and other organic nutrients produced during photosynthesis. These nutrients are distributed to growing and storage tissues throughout the plant.

Correct answer: Transpiration

Transpiration is the evaporation of water from plant surfaces, mainly through stomata. It helps in cooling the plant and aids in water transport.

Correct answer: Transpiration

Transpiration creates a negative pressure or pull within the xylem. This transpiration pull helps draw water upward from the roots.

Correct answer: Glucose

Glucose is the immediate product of photosynthesis and serves as an energy source. Excess glucose may later be converted into starch for storage.

Correct answer: Auxin

Auxins promote cell elongation, especially in stems and shoots. They also play important roles in tropic responses and apical dominance.

Correct answer: Phototropism

Phototropism is the directional growth response of plant parts to light. Shoots generally exhibit positive phototropism by growing toward the light source.

Correct answer: Positive geotropism

Positive geotropism refers to growth in the direction of gravity. Roots exhibit this response by growing downward into the soil.

Correct answer: Respiration

Respiration breaks down glucose to release usable energy for cellular activities. This process occurs continuously in living plant cells.

Correct answer: Leaves

Leaves contain abundant chloroplasts and are well adapted to capture sunlight. Therefore, they are the primary sites of photosynthesis in most plants.

Correct answer: Light intensity

Light provides the energy required for photosynthesis. Increasing light intensity generally increases the rate of photosynthesis until another factor becomes limiting.

Correct answer: Absorbing water and minerals

Root hairs greatly increase the surface area available for absorption. They help plants efficiently take up water and dissolved minerals from the soil.

Correct answer: Ethylene

Ethylene is a gaseous plant hormone that accelerates fruit ripening. It also influences leaf fall and other developmental processes.

Correct answer: Translocation

Translocation is the transport of sugars and nutrients through the phloem. It distributes food from source tissues like leaves to sink tissues such as roots and fruits.

Correct answer: Oxygen gas

During photosynthesis, water molecules are split and oxygen is released into the atmosphere. This oxygen is essential for the survival of most living organisms.

Correct answer: To release energy from food

Photosynthesis produces food, while respiration breaks down that food to release energy. Plants require this energy for growth, maintenance, and other life processes.