Q1. What pigment is necessary for the process of photosynthesis in plants?
a) Xanthophyll
b) Chlorophyll
c) Anthocyanin
d) Carotene
Answer: b) Chlorophyll
Explanation: Chlorophyll is the green pigment located in the chloroplasts of plant cells that captures the energy of sunlight for photosynthesis, making it essential for this process.
Q2. Which of the following organisms is an example of a heterotroph?
a) Cuscuta
b) Algae
c) Grass
d) Wheat
Answer: a) Cuscuta
Explanation: Cuscuta (Amarbel) is a parasitic plant that does not have chlorophyll and relies on other plants for its nutrition, making it a heterotroph.
Q3. During photosynthesis, plants take in which gas from the atmosphere?
a) Oxygen
b) Nitrogen
c) Carbon dioxide
d) Hydrogen
Answer: c) Carbon dioxide
Explanation: Plants absorb carbon dioxide from the atmosphere through stomata during photosynthesis to synthesize carbohydrates.
Q4. What is the role of Rhizobium bacteria in plants?
a) Decomposing dead organic matter
b) Fixing atmospheric nitrogen into a usable form
c) Causing diseases in plants
d) Absorbing minerals from the soil
Answer: b) Fixing atmospheric nitrogen into a usable form
Explanation: Rhizobium bacteria live symbiotically in the roots of leguminous plants, converting atmospheric nitrogen into a form that plants can use for growth.
Q5. Which of the following is not a product of photosynthesis?
a) Glucose
b) Oxygen
c) Carbon dioxide
d) Water
Answer: c) Carbon dioxide
Explanation: Photosynthesis produces glucose and oxygen as end products, utilizing carbon dioxide and water as raw materials.
Q6. How do saprotrophs obtain their nutrients?
a) By performing photosynthesis
b) From the host they parasitize
c) By absorbing nutrients from dead and decaying matter
d) By capturing and digesting insects
Answer: c) By absorbing nutrients from dead and decaying matter
Explanation: Saprotrophs, like fungi, obtain their nutrients by absorbing them from dead and decaying organic matter, utilizing a saprotrophic mode of nutrition.
Q7. Which process is used by plants to convert carbon dioxide and water into glucose and oxygen, using sunlight?
a) Cellular respiration
b) Fermentation
c) Photosynthesis
d) Digestion
Answer: c) Photosynthesis
Explanation: Photosynthesis is the process by which plants use sunlight to synthesize nutrients (glucose) from carbon dioxide and water, releasing oxygen in the process.
Q8. What is the primary function of stomata located on the surface of plant leaves?
a) Absorption of water
b) Transport of nutrients
c) Exchange of gases
d) Storage of chlorophyll
Answer: c) Exchange of gases
Explanation: Stomata are tiny openings on the leaf surface that allow for the exchange of gases (carbon dioxide in, oxygen out) necessary for photosynthesis and respiration.
Q9. Plants like Cuscuta that do not have chlorophyll and depend on other plants for their nutrition are classified as:
a) Autotrophs
b) Heterotrophs
c) Saprotrophs
d) Phototrophs
Answer: b) Heterotrophs
Explanation: Cuscuta and similar plants are heterotrophs because they cannot synthesize their own food due to the lack of chlorophyll and depend on other plants for their nutrition.
Q10. Which element is fixed in the soil by Rhizobium bacteria, making it available to plants?
a) Potassium
b) Nitrogen
c) Phosphorus
d) Magnesium
Answer: b) Nitrogen
Explanation: Rhizobium bacteria fix atmospheric nitrogen into a soluble form that plants can absorb and use, enriching the soil with nitrogen that is essential for plant growth.
Q11. The process of photosynthesis mainly takes place in which part of the plant?
a) Roots
b) Stems
c) Leaves
d) Flowers
Answer: c) Leaves
Explanation: Leaves are the primary site of photosynthesis in plants, as they contain chlorophyll, the green pigment that captures sunlight to synthesize food.
Q12. What mode of nutrition is found in fungi?
a) Autotrophic nutrition
b) Heterotrophic nutrition
c) Insectivorous nutrition
d) Parasitic nutrition
Answer: b) Heterotrophic nutrition
Explanation: Fungi use heterotrophic nutrition, specifically saprotrophic nutrition, where they absorb nutrients from dead and decaying matter.
Q13. Which of the following is true about insectivorous plants?
a) They do not perform photosynthesis.
b) They trap insects because they lack chlorophyll.
c) They obtain some nutrients by trapping and digesting insects.
d) They are considered heterotrophs.
Answer: c) They obtain some nutrients by trapping and digesting insects.
Explanation: Insectivorous plants, such as the pitcher plant, are capable of photosynthesis but trap insects to obtain additional nutrients, like nitrogen, which might be scarce in their soil environment.
Q14. The symbiotic relationship between leguminous plants and Rhizobium bacteria is beneficial because:
a) It enhances soil fertility by increasing its nitrogen content.
b) It helps in the synthesis of chlorophyll.
c) It protects the plant from herbivores.
d) It increases the water absorption capacity of the plant.
Answer: a) It enhances soil fertility by increasing its nitrogen content.
Explanation: The symbiotic relationship between leguminous plants and Rhizobium bacteria allows the bacteria to fix atmospheric nitrogen into a form that the plant can use, thus enriching the soil’s nitrogen content.
Q15. Where do plants get the carbon dioxide required for photosynthesis?
a) From the soil
b) From water
c) Directly from the atmosphere
d) From decomposed organic matter
Answer: c) Directly from the atmosphere
Explanation: Plants absorb carbon dioxide directly from the atmosphere through the stomata present on their leaves.
Q16. Why are fertilizers added to the soil?
a) To add more water to the soil
b) To increase the soil’s ability to hold oxygen
c) To replenish the soil with nutrients required for plant growth
d) To decrease the soil’s pH value
Answer: c) To replenish the soil with nutrients required for plant growth
Explanation: Fertilizers are added to the soil to replenish it with essential nutrients like nitrogen, phosphorus, and potassium, which are depleted after successive plantings.
Q17. Which of the following is an example of an autotroph?
a) Mushroom
b) Human
c) Algae
d) Lion
Answer: c) Algae
Explanation: Algae are autotrophs because they contain chlorophyll and can synthesize their own food through the process of photosynthesis.
Q18. What is the function of chlorophyll in photosynthesis?
a) It helps in the absorption of water from the soil.
b) It captures the energy of sunlight.
c) It aids in the transport of nutrients from the soil.
d) It releases oxygen into the atmosphere.
Answer: b) It captures the energy of sunlight.
Explanation: Chlorophyll is a pigment that captures the energy of sunlight, which is then used to convert carbon dioxide and water into glucose and oxygen during photosynthesis.
Q19. What is the main advantage of the symbiotic relationship between Rhizobium bacteria and leguminous plants?
a) It increases the plant’s resistance to diseases.
b) It allows the bacteria to perform photosynthesis.
c) It enables plants to utilize atmospheric nitrogen.
d) It helps in faster decomposition of organic matter.
Answer: c) It enables plants to utilize atmospheric nitrogen.
Explanation: The symbiotic relationship between Rhizobium bacteria and leguminous plants allows the bacteria to fix atmospheric nitrogen into a form that the plant can use, aiding in plant nutrition.
Q20. In which of the following environments would you expect to find saprotrophic nutrition?
a) A sunlit field of wheat
b) On a piece of bread kept in moist conditions
c) In the roots of a leguminous plant
d) Within the leaves of a green plant
Answer: b) On a piece of bread kept in moist conditions
Explanation: Saprotrophic nutrition is observed in organisms like fungi, which absorb nutrients from dead and decaying matter, such as a piece of bread kept in moist conditions.
Q21. What is the role of guard cells in plants?
a) To absorb water from the soil
b) To capture sunlight
c) To regulate the opening and closing of stomata
d) To fix atmospheric nitrogen
Answer: c) To regulate the opening and closing of stomata
Explanation: Guard cells are specialized cells in the epidermis of leaves, stems, and other organs that are used to regulate the opening and closing of stomata to facilitate gas exchange and control water loss.
Q22. Which of the following is not a component of the process of photosynthesis?
a) Sunlight
b) Oxygen
c) Carbon dioxide
d) Water
Answer: b) Oxygen
Explanation: Oxygen is a product, not a component, of the photosynthesis process. The components required for photosynthesis include sunlight, carbon dioxide, and water.
Q23. What kind of relationship do fungi form with the roots of plants in a mycorrhizal association?
a) Parasitic
b) Predatory
c) Symbiotic
d) Saprotrophic
Answer: c) Symbiotic
Explanation: In a mycorrhizal association, fungi form a symbiotic relationship with the roots of plants, where both organisms benefit: the plant receives enhanced nutrient and water absorption, while the fungus gains carbohydrates produced by the plant.
Q24. Which term describes the type of nutrition in which organisms prepare their own food from simple substances?
a) Heterotrophic nutrition
b) Autotrophic nutrition
c) Saprotrophic nutrition
d) Parasitic nutrition
Answer: b) Autotrophic nutrition
Explanation: Autotrophic nutrition refers to the mode of nutrition in which organisms make their own food from simple substances like carbon dioxide and water, using sunlight (in the case of photosynthesis).
Q25. What substance do insectivorous plants, such as the pitcher plant, secrete to digest trapped insects?
a) Chlorophyll
b) Nitrogen
c) Digestive enzymes
d) Carbon dioxide
Answer: c) Digestive enzymes
Explanation: Insectivorous plants like the pitcher plant secrete digestive enzymes into their specialized structures to break down trapped insects, allowing them to absorb the nutrients.
Q26. The green color of leaves is due to the presence of:
a) Xylem
b) Phloem
c) Chlorophyll
d) Rhizobium
Answer: c) Chlorophyll
Explanation: Chlorophyll is the green pigment found in the chloroplasts of plant cells, responsible for the absorption of light to provide energy for photosynthesis, giving leaves their green color.
Q27. Which of the following is a characteristic feature of saprotrophs?
a) They live in symbiotic relationships with other organisms.
b) They synthesize their own food through photosynthesis.
c) They feed on dead and decaying organic matter.
d) They capture insects for nutrition.
Answer: c) They feed on dead and decaying organic matter.
Explanation: Saprotrophs, such as fungi, feed on dead and decaying organic matter by secreting enzymes that break down the matter outside their body and then absorbing the nutrients.
Q28. The pores present on the surface of leaves, which facilitate gas exchange, are called:
a) Xylem
b) Phloem
c) Stomata
d) Chloroplasts
Answer: c) Stomata
Explanation: Stomata are tiny openings or pores present on the leaf surface that facilitate the exchange of gases (carbon dioxide in, oxygen out) necessary for photosynthesis.
Q29. Which of the following plants is known to have a parasitic mode of nutrition?
a) Wheat
b) Cuscuta
c) Sunflower
d) Algae
Answer: b) Cuscuta
Explanation: Cuscuta, also known as dodder or Amarbel, is a parasitic plant that lacks chlorophyll and derives its nutrition from other living plants, making it dependent on its host for survival.
Q30. Nitrogen fixation in the soil is primarily carried out by:
a) Algae
b) Rhizobium bacteria
c) Saprotrophic fungi
d) Insectivorous plants
Answer: b) Rhizobium bacteria
Explanation: Rhizobium bacteria, found in the root nodules of leguminous plants, are primarily responsible for fixing atmospheric nitrogen into a form that plants can use, enriching the soil with nitrogen.
Q31. What is photosynthesis?
a) The process by which plants release carbon dioxide.
b) The process by which plants consume oxygen.
c) The process by which plants convert carbon dioxide and water into glucose and oxygen using sunlight.
d) The process by which plants absorb nutrients from the soil.
Answer: c) The process by which plants convert carbon dioxide and water into glucose and oxygen using sunlight.
Explanation: Photosynthesis is the process where plants use sunlight to convert carbon dioxide and water into glucose, a type of sugar that serves as their food, and oxygen as a byproduct.
Q32. Which organisms are known as autotrophs?
a) Animals that consume other organisms
b) Plants that prepare their own food
c) Fungi that decompose organic matter
d) Parasites that feed on host organisms
Answer: b) Plants that prepare their own food
Explanation: Autotrophs are organisms that can produce their own food from inorganic substances. Plants are the most common examples because they can make their own food through photosynthesis.
Q33. How do plants absorb minerals from the soil?
a) Through the stomata
b) Through the chlorophyll
c) Through the roots
d) Through the leaves
Answer: c) Through the roots
Explanation: Plants absorb water and minerals from the soil through their roots. The roots have tiny hair-like structures that increase the surface area for absorption.
Q34. What is the significance of chlorophyll in plants?
a) It helps plants in absorbing water.
b) It gives plants the ability to undergo photosynthesis by trapping sunlight.
c) It protects plants from pests and diseases.
d) It aids in the transport of nutrients from the soil.
Answer: b) It gives plants the ability to undergo photosynthesis by trapping sunlight.
Explanation: Chlorophyll is a green pigment found in the chloroplasts of plants that enables them to capture the energy from sunlight necessary for photosynthesis.
Q35. Which of the following is not a byproduct of photosynthesis?
a) Glucose
b) Oxygen
c) Carbon dioxide
d) Water
Answer: c) Carbon dioxide
Explanation: Carbon dioxide is a raw material used in photosynthesis, not a byproduct. The byproducts of photosynthesis are glucose, which is used by the plant for energy, and oxygen, which is released into the atmosphere.
Q36. What is a parasite in the context of plant nutrition?
a) A plant that provides nutrients to other plants
b) A plant that decomposes dead organic matter
c) A plant that derives nutrients from living host plants
d) A plant that fixes atmospheric nitrogen
Answer: c) A plant that derives nutrients from living host plants
Explanation: A parasitic plant depends on a host plant for nutrients. It attaches to the host plant and extracts water and nutrients directly, often harming the host in the process.