RBSE Solutions for Class10 Science Chapter 6 Control and Coordination

These solutions have been prepared by experienced teachers.

If you are preparing for RBSE class 10 board exams, then these solutions of intext and end exercise questions will help you a lot.

These solutions cover a complete syllabus and will let you solve homework and assignments in an easy way.

 

Board	RBSE
Subject	Science
Chapter	Control and Coordination
No. of Intext questions	14
No. of End exercise questions	12
Prescribed Book	NCERT Science

 

 

Control and Coordination 

 

Answers of Questions on Page 105

Q.1 What is the difference between a reflex action and walking?

Answer

Difference between Reflex action and walking

 

Reflex Action	Walking
A reflex action is an automatic and rapid response to a stimulus.	Walking is a voluntary action.
Spinal cord is involved in it.	It is a conscious and deliberate action i.e. it is done after a thought is processed by the brain.
No thinking or feeling involve in controlling the action.	we have acquired through learning
Spinal cord is involved in this.	It is directly controlled by hind-brain
Our eyes close when bright light falls on it, a knee-jerk are examples of reflex action.	Walking in a straight line, riding a bicycle, picking up a pencil

 

 

Q.2 What happens at the synapse between the neurons?

Answer

Synapse is a very small gap between the last portion of

axon of one neuron and the dendron of the other neuron. 

At the synapse the two neurons join together. It acts as A

one way valve to transmit impulses.

 Synapse performs the following tasks:

1. It allows the information to pass from one neuron to another.

2. It ensures the passage of nerve impulse in one direction only.

 

Q.3Which part of the brain maintains posture equilibrium of the body?

Answer  

Cerebellum (a part of hind brain) maintains the posture

and equilibrium of the body.

 

Q.4 How do we detect the smell of an agarbatti (incense sticks)?

Answer     

Olfactoreceptors (in nose) send the information about the

smell of incense stick to fore-brain where olfactory lobes

of fore brain analyse and produce the sensation of smell.

The for-brain interprets it along with information

received from other receptors as well as with information

that is already stored in the brain.

 

Q.5 What is the role of the brain in reflex action?

Answer    

Reflex action is completed by spinal cord. There is no

role of brain in reflex action.  These involuntary actions

are controlled by the spinal cord which takes 

placeimmediately without thinking. However impulse or

input also goes to the brain.

 

Answers of Questions on Page 108

Q.1 What are plant hormones?

Answer   

Plant hormones are also called phytohormones. They are

the chemical substances which help in controlling

growth, flowering, height, development of plants and

their response to the environment.

 Following are the main phytohormones –

  i).  auxins, 

 ii). Gibberllins

 iii). Cytokinins  

 iv). abscisic acid

 v).ethylene.

 

Q.2 How is the movement of leaves of the sensitive plants different from the movement of a shoot towards light?

Answer

Movement of leaves in sensitive plant	Movement of shoot
1 Movement of leaves of sensitive   plant is independent of growth	1 movement of a shoot towards light depends on  growth
2 Touch is the  stimulus.	2Light is the stimulus.
3 This movement is caused by sudden loss of water.	3 This movement is caused by an unequal growth.

 

 

 

Q.3 Give an example of a plant hormone that promotes growth.

Answer  

Plant hormone auxin and gibberellins promote growth of

plant.

 

Q.4 How do auxin promote the growth of a tendril around a support?

Answer   

Auxin plant hormone is found at the tip tendril When the

tip of a tendril touches a support, then the auxins present

in its tip move to that side of tip which is away from the

support and  So, due to more auxins in it, the side of

tendril away from the support grows faster  than the side

which is in contact with the support that’s why the tendril

 bend) around the support.

 

Q.5 Design an experiment to demonstrate hydrotropism.

Answer   

The movement of plant parts towards the availability of

water is called hydrotropism. Roots always move toward

water.

we plant tiny seedling in two different trough A  and B.

Near them we place a clay pot filled with water. We water

the soil in trough A daily but Do not water the soil in

trough B. Leave both the troughs for a few days.

After a few days we dig up the seedlings carefully 

fromboth the troughs without damaging their roots. We

find that the root of seedling in trough A is straight. On

the other hand, the root of seedling in trough B got bent

towards the clay pot containing water.

This experiment shows that the root of a plant grows

towards water.

 

Answers of Questions on Page 111

Q.1 How does chemical coordinated take place in animals?

Answer  

Chemical coordinated takes place in animals by 

secretinghormones from endocrine glands.

 

Q.2 Why is the use of iodised salt advisable?

Answer 

Iodine is essential for the synthesis of thyroxin.

Deficiency of iodine in the body causes swollen neck or

through which called goiter.

 

Q.3 How does our body response when adrenalin is secreted into the blood?

Answer    

Adrenalin hormone is secreted by endocrine gland

‘Adrenal’, located on each kidney. When adrenalin

hormone is secreted into blood, heart beat become faster

to supply more oxygen to muscles, but at the same time

blood supply is reduced to digestive system and skin, so

breathing rate increases. This leads the animal (human)

body to deal with the adverse condition.

 

Q.4 Why are some patients of diabetes treated by giving injections of insulin?

Answer 

Diabetes is caused by deficiency of Insulin hormone.

Insulin regulated sugar metabolism. When amount of

insulin decreases in blood, it leads to high sugar level in

blood that’s why, patient of diabetes are treated by giving

injections of insulin.

 

Answers of End Exercise  Questions 

Q.1 Which of the following is a plant hormone?

  (a)  Insulin              

  (b)  thyroxin

  (c)  Oestrogen            

  (d)  cytokinin

 

Answer.      (d)  cytokinin

 

Q.2 The gap between two neurons is called a

   (a)  Dendrite      

   (b)  synapse

   (c)  Axon           

   (d)  impulse

 

Answer    (b)  synapse

 

 

Q.3 The brain is responsible for

  (a)  Thinking           

  (b)  regulating the heart beat

  (c)  Balancing the body   

  (d)  all of the above

 

Answer    (d)  all of the above

 

Q.4 What is the function of receptors in our body? Think of situations where receptors don’t work properly. What problems are likely to arise?

Answer    

Receptors – These are the nerve cells which receive

information from surrounding environment, are called

receptors.

    

 

Stimulus/information	Receptors
Smell	Olfactoreceptors
Taste	Tangoreceptors
Light	Photo receptors
Pain	Algesireceptors
Sound	Phono receptors

 

 

       When any receptor does not work properly, we will not be able to respond any stimulus or changes in our surrounding.

For example – In cold, our nose does not work properly,

we are not able to detect any smell and taste of food

properly because our olfactory receptors do not work

properly at this time.

 

Q.5 Draw the structure of neuron and explain its function?

Answer 

   Structure of Neuron

      

Function of a neuron :-

The information passing through neurons is in the form of chemical and electrical signals are called nerve impulse.

Dentrite receive information of change (stimuli) in surrounding and sensory neuron transmit this information to the central nervous system.  This information travels in form of an electrical impulse. This impulse travels from dentrite to the cell body and then along the axon to its end. 

At the end the electrical impulse changes into chemicals which reach the dentrites of other nerve cell where they create electrical impulse. The gap between two nerve cells is called synapse.  In this way impulse travel in body.

Q.6 How does phototropism occur in plants?

Answer  

We take a conical flask filled half with water and cover

the neck of the flask a wire mesh.  Now we keep two -

three germinated been seeds on the wire mesh in such a

way that water is in contact of germinated seeds. 

Now we keep the flask in a cardboard in such a manner

that the open side of the box faces light from window.

After two or three days we see that shoot turns towards

the light and roots moves away from the light.

Now we turn the flask away from the sun and roots

towards the sun and keep it for four to five days. After

that we see the flask the shoot turns again towards the

light and roots moves again away from light. This shows

the phototropism. 

 

Q.7 Which signals will get disrupted in case of spinal cord injury?

Answer      

Spinal cord carries messages to brain and from brain to

effector organs. In case of spinal cord injury the signals

for reflex action and motor nerves connected to the

receptor and this part will get disrupted.

 

Q.8 How does chemical coordination occur in plants?

Answer  

Plants do not have any nervous system so all the

coordination are conducted by chemicals. These

chemicals are called plant hormone.

Plants respond to light, water, gravity and other

chemicals. Auxins, gebberellins, cytokinins and abscisic

acid etc

 

Q.9 What is the need for a system of control and co-ordination in an organism?

Answer    

Our body performs different kinds of activities and

during these activities different organs work in

coordination. For example, when we take food, our eyes

locate the food, our nose detects the smell, our hand

brings the food to our mouth, the teeth and jaw muscles

chew the food and saliva starts the digestive process.

 

Q.10How are involuntary actions and reflex actions different from each other?

Answer  

Involuntary actions: - The actions which are performed

without the will of organism but controlled by the brain

are called involuntary actions such as salivation, heart

function, blood pressure breathing etc.

Reflex action: - The action which is spontaneous and

automatic without the response of brain and the will of

organism such removing of hand when a pin is pierced to

it.

 

Q.11Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.

Answer     

Comparison and contrast between nervous and hormonal

mechanism

 

Nervous mechanism	Hormonal mechanism
(i)This is performed by nervous system. (ii)      Information (impulses) is received by receptors and acts through effectors. (iii)  Chemical change occurs in the cellular composition of muscular cells. (iv)   It is related to control and coordinate the functions.	This is a performed by chemical substances called hormones. These hormones are secreted by endocrine glands.   Hormones produced in on part of the organism, move to other part of body. It is also related to control and coordination.

 

 

Q.12 What is the difference between the manner in which movement in the sensitive plant and movement in our legs takes place?

Answer   

When a part sensitive plant is touched. The information

that the plant has been touched is communicated from

cell to cell using electrical and chemical means, but plants

have no specialized tissue for the conduction of

information. Finally the cells should change their shape.

It is performed by change in amount of water.

 In animals, movement of legs is controlled by nervous

system. Movement in legs is a voluntary action. When

we think to move our legs, the brain takes action based

on thinking. Forebrain is associated where the sensory

information is interpreted by putting it together with

information from other receptors as well as the

information already stored in the brain. On this basis

decision is taken and information already stored in the

brain. On this basis decision is taken and information is

passed to motor area which controls the movement of

voluntary muscles.

 

Movement in a sensitive  plant	Movement in legs of a human
1. The leaves of a sensitive plant like are sensitive to touch. Eg. mimosa	1. Our leg is in control of nerve muscles.
2. This is not controlled by any part of the plant.	2. This 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.