Chemical Coordination in Plants assertion reason questions for Class 10 ICSE
1.) Assertion (A): Auxins promote the elongation of plant cells.
Reason (R): Auxins stimulate cell division in the shoot apical meristem.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
2.) Assertion (A): Gibberellins are involved in seed germination.
Reason (R): Gibberellins break seed dormancy and promote the synthesis of amylase.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (c) A is True and R is False
3.) Assertion (A): Abscisic acid (ABA) promotes stomatal closure.
Reason (R): ABA inhibits the uptake of potassium ions by guard cells.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
- ) Assertion (A): Ethylene is a plant hormone involved in fruit ripening.
Reason (R): Ethylene stimulates the conversion of starch to sugars in fruits.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
5.) Assertion (A): Cytokinins promote cell division.
Reason (R): Cytokinins stimulate the activity of the cell cycle-promoting enzymes.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
6.) Assertion (A): Phototropism is influenced by auxins.
Reason (R): Auxins move to the shaded side of the shoot, promoting cell elongation.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
- ) Assertion (A): Abscisic acid (ABA) is involved in drought stress response.
Reason (R): ABA induces the closure of stomata to reduce water loss.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
8.) Assertion (A): Gibberellins promote stem elongation.
Reason (R): Gibberellins stimulate cell division and expansion in the internodes.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
9.) Assertion (A): Ethylene is involved in the abscission of leaves and fruits.
Reason (R): Ethylene promotes the breakdown of cell walls in the abscission zone.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
10.) Assertion (A): Gibberellins are used in agriculture to promote flowering.
Reason (R): Gibberellins induce the formation of flower buds.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
11.) Assertion (A): Auxins inhibit the growth of lateral buds.
Reason (R): Auxins suppress the activity of lateral buds by promoting apical dominance.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
12.) Assertion (A): Ethylene acts as a senescence-promoting hormone.
Reason (R): Ethylene enhances the breakdown of chlorophyll in aging leaves.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
13.) Assertion (A): Cytokinins delay the senescence of leaves.
Reason (R): Cytokinins inhibit the breakdown of chlorophyll in aging leaves.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
14.) Assertion (A): Phototropism is a growth response toward light.
Reason (R): Auxins move away from the illuminated side of the shoot, causing cell elongation on the shaded side.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
15.) Assertion (A): Abscisic acid (ABA) is involved in seed dormancy.
Reason (R): ABA inhibits the germination of seeds by blocking the action of gibberellins.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
16.) Assertion (A): Gibberellins stimulate the mobilization of stored nutrients in seeds.
Reason (R): Gibberellins promote the synthesis of enzymes that break down starch into sugars.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
17.) Assertion (A): Ethylene induces the ripening of fruits.
Reason (R): Ethylene activates genes that promote the production of enzymes involved in fruit ripening.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
18.) Assertion (A): Cytokinins play a role in the formation of lateral roots.
Reason (R): Cytokinins stimulate
cell division in the root meristem.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
19.) Assertion (A): Abscisic acid (ABA) is involved in the closing of stomata.
Reason (R): ABA induces the efflux of potassium ions from guard cells, leading to water loss and stomatal closure.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
20.) Assertion (A): Gibberellins promote flowering in long-day plants.
Reason (R): Gibberellins induce the synthesis of floral meristem-inducing
proteins.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (c) A is True and R is False
21.) Assertion (A): Auxins are involved in the initiation of root development.
Reason (R): Auxins stimulate cell division and elongation in the root meristem.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
22.) Assertion (A): Ethylene is a gaseous plant hormone.
Reason (R): Ethylene can diffuse through the air and affect nearby plants.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
23.) Assertion (A): Cytokinins inhibit leaf senescence.
Reason (R): Cytokinins delay the breakdown of chlorophyll in aging leaves.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
24.) Assertion (A): Phototropism is more pronounced in dicot stems than in monocot stems.
Reason (R): Dicot stems exhibit greater flexibility in response to light direction changes.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (c) A is True and R is False
25.) Assertion (A): Gibberellins stimulate the elongation of internodes.
Reason (R): Gibberellins promote cell division and expansion in the internodes.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
26.) Assertion (A): Abscisic acid (ABA) is involved in seed maturation.
Reason (R): ABA promotes the synthesis of storage proteins and lipids in seeds.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
27.) Assertion (A): Ethylene inhibits stem elongation.
Reason (R): Ethylene promotes the synthesis of proteins that inhibit cell elongation.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
28.) Assertion (A): Cytokinins are synthesized in the root apical meristem.
Reason (R): Cytokinins stimulate cell division in the root meristem.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
29.) Assertion (A): Auxins move basipetally in the phloem.
Reason (R): Auxins are transported from the shoot apical meristem to the root tips.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (d) A is False and R is True
30.) Assertion (A): Gibberellins are involved in the mobilization of nutrients from senescing leaves to developing seeds.
Reason (R): Gibberellins stimulate the synthesis of enzymes that break down proteins and transport nutrients.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (b) Both A and R are False
31.) Assertion (A): Gibberellins promote the elongation of stems.
Reason (R): Gibberellins stimulate cell division and expansion in the internodes.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
32.) Assertion (A): Abscisic acid (ABA) promotes seed germination.
Reason (R): ABA breaks seed dormancy by stimulating the synthesis of gibberellins.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (b) Both A and R are False
33.) Assertion (A): Cytokinins are involved in the initiation of lateral bud growth.
Reason (R): Cytokinins stimulate cell division in the axillary buds.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
34.) Assertion (A): Phototropism is influenced by the distribution of auxins in the shoot.
Reason (R): Auxins move toward the illuminated side of the shoot, causing cell elongation on the shaded side.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True
35.) Assertion (A): Ethylene promotes the abscission of leaves and fruits.
Reason (R): Ethylene activates genes that lead to the breakdown of cell walls in the abscission zone.
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True
Answer: (a) Both A and R are True