CBSE Class 10 Science Biology Control and Coordination Assignment

MCQ Questions for Class 10 Science Control and Coordination :-

SHORT ANSWER QUESTIONS

Question : Name the hormones secreted by the following endocrine glands and specify one function of each:
(a) Thyroid (b) Pituitary (c) Pancreas
Answer : a. Thyroid: Secretes Thyroxine. It regulates metabolism of carbohydrates, fats and proteins.
b. Pituitary: Secretes growth hormone. Growth hormone regulates growth and development of body.
c. Pancreas: Secretes insulin. Insulin lowers blood sugar level.

Question : How does chemical coordination occur in plants? Explain with the help of three examples.
Answer : In plants, chemical coordination occurs through various Phytohormones.
a. Auxins secreted by growing tissues. They provide growth of plants.
b. Gibberellins cause stem elongation, seed germination and flowering.
c. Cytokinin’s present in areas of actively dividing cells like fruits, seeds. Promote cell division.
d. Abscisic acid inhibits growth and respond to environmental stress.

Question : (a) An old man is advised by his doctor to take less sugar in his diet. Name the disease from which the man is suffering. Mention the hormone due to imbalance of which he is
suffering from this disease. Which endocrine gland secretes this hormone?
(b) Name the endocrine gland which secretes growth hormone. What will be its effect on a person if there is: (i) Deficiency of growth hormones
(ii) Excess secretion of growth hormones?
Answer : a. The man is suffering with the disease Diabetes. Insulin is the hormone which is
responsible for this disease. Pancreas secretes this hormone.
b. Pituitary gland.
(i) Deficiency of growth hormone causes dwarfism.
(ii) Excess secretion of growth hormone cause gigantism in a person.

Question : Draw and label a Neuron. Explain how it carries messages.
Answer : Information from the environment is detected by dendritic tip of a neuron located in the sense organ. A chemical reaction sets off here and it creates an electrical impulse which travels from dendrite to cell body and then along the axon to its endings where it sets off the release of some chemicals. The chemicals cross the synapse and set off a similar electrical impulse in dendrites of next neuron.Another synapse at the end of its axon delivers the impulse to the other cells like muscles cells / glands (effector organs) which react to perform the action.

Question :(a) Name the part of brain which controls :
(i) voluntary action (ii) involuntary action.
(b) What is the significance of the peripheral nervous system? Name the components of this nervous system and distinguish between the origin of the two.
Answer : .a.(i) Voluntary actions - cerebellum; (ii) Involuntary action — medulla oblongata.
b. The communication between the central nervous system and the other parts of the body is facilitated by the peripheral nervous system. Cranial nerves arise from the brain; spinal nerves arise from the spinal cord.

LONG ANSWER QUESTION

Question : Draw a labelled diagram of human brain. Discuss functions of cerebrum, cerebellum and medulla.
OR
Draw and describe the role of various parts of human brain.
Answer : Human brain has three major parts:
a. Fore-Brain contains mainly cerebrum b. Mid-brain c. Hind-brain

Functions: a. Cerebellum which controls posture, balance of body and accurate voluntary movements.
b. Pons regulates respiration
c. Medulla oblongata which controls involuntary actions like blood pressure, salivation, vomiting etc.

Question : Give the function(s) of the following plant hormones:
a. Auxins b. Gibberellins c. Cytokinins d. Abscisic acid e. Ethylene
Answer : .a. Auxins promote cell elongation, root formation, cell division, etc. It also promotes fruit growth.
b. Gibberellins stimulate stem elongation, seed germination and flowering.
c. Cytokinins help in breaking the dormancy of seeds and buds. They delay ageing in leaves.
They also promote the opening of stomata.
d. Abscisic acid promotes falling of leaves and fruits.
e. Ethylene promotes ripening of fruits

Question : (a) Draw the structure of a neuron and label the following on it:
Nucleus, Dendrite, Cell body and Axon.
(b) Name the part of neuron :
(i) Where information is acquired.
(ii) Through which information travels as an electrical impulse.
Answer : (a) 

b. (i) Dendrite (ii) Axon

Question : Describe an activity to illustrate the phenomenon of phototropism and explain why does this occur.
Answer : 

a. Take a plant and make such an arrangement that it receives the light coming from a window as shown in the figure and observe it for few days.
b. Now,turn the flask so that the shoots are away from light and the roots towards light.
Leave it undisturbed in this condition for a few days.
c. Again, observe carefully to find the difference in the movement.
d. When growing plants detect light, auxin, synthesized at the shoot tip, helps the cells to grow longer. Auxin always diffuses towards the shady side of the shoot. This concentration of auxin stimulates the cells to grow longer on the side of the shoot which is away from light. Thus, the plant appears to bend towards light.

Question :  (a) What is Phototropism and Geotropism? With labelled diagrams describe an activity to show that light and gravity change the direction that plant part grows in.
(b) Mention the role of each of the following plant hormones:
(i) Auxin (ii) Abscisic acid.
Answer : a. Phototropism It is tropic movements in the direction of light or away from it e.g. shoots bend towards light while roots grow away from it. Hence shoot is positively phototropic and root is negatively phototropic.

Geotropism: Growth of roots downward towards the earth hence positively geotropic whereas stem grows upward, away from earth, hence it is negatively geographic.
b. Auxins: Synthesized at the shoot tip, helps the cells to grow longer.
Abscisic acid: Inhibits growth, causes wilting and falling of leaves.

1. Name or give one term for the following
a) Branched protoplasmic extension of the cell body
b) Part of the brain that coordinate muscular activity
2. Give an example for plant hormone that promotes the growth.
3. Name the receptors for taste and smell.
4. Why is the use of iodised salt advisable?
5. Which part of the brain maintains posture and equilibrium of the body?

TWO MARK QUESTIONS

6. What are
a) Cranial nerves
b) Spinal nerves
7. What are synapses? What happens at the synapse between two neurons?
8. Define the terms
1. Phototropism
2. Geotropism
3. Chemotropism

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