Very Short Answer-Class 10 -Science- Biology-Chapter 6 – Control and Coordination

Class 10 -Science-Very Short Answer- Biology-Chapter 6 – Control and Coordination

Q1.What is Chemotropism? Give one example. Name any two plant hormones and mention their functions.

Ans. Chemotropism is the movement of a part of the plant in response to a chemical stimulus. It can be positive chemotropism or negative chemotropism. Example: The growth of pollen tube towards a chemical which is produced by an ovule during the process of fertilisation in a flower.

Two plant hormones with their functions are as follows:

Auxins promote growth, cell elongation, cell differentiation, root formation.

Gibberellins stimulate stem elongation, seed germination

Q2(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.

Ans.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.

Q3. What are Neurons?

Neurons are specialized cells in the nervous system responsible for transmitting electrical impulses and facilitating communication between different parts of the body. They consist of a cell body, dendrites (which receive signals), and an axon (which transmits signals). Neurons play a fundamental role in processing and transmitting information, enabling various bodily functions, including movement, sensation, and cognition.

Q4 (a) Name one gustatory receptor and one olfactory receptor present in human beings.

(b)Write a and b in the given flow chart of neuron through which information travels as an electrical impulse.

Dendrite à a à bà End point of Neuron

 Ans :

(a) Tongue / Nose.

(b)  a à Cell body,  b à  axon

In the given flow chart of a neuron, the missing components are:

Dendrite –> a (Cell Body) –> b (Axon) –> End point of Neuron

Q5. What are hormones?

 Ans : Hormones are the chemical substances secreted in trace amounts by specialised tissue called endocrine glands.

Q6. Define neuron. Name the parts of the neuron where:

 a. information is acquired.

b. impulse must be converted into a chemical signal for onward transmission?

Ans :Neuron is a functional and structural unit of nervous system. These cells are specialised for conducting information via electrical impulses from one part of the body to another. (a) dendrites (b) end of axon.

Q7. a.What is synapse?

b.Define ‘reflex action’

Ans :

(a)Synapse is the functional junction between two neurons. It is a gap junction point between nerve endings of one neuron and dendrites of another neuron.

(b)Reflex action is a sudden, involuntary, spontaneous response to the stimulus that is usually helpful to protect ourselves from any kind of harm.

Q8 How does feedback mechanism regulate the hormone secretion?

Ans

The feedback mechanism regulates the timing and amount of hormone to be secreted, e.g., if a person has more sugar in his blood, this is detected by the cells of the pancreas. As a result, more insulin will be secreted to oxidise the sugar. In a reverse situation, the secretion of insulin will be reduced.

Q9. What is meant by hydrotropism? Give an example.

 Ans :The response of a plant towards water is called hydrotropism. The roots of plants show positive hydrotropism.

Q10. Define phototropism and give one example.

 Ans :Movement of plant parts towards the light is called phototropism, e.g., stem of plant usually move towards light.

Q11.Tendrils encircle or coil around the object in contact with it. Elaborate.

Ans : Tendrils are sensitive to touch. When they come in contact with any support, the part of the tendril in contact with the object does not grow as rapidly as the part of the tendril away from the object. This causes the tendril to circle around the object and thus, cling to it.

Q12. What is Endocrine system

Endocrine system is a system facilitates the communication between central nervous system and other parts of the body.

Q13. What is pituitary gland

The pituitary gland is a small gland located at the base of the brain that regulates hormone secretion and is divided into anterior and posterior lobes.

Q14. Define ‘Chemotropism’.

Chemotropism is the directional growth or movement of an organism or part of an organism in response to a chemical stimulus. This can involve movement towards or away from the source of the chemical stimulus.