Railway Science (Biology-Nutrition in Plant)

Total Questions: 50

31. During photosynthesis six water molecules are produced from: [RRC Group D 20/09/2022 (Evening)]

Correct Answer: (d) 12𝐻₂𝑂
Solution:

Photosynthesis - Process of converting light energy into chemical energy. The basic reaction: COβ‚‚ + 2Hβ‚‚O β†’ (CHβ‚‚O) + Oβ‚‚ + Hβ‚‚O. To produce glucose (C₆H₁₂O₆), 12 water molecules and 6 of carbon dioxide are needed. 6COβ‚‚ + 12Hβ‚‚O + Light Energy β†’ C₆H₁₂O₆ + 6Oβ‚‚Β + 6Hβ‚‚O.

32. Some characteristic features of autotrophs are listed below. Which of the given statements is INCORRECT with respect to autotrophs? [RRC Group D 20/09/2022 (Evening)]

Correct Answer: (d) The carbohydrates not used immediately are stored in the form of glycogen.
Solution:

Plants are the only organisms that can prepare food for themselves by using water, carbon dioxide and sunlight.

33. In the following diagrams, the blue arrows represent transport through the xylem vessels and the red arrows represent transport through the phloem vessels. Which diagram shows the correct direction of transport in the plant stem? [RRC Group D 26/09/2022 (Morning)]

Correct Answer: (b) Diagram B
Solution:

Plants have two transport systems - Xylem and Phloem (Vascular tissues). Xylem - The water is absorbed by the root hair and undergoes cell to cell movement by osmosis until it reaches the xylem.
This water is then transported through the xylem vessels to the leaves. It has unidirectional flow always in upward direction.
Phloem - It is responsible for translocation of nutrients and sugar like carbohydrates, produced by the leaves, flow of these nutrients are bidirectional.

34. In plants during the spring season, nutrients stored in the roots usually move to the ______. [RRC Group D 26/09/2022 (Afternoon)]

Correct Answer: (b) Bud
Solution:

Food is synthesized in the green parts of a plant. The non-green parts are dependent on the photosynthetic cells for nourishment. The food in the form of sucrose is transported by the vascular tissue phloem.
In Early Spring when the leaves are shed, the sugar stored in roots mobilizes the organic material towards the growing Buds. so, the direction of the source and sink is reversed which means bidirectional flow of food occurs in the phloem.

35. Plant root cells also need oxygen to generate energy. So roots take up air from : [RRC Group D 26/09/2022 (Evening)]

Correct Answer: (a) air spaces between soil particles
Solution:

The air in the soil particles comes into touch with the root hairs. The oxygen in soil particles diffuses into root hair and reaches all of the root’s cells, used in respiration. Diffusion allows carbon dioxide formed in the root’s cells during breathing to escape through the same root hair. Cytoplasm : The gelatinous liquid that fills the inside of a cell. Stomata : The tiny openings present on the epidermis of leaves.

36. Where can we find such cells with thickened cell walls in a plant? [RRC Group D 29/09/2022 (Evening)]

Correct Answer: (a) In phloem
Solution:

Phloem is the specialised food conducting tissue of the plant cell, which assist the conductance of food (carbohydrates and amino acids) from the photosynthesized part (leaf) to the non-photosynthesized parts (like stem, flowers, buds, fruits, roots).

37. Which among the following statement is FALSE about transportation through phloem? [RRC Group D 30/09/2022 (Morning)]

Correct Answer: (a) Transportation in phloem uses GTP & CTP
Solution:

GTP (Guanosine triphosphate) is used as an energy source for the binding of a new amino-bound tRNA to the A site of the ribosome and as an energy source for the translocation of the ribosome towards the 3' end of the mRNA.
CTP (Cytidine triphosphate) is a coenzyme in metabolic reactions like the synthesis of glycerophospholipids, where it is used for activation and transfer of diacylglycerol and lipid head groups and glycosylation of proteins.

38. Which of the following pathways correctly shows the transportation of water from soil to leaves? [RRC Group D 30/09/2022 (Evening)]

Correct Answer: (d) Soil → root hairs→ root cortex → xylem of roots → xylem of stem → xylem of leaf
Solution:

Transportation in Plants: Two types of "transport" tissues in plantsxylem (water and minerals) and phloem (food) . Root hair absorbs water and minerals from the soil through diffusion.
The xylem (transport water and mineral) is made up of small vessels that connect the roots and leaves. The phloem tissue is the main pathway for the long-distance transport of assimilates from source to sink organs in plants

39. Which of the following processes does not occur during photosynthesis? [RRC Group D 06/10/2022 (Morning)]

Correct Answer: (d) Absorption of oxygen
Solution:

Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar.
Reaction - 6COβ‚‚ (Carbon dioxide) + 6Hβ‚‚O (Water) β†’ C₆H₁₂O₆ (Glucose) + 6Oβ‚‚Β (Oxygen). Carbon dioxide is reduced to carbohydrates.

40. What makes the xylem vessels waterproof? [RRC Group D 07/10/2022 (Evening)]

Correct Answer: (c) Lignin
Solution:

Cellulose - determines the shape of the plant and allows the plant to grow upright. Cell wall of plants and their organs such as fruits, leaves, and vegetables contain cellulose.
Cutin - waxy and water repellent substance present in cuticles of plants. Important role in waterproofing the leaves and fruits of higher plants. Suberin is a wax-like fatty substance, occurring in cork cell walls - Main function to prevent water from penetrating the tissue.