Q1. What is the primary mode of nutrition in most plants?
a) Heterotrophic
b) Autotrophic
c) Saprotrophic
d) Parasitic
Show Answer
Correct Answer: b) Autotrophic
Explanation: Most plants are autotrophic, meaning they produce their own food through the process of photosynthesis. They use sunlight, carbon dioxide, and water to create glucose, a simple sugar, which provides energy for growth and development. This ability to synthesize their own food distinguishes them from heterotrophs, which need to consume other organisms for energy.
Q2. What is the process called in which plants convert light energy into chemical energy?
a) Respiration
b) Fermentation
c) Photosynthesis
d) Phototropism
Show Answer
Correct Answer: c) Photosynthesis
Explanation: Photosynthesis is the process by which plants convert light energy into chemical energy. In this process, chlorophyll within the plant cells absorbs sunlight and uses it to convert water and carbon dioxide into oxygen and glucose. This glucose serves as an energy source for the plant, while oxygen is released as a by-product.
Q3. Which gas is taken in by plants during photosynthesis?
a) Oxygen
b) Carbon Dioxide
c) Nitrogen
d) Hydrogen
Show Answer
Correct Answer: b) Carbon Dioxide
Explanation: During photosynthesis, plants take in carbon dioxide (CO2) from the air. This CO2, along with water absorbed by the roots, is used to produce glucose and oxygen. The carbon dioxide enters the plant through small pores in the leaves called stomata, and is then used in the chloroplasts during the photosynthetic process.
Q4. Which part of the plant is primarily involved in the absorption of water from the soil?
a) Leaves
b) Stems
c) Roots
d) Flowers
Show Answer
Correct Answer: c) Roots
Explanation: The roots of a plant are primarily responsible for the absorption of water from the soil. Roots have a large surface area and fine hair-like structures known as root hairs, which increase their efficiency in water uptake. The absorbed water is then transported to the rest of the plant through a system of vessels.
Q5. In addition to sunlight, what are the two main raw materials required for photosynthesis?
a) Oxygen and Carbon Dioxide
b) Nitrogen and Hydrogen
c) Carbon Dioxide and Water
d) Oxygen and Nitrogen
Show Answer
Correct Answer: c) Carbon Dioxide and Water
Explanation: The two main raw materials required for photosynthesis, apart from sunlight, are carbon dioxide (CO2) and water (H2O). Plants absorb carbon dioxide from the air and water from the soil. These substances are then converted into glucose (C6H12O6) and oxygen (O2) through the chemical process of photosynthesis, powered by sunlight.
Q6. What pigment in plants is responsible for absorbing sunlight for photosynthesis?
a) Chlorophyll
b) Carotenoid
c) Anthocyanin
d) Xanthophyll
Show Answer
Correct Answer: a) Chlorophyll
Explanation: Chlorophyll is the pigment responsible for absorbing sunlight in the process of photosynthesis in plants. It gives plants their green color and is primarily found in the chloroplasts of plant cells. Chlorophyll absorbs light most effectively in the blue and red wavelengths, using this energy to convert carbon dioxide and water into glucose and oxygen.
Q7. Which process do plants use to release energy from food?
a) Photosynthesis
b) Cellular respiration
c) Transpiration
d) Phototropism
Show Answer
Correct Answer: b) Cellular respiration
Explanation: Plants use cellular respiration to release energy from food. This process occurs in the mitochondria of plant cells, where glucose produced during photosynthesis is broken down into water, carbon dioxide, and ATP (adenosine triphosphate), the energy currency of the cell. Cellular respiration occurs in all living cells, including both plants and animals.
Q8. What is the main function of stomata in plant leaves?
a) Absorbing sunlight
b) Providing structural support
c) Gas exchange
d) Conducting water
Show Answer
Correct Answer: c) Gas exchange
Explanation: The main function of stomata in plant leaves is gas exchange. Stomata are small openings usually found on the underside of leaves. They allow carbon dioxide to enter the leaf for photosynthesis and oxygen to exit as a byproduct. Stomata can open and close to regulate gas exchange and prevent excessive water loss.
Q9. Which type of plant nutrition involves organisms feeding on dead organic matter?
a) Autotrophic
b) Parasitic
c) Saprotrophic
d) Symbiotic
Show Answer
Correct Answer: c) Saprotrophic
Explanation: Saprotrophic nutrition involves organisms feeding on dead or decaying organic matter. This type of nutrition is common in fungi and certain bacteria, which release enzymes to break down complex organic materials into simpler substances that they can absorb. While not typical of most plants, it’s an important ecological process for recycling nutrients.
Q10. What is the term for the relationship between fungi and plant roots, beneficial to both?
a) Parasitism
b) Commensalism
c) Mutualism
d) Predation
Show Answer
Correct Answer: c) Mutualism
Explanation: The term for the beneficial relationship between fungi and plant roots is mutualism, specifically referred to as mycorrhizal associations. In this relationship, the fungi enhance water and nutrient absorption for the plant, while the plant supplies the fungi with carbohydrates produced through photosynthesis. This symbiotic association is crucial for the health and growth of many plants.