Chemical Coordination in Plants Class-10 Goyal Brothers ICSE Biology Solutions Ch-7

Chemical Coordination in Plants Class-10 Goyal Brothers ICSE Biology Solutions Ch-7.  We Provide Solutions of Test yourself , MCQs, Very Short , Short  Answer Questions of Exercise-7 Chemical Coordination in Plants.  All solutions are given as council prescribe guideline for next upcoming exam. Visit official Website CISCE  for detail information about ICSE Board Class-10 Biology.

Ch-7 Chemical Coordination in Plants Goyal Brothers Prakashan ICSE Class-10 Biology Solutions

Board ICSE
Publications Goyal Brothers publications
Subject  Biology
Class 10th
Writer Dr. K.K. Aggrawal
Chapter-7 Chemical Coordination in Plants
Topics Solutions of MCQ, Very short and Short Answer Questions
Edition for 2022-2023 Academic Session

Note :-  Before Viewing Goyal Brothers Solutions of Chapter-7 Chemical Coordination in Plants. Read the whole chapter carefully with figure.

Test Yourself-1

Ch-7 Chemical Coordination in Plants Goyal Brothers Prakashan ICSE Class-10 Biology Solutions


1. Name the following plant hormones:

(i) These are produced by young shoots, buds, leaves and roots.

(ii) These increases elasticity of stem.

(iii) These promote cytokinesis during cell division.

(iv) It promotes ripening of fruits.

Answer :

(i) Auxins promote stem elongation, inhibit growth of lateral buds (maintains apical dominance). They are produced in the stem, buds, and root tips

(ii) Auxin is a plant hormone produced in the stem tip that promotes cell elongation

(iii) Cytokinins (CK) are a class of plant hormones that promote cell division, or cytokinesis, in plant roots and shoots

(iv) Ethylene is known to be a key player of plant aging, including fruit ripening, and flower and leaf senescence (Abeles et al., 1992)

Test Yourself-2

Ch-7 Chemical Coordination in Plants Goyal Brothers Prakashan ICSE Class-10 Biology Solutions


1. State it the following statements are true (T) or false (F):

(i) The roots of a plant shows negative geotropism.

(ii) The water functions as a stimulus for hydrotropism.

(iii) The shoot of a plant shows negative phototropism.

(iv) The leaves of touch-me-not plant shows chemotropism

Answer :

(i) False 

(ii) True

(iii) False

(iv) True

2. Give one example of each type of plant (organ) showing the following movement.

(i) Negatively geotropism  …..An example of negative geotropism would be the main stem. ‘ ‘For example, the shoot of a plant has negative geotropism, or response to gravity, but the roots have positive geotropism…………

(ii) Positively hydrotropism  …….An example of positive hydrotropism is the growth of plant roots towards higher relative humidity level. The plant is able to sense this at the root cap and then sending signals to the elongating part of the root. Nevertheless, gravitropism often has more influence on root growth than hydrotropism

(iii) Negatively phototropism  ….Negative phototropism is the movement of plant or its part away from sunlight. Such as the growth of roots of a plant deeper inside the ground to absorb nutrients from the soil.

(iv) Chemotropism  ….The growth of a plant part due to chemical stimulus is known as chemotropism or Chemotropism is the movement of a part of the plant in response to a chemical stimulus. The growth of pollen tube towards the ovule induced by a sugary substance as stimulus. This is an example of positive chemotropism

(v) Thigmotropism  ….An example of thigmotropism is the coiling movement of tendrils in the direction of an object that it touches. On the other hand, the folding movement of the Mimosa pudica leaflets, can be considered as an example of thigmonastism


Ch-7 Chemical Coordination in Plants Goyal Brothers Prakashan ICSE Class-10 Biology Solutions


Choose the most Appropriate Answer

1. The internal factor of a plant is

(a) light

(b) growth regulator

(c) moisture

(d) oxygen

Answer : (b) growth regulator

2. Auxins are produced by

(a) old leaves

(b) fruits

(c) buds

(d) wood

Answer : (c) buds

3. Which of the following is used in agriculture for ripening banana and mango?

(a) Ethyphon

(b) ABA

(c) Gibberellin

(d) Cytokinin

Answer : (a) Ethyphon (Ethylene)

4. Which of the following acts as a stimulus for geotropism?

(a) Light

(b) Water

(c) Contact

(d) Gravity

Answer : (d) Gravity

5. The growing leaves show

(a) geotropism

(b) hydrotropism

(c) phototropism

(d) thigmotropism

Answer : (c) phototropism


Ch-7 Chemical Coordination in Plants Goyal Brothers Prakashan ICSE Class-10 Biology Solutions


Question 1. Complete the given statements:

(i) The shoot of a plant bends towards the source of …………..

(ii) When a seed germinates the root grows towards the …………..

(iii) The tendrils of pea plant grow round the surface of …………..

(iv) IAA, IBA, NAA and 2, 4-D are …………..

(v) GA, GA2, GA3 and so on are ……………

Answer :

(i) light

(ii) Gravity

(iii) wrap around or to hook a support.

(iv) synthetic auxins

(v) Gibberellins

Question 2. Match the following:

Column A Column B
(i) Touch (a) Phototropism
(ii) Moisture (b) Chemotropism
(iii) Sunlight (c) Thigmotropism
(iv) Gravitational force (d) Hydrotropism
(v) Sugar (e) Geotropism

Answer :

Column A Column B
(i) Touch (c) Thigmotropism
(ii) Moisture (d) Hydrotropism
(iii) Sunlight (a) Phototropism
(iv) Gravitational force (e) Geotropism
(v) Sugar (b) Chemotropism


Ch-7 Chemical Coordination in Plants Goyal Brothers Prakashan ICSE Class-10 Biology Solutions


Question 1. Define the following :

(i) Tropism

(ii) Hydrotropism

(iii) Stress hormone

(iv) Thigmotropism

Answer :

(i) response or orientation of a plant or certain lower animals to a stimulus that acts with greater intensity from one direction than another. It may be achieved by active movement or by structural alteration.

(ii) a tropism (as in plant roots) in which water or water vapor is the orienting factor

(iii) Cortisol is a naturally-occurring steroid hormone that plays a key role in the body’s stress response. 1 While it is often called “the stress hormone” for its best-known role, it also contributes to many of the body’s processes

(iv)  a tropism in which physical contact especially with a solid or a rigid surface is the factor causing orientation of the whole organism

Question 2. Write briefly about the following:

(i) Cell elongation due to auxins

(ii) Phototropism

(iii) Effects of ethylene hormone on plants

(iv) Physiological effects of gibberelins.

Answer :

(i) Auxin is a plant hormone produced in the stem tip that promotes cell elongation. Auxin moves to the darker side of the plant, causing the cells there to grow larger than corresponding cells on the lighter side of the plant.

(ii) Phototropism is the growth of an organism in response to a light stimulus. Phototropism is most often observed in plants, but can also occur in other organisms such as fungi. The cells on the plant that are farthest from the light contain a hormone called auxin that reacts when phototropism occurs.

(iii) The ethylene in a plant growth regulator that acts as a trace level of entire plant life by regulating and stimulating the opening of flowers, fruit ripening and shedding of leaves. During the ancient days, Egyptians used this technique with gash figs to stimulate ripening

(iv) Some of the major physiological effects of gibberellins are as follows: Gibberellins are weakly acidic growth hormones having gibbane ring structure which cause cell elongation of intact plants in general and increased internodal length of genetically dwarfed plants

— : End of Chemical Coordination in Plants  Class-10 Goyal Brothers Solutions :–

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