CBSE Solutions for Class 10 Biology

CBSE Solutions for class 10 Subject & Chapters Wise :

The plant hormone called ………… is involved in inhibiting growth and cause wilting of leaves.

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Abscisic acid

Movement of roots away from light is an example of ………… phototropism.

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negative

Directional movement in seedling is a ………… dependent movement.

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growth

The information is acquired by the tip of the ………… of a nerve cell which sets off ………… impulse in it.

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dendrite, electrical

Chemicals released from the nerve endings of one neuron travel through a gap called …………. to reach the next neuron.

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Synapse

The fundamental unit of the tissues for conducting information via electrical impulses from one part of the body to another are called ………… or …………

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nerve cells, neurons

The ………… are the quick responses produced involuntarily in human beings to protect them from the situation which may be dangerous to them e.g., touching a hot object.

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reflex actions

The centre associated with hunger which gives a sensation of feeling full is present in the ………… part of the human brain.

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fore brain

 

 

The spinal cord is protected by the ………… or the backbone.

 
 
 
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vertebral column

The nervous system uses ……… impulses to transmit messages.

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electrical

Control and coordination are the functions of the nervous system and ……… in our body.

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hormones

Central nervous system consists of ……… and ……… .

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brain, spinal cord

Largest part of the brain is ……… .

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cerebrum

Defeciency of ……… hormone in childhood leads to dwarfism in humans.

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growth

The growth of pollen tubes towards the ovules is the result of a ……… movement.

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chemotropic

List the similarities and differences between aerobic and anaerobic respiration.

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Answer :

Similarity:
(i) In both aerobic and anaerobic respiration, food is broken down to release energy.
(ii) Both takes place inside cells.
(iii) Both produces byproducts.

Differences:

Aerobic Respiration

Anaerobic Respiration

(i) It takes place in the presence of oxygen.

(i) It takes place in the absence of oxygen.

(ii) Energy is released in higher amount.

(ii) Energy is released in lesser amount.

(iii) Carbon dioxide and water are produced as byproducts.

(iii) Carbon dioxide and water are produced as byproducts.

(iv) It is a slow process.

(iv) It is a fast process.

(v) Examples: Animals and plants cells.

(iv) Examples: Human cells, yeast, Bacteria etc.

How are involuntary actions and reflex actions different from each other?

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Answer :

All reflex actions are involuntary in nature but all involutary actions are not reflexes as the beating of heart is an involuntary action but is not reflex action.

Reflex actions are very quick but all involutary actions may not be very fast as in heart beating.
A reflex action may involve any muscle or a gland as we withdraw our hand on touching a hot object but all involuntary actions involve only smooth i.e., involuntary or cardiac muscles.

Reflex actions are at the level of spinal cord whereas the involuntary actions generally involve brain too.
Nerves and autonomious nervous system can increase or decrease the rate of involuntary actions but reflex actions can be controlled by great will only and are not usually controllable.

Reflex actions are done to meet emergencies where as an inv.action may or may not be for just meeting an emergency but may be a critical lie process as circulation of blood, swallowing of food, movement of food in food pipe, etc.

What is the need for a system of control and coordination in an organism?

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Co-ordination in this sense refers to the regulation or control of body activity.
Plants need very little in the way of a control system. Since growth and reproduction are about the only things that are regulated, a rapid control system is not required and hormonal control is all they possess.

Animals are continually moving through new environments that may pose all types of changes and threatening situations to the organism. This requires the rapid and precise control of a nervous system. Hormones regulate slower activities, such as growth, development and reproduction.

How does chemical coordination occur in plants?

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Answer :

It has been found that the growth of plants is regulated by certain chemical substances which are synthesized by the plants in very small amounts. These are known as plant hormones or phytohormones.

They are the organic substances which either promote or inhibit growth. A phytohormones can be defined as a chemical substances which are produced naturally in plants and are capable of translocation and regulating one or more physiological processes when present in low concentration. Main categories of plant hormones are:

  1. Auxins
  2. Gibberellins
  3. Cytokinins
  4. Ethylene
  5. Abscisic acid

Auxins and Gibberellins stimulate cell elongations, cytokinins stimulate cell division ethylene promotes transverse or isodiametric growth and abscisic acid is a growth inhibitor.

How is the movement of leaves of the sensitive plant different from the movement of a shoot towards light ?

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Answer :

Movement of leaves of sensitive plant

Movement of a shoot towards light

1. It is a nastic movement which does not depend on the direction of stimulus applied.

1. It is a tropic movement which depends on the direction of stimulus applied.

2. The stimulus is touch.

2. The stimulus is light.

3. It is caused by the sudden loss of water from the swellings at the base of leaves.

3. It is caused by the unequal growth on the two sides of the shoot.

4. It is not a growth movement.

4. It is a growth movement.

How does chemical coordination take place in animals ?

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Answer :

Chemical coordination in animals takes place through the hormones secreted by the endocrine glands. Coordination in animals takes place through hormone system as well as nervous system which is called endocrine system. Endocrine glands secrete animal hormones directly into the blood that reach to the specific cells. Special type of molecules are present on the surface of cells to detect these hormones. These cells act according to the information that a particular hormone carries.

What is the function of receptors in our body ? Think of situations where receptors do not work properly. What problems are likely to arise ? [AICBSE 2016]

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Answer :

Receptors are specialised cells located in our sense organs like ear, nose, skin, tongue and eyes. The function of receptors is to detect information from the environment. For example, olfactory receptors detect smell. If receptors do not work properly, the information obtained from the environment will be delayed to reach the spinal cord or brain. In this situation, the response to the environmental stimulus will be delayed causing harm to the body. For example, if skin receptors are damaged, and one accidentally touches a hot object, then his/her hands might get burn as the damaged receptor cannot perceive the external stimuli of heat and pain

How are involuntary actions and reflex actions different from each other ?

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Answer :

 

Involuntary actions

Reflex actions

 1. Those actions which occur immediately without any thinking are called involuntary actions.

1. Reflex action is an immediate response to an event which does not require any processing by brain.

2. Involuntary actions are controlled by mid and hind brain.
Example: Breathing, beating of heart, etc.

2. Reflex actions are controlled by spinal cord.
Example: Sneezing, coughing, etc.

Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.

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Answer :

Nervous mechanism

Hormonal mechanism

It is a fast process.

It is a slow process.

Arteries and glands are affected.

It affects the target organ.

It transmits in electrochemical form.

It transmits in chemical form.

It does not control metabolism.

It controls metabolism.

Growth is not affected.

Growth is affected.

What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs ?

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Answer :

Movement in a sensitive (mimosa) plant

Movement in legs of a human

1. The leaves of a sensitive plant like mimosa are sensitive to touch.

1. Leg is in control of nerve muscles.

2. It is not controlled by any part of the plant.

2. It is controlled by brain and spinal cord.

3. In this, cells change their shape on changing the amount of water in them.

3. Amount of water has no effect on the movement of muscles.

changing the amount of water in them.

the movement of muscles.

4. The movement in a sensitive plant are nastic movement.

4. The movement in our leg is due to voluntary nervous system.

(a)

  1. Name the parts labelled A and B in the neuron drawn above.
  2. Which part acquires the information in the neuron ?
    NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination HOTS Q7
  3. Through which part does the information travel ?
  4. In what form does this information travel ?
  5. Where is the impulse converted into a chemical signal for onward transmission ?

(b) Name the hormone secreted by thyroid. What is the function ?
(c) Why is the use of iodised salt advisable ?
(CBSE A.I. 2008 Compt.)

 

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Answer :

(a)

  1. A-Dendrite, B-Axon
  2. Dandrite.
  3. Dandrite to cell body or cyton to axon.
  4. Electrical impulse
  5. In the region of synapse.

Impulse stimulates the release of chemical neurotransmitter from the surface of presynaptic knob or bouton of axon terminal. Neurotransmitter (e.g. acetylcholine) comes in contact with chemoreceptor sites of post-synaptic membrane of the next neuron and generates a fresh impulse.

(b) Thyroxine:
Function of Thyroxine. It controls

  1. Basal metabolic rate
  2. Metabalism of carbohydrates, fats and proteins
  3. Consumption of energy in physical activity and body temperature
  4. Development and differentiation.

(c) Iodised Salt: Salt is iodised to provide iodine to thyroid for synthesis of thyroxine which is iodine containing hormone.

(a) What are plant hormones ? Give one example each of a plant hormone that

  1. promotes growth
  2. inhibits growth.
  3. promotes cell division
  4. promotes the growth of a tendril around a support. (CCE 2011)

(b) Name the parts labelled A, B and C in the diagram given below. Write one function of each part. (CBSE A.I. 2008 Comptt. Delhi 2008 Comptt.)

NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination HOTS Q8

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Answer :



Answer:
(a) Plant Hormones:
Phytohormones are chemical substances other than nutrients produced naturally in plants which regulate growth, development, differentiation and a number of physiological processes, e.g., auxin, gibberellins, abscisic acid, cytokinins.

  1. Hormone That Promotes Growth. Auxin/Gibberellin.
  2. Hormone That Inhibits Growth. Abscisic acid or ABA
  3. Hormone That Promotes Cell Division. Cytokinin.
  4. Hormone That Promotes Growth of a Tendril Around a Support. Auxin.

(b) A-Pons Function: Relay centre, pneumotaxic area of respiratory centre.
B-Medulla Function: Reflex centre, cardiac centre, respiratory centre.
C-Cerebellum Function: Maintains equilibrium and coordinates muscular activities

How do tendrils reach the support when they do not have any sensory structures.

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Answer :

Tendrils do not have any sensory structures but still they are able to find their support just as we grope in the dark for finding the switch-board. Tendrils perform circumnutation from their apical regions. In this the terminal parts of tendrils move in all directions. Wherever they come in contact with a support, they stop performing cicumnutation. Instead, the contacted region shows little growth while the other side grows rapidly so that the tendril coils over the support.

Name the nervous system which controls the functioning of internal organs. How does this system work ?

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Answer :

Autonomous or visceral nervous system. The system does not consult the will of the individual. It works on its own inputs. Autonomous nervous system consists of only motor nerve fibres that innervate all organs and glands of the body. Depending upon the input, autonomous nervous system stimulates, slows down or stops the activity of an organ. For its working, autonomous or visceral nervous system has two components, sympathetic and parasympathetic. Sympathetic nervous system originates from thoracico-lumbar region, forms two ganglionic chains which send out long nerve fibres to various organs. The sympathetic nerve fibres activate the organs by release of nor-adrenaline. Parasympathetic nervous system is called cranio-sacral as it originates from some cranial and sacral nerves. It has long preganglionic fibres and ganglia attached to organs that are innervated. Its post ganglionic fibres secrete acetylcholine into organs for moderating or reducing their activity.

Column A

Column B

(a) Olfactory receptors

(i) Tongue

(b) Thermo receptors (temperature receptors)

(ii) Eye

(c) Gustatoreceptors

(iii) Nose

(d) Photoreceptors

(iv) Skin

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Answer :

Column A

Column B

(a) Olfactory receptors

(iii) Nose

(b) Thermo receptors (temperature receptors)

(iv) Skin

(c) Gustatoreceptors

(i) Tongue

(d) Photoreceptors

(ii) Eye

Column I

Column II

(i) Thyroxin

(a) Puberty

(ii) Chemotropism

(b) Adrenaline

(ii) Body posture

(c) Tendril

(iv) Negative geotropism

(d) Gustatory

(v) Estrogen

(e) Goitre

(vi) Response to touch

(f) Cerebellum

(vii) Cell division

(g) Shoot system

(viii) Emergency situations

(h) Pollen tube

(ix) Taste

(i) Cytokinin

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Answer :

Column I

Column II

(i) Thyroxin

(e) Goitre

(ii) Chemotropism

(h) Pollen tube

(ii) Body posture

(f) Cerebellum

(iv) Negative geotropism

(g) Shoot system

(v) Estrogen

(a) Puberty

(vi) Response to touch

(c) Tendril

(vii) Cell division

(i) Cytokinin

(viii) Emergency situations

(b) Adrenaline

(ix) Taste

(d) Gustatory

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The CBSE Books for class 10 are designed as per the syllabus followed Gujarat Secondary and Higher Secondary Education Board provides key detailed, and a through solutions to all the questions relating to the GSEB textbooks.

The purpose is to provide help to the students with their homework, preparing for the examinations and personal learning. These books are very helpful for the preparation of examination.

For more details about the GSEB books for Class 10, you can access the PDF which is as in the above given links for the same.

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