"AKC SCIENCE CLASSES"
CLASS 10 TH (CBSE AND MP BOARD)
CHAPTER 07
CONTROL AND COORDINATION
INTEXT QUESTIONS AND ANSWERS
NCERT INTEXT QUESTIONS (PAGE NO. 119)
Q.01:- What is the difference between a reflex action and walking ?
Ans:-
| SL No. | Reflex action | Walking |
|---|---|---|
| 1 | Reflex action is a spontaneous immediate response to a stimulus. It happens without thinking. | Walking is a response to the information transmitted by nerve to muscles of the legs. In this case, thinking is involved. |
| 2 | Reflex action is controlled and coordinated by spinal cord. | Hind-brain instructs and controls leg muscles to move. |
| 3 | It is an involuntary action. | It is a voluntary action. |
Q.02:- What happens at the synapse between two neurons?
Ans:- At synapse, information carrying neuron's axon end, electrical impulse sets off the release of some chemicals (neuro-transmitter). These chemicals across the gap or synapse and reach to dendrites of the next neuron and start electrical impulse there.
Q.03:- Which part of the brain maintains posture and equilibrium of the body?
Ans:- Posture and equilibrium of the body are controlled by a part of the hind-brain called the cerebellum.
Q.04:- How do we detect the smell of an agarbatti (incense stick)?
Ans:- Smell of an agarbatti is sensed by receptor in the nose and information is transmitted to olfactory lobe located in the fore-brain which interpret the information.
Q.05:- What is the role of the brain in reflex action?
Ans:- Nerves form all over the body meet in a bundle in the spinal cord on their way to the brain. Reflex arcs are formed in the spinal cord itself, although the information input also goes on to reach the brain. The brain may store the experience for future.
NCERT INTEXT QUESTIONS (PAGE NO. 122)
Q.01:- What are plant hormones?
Ans:- Plant hormones are special chemical compounds released by different parts of the plant. They help to coordinate growth, development and responses to the environment. They are synthesised at places away from where they act and simply diffuse to the area of action.
Q.02:- How is the movement of leaves of the sensitive plants different from the movement of a shoot towards light?
Ans:- Difference between the movement of leaves of the sensitive plant and movement of shoot towards light :-
(ⅰ) Movement of leaves of the sensitive plant is not directional to the stimulus of touch. But the movement of shoot is directional towards light.
(ⅱ) Movement of leaves (drooping down) of sensitive plant is due to the change in the amount of water present in them. The movement of the shoot towards light is due to growth controlled by growth hormone called auxin.
Q.03:- Give an example of a plant hormone that promotes growth.
Ans:- Auxin promotes growth of cell, gibberellins help in growth of stem, cytokinin promotes cell division (any one of them).
Q.04:- How do auxins promote the growth of a tendril around a support?
Ans:- The tendrils are sensitive to touch. When a part of tendril comes in contact of a support, the growth hormone auxin diffuses from the site. This causes growth in the part of the tendril to circle around the support. Thus, the tendril cling to the support.
Q.05:- Design an experiment to demonstrate hydrotropism.
Ans:- Experiment to demonstrate hydrotropism :- Growth movements in response to the stimulus of moisture (water) are termed as hydrotropic movements (hydrotropism).
Experiment :- Place some ready to germinate seeds of pea/gram/bean in moist sawdust in a shallow box whose bottom has been replaced by a wire gauze.
keep the apparatus undistributed for 2-3 days. Keep the sawdust moist.
NCERT INTEXT QUESTIONS (PAGE NO. 125)
Q.01:- How does chemical coordination take place in animals?
Ans:- Animal hormones are directly poured into the blood by the endocrine glands. Thus, a hormone reaches to the target organ/tissues/cells. The cells have special molecules on their surface to detect these chemical compound and recognise the information a particular hormone carrying. Then the cells act accordingly.
Q.02:- Why is the use of iodised salt advisable?
Ans:- Importance of iodised salt :- Iodine is necessary for the synthesis of thyroxin hormone by the thyroid glands. Thyroxin regulates carbohydrate, protein and fat metabolism in the body. Its balanced secretion promotes proper growth. A deficiency of iodine in our diet may lead to goitre, i.e., swollen neck and other metabolic disorders.
Iodine is needed in vary small quantity to synthesis thyroxin. Iodised common salt contains proper content of iodine. To avoid deficiency of iodine, iodised salt is recommended.
Q.03:- How does our body respond when adrenaline is secreted into the blood?
Ans:- Adrenaline :- Adrenaline is secreted by adrenal glands. Adrenaline is secreted by medulla of adrenaline and poured directly into the blood.
Functions of adrenaline :-
- The target organ of adrenaline is heart. It increases rate of heart beat in order to heart beat in order to supply more oxygen to our muscles.
- The blood supply reduces to the digestive organ system, skin is reduced due to contraction of muscles around small arteries in these organs. This diverts the blood to our muscles.
- Adrenaline hormone also causes increase in breathing rate. This happens because of the contraction of muscles of the diaphragm and the ribs.
Q.04:- Why are some patients of diabetes treated by giving injections of insulin?