Q30. What is the name of the green leaf pigment that captures sunlight?
[SSC MTS — 2 May 2023, Evening]
(A) Cladophyll
(B) Chlorophyll
(C) Xanthophyll
(D) Cytoplasm
Answer: (B) Chlorophyll
Explanation: Chlorophyll absorbs light that fuels photosynthetic reactions in green plant cells. It is located mainly in chloroplast membranes. Xanthophyll is an accessory yellow pigment, cytoplasm is the cellular matrix, and cladophyll describes a modified stem rather than the green pigment.
Q29. Which conducting tissue carries water and dissolved minerals from roots towards leaves?
[SSC MTS — 3 May 2023, Afternoon]
(A) Xylem
(B) Parenchyma
(C) Collenchyma
(D) Phloem
Answer: (A) Xylem
Explanation: Xylem vessels conduct water and dissolved mineral nutrients upward from roots to stems and leaves. This supplies water for photosynthesis and other metabolic functions. Phloem principally distributes organic food made by photosynthesis, while parenchyma and collenchyma have different major roles.
Q28. What is the ultimate energy source for most living organisms?
[SSC MTS — 11 May 2023, Morning]
(A) Soil
(B) The Sun
(C) Water
(D) Air
Answer: (B) The Sun
Explanation: Sunlight drives photosynthesis in plants, algae and many bacteria. These producers transform solar energy into chemical energy stored in organic food. Food chains pass this energy to consumers, so most ecosystems depend ultimately on the Sun even when individual organisms never receive sunlight.
Q27. When organisms produce their own food from simple inorganic substances, their nutrition is called what?
[SSC MTS — 11 May 2023, Evening]
(A) Heterotrophic
(B) Autotrophic
(C) Saprotrophic
(D) Holozoic
Answer: (B) Autotrophic
Explanation: In autotrophic nutrition, organisms synthesise organic compounds from simple inorganic materials. Green plants normally use light energy for this process. Saprotrophs absorb nutrients from decaying matter, whereas heterotrophs generally rely on food manufactured by other organisms.
Q26. Which water-soluble plant pigments commonly cause red, blue and purple colours in many fruits and leaves?
[SSC CHSL — 10 August 2023, Shift 1]
(A) Coumarins
(B) Anthocyanins
(C) Quercetin alone
(D) Naringenin alone
Answer: (B) Anthocyanins
Explanation: Anthocyanins are flavonoid pigments that commonly give plant tissues red, purple or blue shades. Their visible colour can mask chlorophyll in some leaves. A coloured leaf may therefore remain photosynthetically active even when its green pigment is not obvious.
Q25. Which of these is an insectivorous plant?
[CTET Paper I — 18 January 2023]
(A) Cuscuta
(B) Lichen
(C) Pitcher plant
(D) Cactus
Answer: (C) Pitcher plant
Explanation: Pitcher plants possess modified leaves that trap insects and digest them to obtain scarce mineral nutrients, especially nitrogen. They still carry out photosynthesis to make carbohydrates. Cuscuta is parasitic, lichens represent symbiosis, and cactus is a xerophytic plant.
Q24. Which plants in this list commonly fix atmospheric nitrogen through a legume–bacterium association:
1 Alfalfa,
2 Amaranth,
3 Chickpea,
4 Clover,
5 Purslane,
6 Spinach?
[UPSC CSE Preliminary Examination — 2022]
(A) 1, 3 and 4 only
(B) 1, 3, 5 and 6 only
(C) 2, 4, 5 and 6 only
(D) 1, 2, 4, 5 and 6
Answer: (A) 1, 3 and 4 only
Explanation: Alfalfa, chickpea and clover belong to the legume family and commonly develop root nodules containing nitrogen-fixing bacteria. Amaranth, purslane and spinach are not such legumes. This association converts atmospheric nitrogen into compounds useful for plant nutrition and soil fertility.
Q23. Which statement correctly describes the light-driven events of photosynthesis?
[UPSC CDS-II General Knowledge — 4 September 2022]
(A) Light becomes kinetic energy that oxidises carbon dioxide
(B) Light directly reduces water into sugar
(C) Chlorophyll uses chemical energy to oxidise carbon dioxide
(D) Chlorophyll absorbs light, enabling water splitting and carbon-dioxide reduction
Answer: (D) Chlorophyll absorbs light, enabling water splitting and carbon-dioxide reduction
Explanation: Chlorophyll captures radiant energy during the light-dependent reactions, helping drive the splitting of water. The resulting energy carriers support carbon dioxide reduction and carbohydrate synthesis. Photosynthesis is fundamentally energy storage and carbon fixation, not glucose breakdown or direct conversion into kinetic energy.
Q22. Which statement about plant mineral nutrition is incorrect?
[RRB Group D — 9 September 2022, Shift 2]
(A) Green plants obtain carbon from atmospheric carbon dioxide
(B) Minerals are poorly absorbed by water
(C) Iron and manganese are micronutrients
(D) Roots usually take up water from soil
Answer: (B) Minerals are poorly absorbed by water
Explanation: Roots generally absorb essential mineral nutrients as dissolved ions in soil water, so the claim about poor absorption through water is incorrect. Carbon enters mainly as carbon dioxide, while iron and manganese are required in relatively small amounts as micronutrients.
Q21. Regarding lichens, which combination is correct:
(i) lichens are algae;
(ii) lichens can photosynthesise;
(iii) lichens are fungi alone;
(iv) lichens are symbiotic associations;
(v) lichens are saprotrophs?
[HPSC Haryana Civil Services Preliminary Examination — July 2022]
(A) i and v
(B) ii and iv
(C) i, iii and v
(D) ii, iv and v
Answer: (B) ii and iv
Explanation: Lichens consist of a photosynthetic partner and a fungus living in close association. The photosynthetic partner supplies organic food, while the fungus provides physical support and access to water and minerals. A lichen is not simply an alga or a fungus alone.
