Control and Coordination For Class 10 Biology Important Questions
Q 1 – Which plant hormone promotes dormancy in seeds and buds?
(a) Auxin
(b) Gibberellin
(c) Cytokinin
(d) Abscisic acid
(d) Abscisic acid
Q 2 – Response of plant roots towards water is called:
(a) Chemotropism
b) Phototropism
(c) Hydrotropism
(d) Geotropism
(c) Hydrotropism
Q 3 – Which plant hormone promotes cell division?
(a) Auxin
(b) Gibberellin
(c) Cytokinin
(d) Abscisic acid
(c) Cytokinin
Q 4 – Fall of mature leaves and fruits from plants is triggered by which of the following substance?
(a) Auxin
(b) Cytokinin
(c) Gibberellin
(d) Abscisic acid
(d) Abscisic acid
Q 5 – A part of the body which responds to the in-structions sent from nervous system is called
(a) receptor
(b) effector
(c) nerves
(d) muscles
(b) effector
Q 6 – The highest coordinating centre in the human body is
(a) spinal cord
(b) heart
(c) brain
(d) kidney
(c) brain
Q 7 – Breathing is controlled by which part of the brain?
(a) Cerebrum
(b) Cerebellum
(c) Hypothalamus
(d) Medulla oblongata
(d) Medulla oblongata
Q 8 – Which part of nervous system controls the re¬flex activities of the body?
(a) Brain
(b) Spinal cord
(c) Cerebrum
(d) Cerebellum
(b) Spinal cord
Q 9 – Which gland secretes the growth hormone?
(a) Pituitary gland
(b) Thyroid
(c) Hypothalamus
(d) Adrenal
(a) Pituitary gland
Q 10 – A diabetic patient suffers from deficiency of which hormone?
(a) Thyroxine
(b) Testosterone
(c) Oestrogen
(d) Insulin
(d) Insulin
Q 11 – Define‘Chemotropism’.
Chemotropism is a nastic response towards the chemicals like the germination of pollen tube when pollen grain lands on stigma.
Q 12 – What is synapse?
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.
Q 13 – 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?
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
Q 14 – Write two differences between the response of the plants and response of the animals to stimuli?
Plants | Animals |
No specific or specialized tissue present for conduction of information. | Specialised tissues are present in the body for conduction of information. |
Plant cells change shape by changing the amount of water in them. | Specialised proteins are found in muscle cells which help in changing the shape. |
Q 15 – How does feedback mechanism regulate the hormone secretion?
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.
Q 16 – How does chemical coordination occur in plants? Explain with the help of three examples.
In plants, chemical coordination occurs through various phytohormones.
- Auxins secreted by growing tissues. They provide growth of plants.
- Gibberelins cause stem elongation, seed germination and flowering.
- Cytokinins present in areas of actively dividing cells like fruits, seeds. Promote cell division.
- Abscisic acid inhibits growth and respond to environmental stress.
Q 17 – Name the hormone which is secreted by the adrenal gland. How does this hormone help to deal with the scary situations?
Adrenaline. It increase the heart rate, breathing rate so that more blood can be pumped and oxygen can be supplied to the muscles. Blood supply is cut off from skin and sent to muscles. The action of this hormone prepares the person to face the situation so that either he/she may run away or fight.
Q 18 – (i) Deficiency of growth hormones?
(ii) Excess secretion of growth hormones?
- 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.
(1) Deficiency of growth hormone causes dwarfism.
(2) Excess secretion of growth hormone cause gigantism in a person.
Q 19 – Give reasons:
- Pituitary is often termed as master endocrine gland.
- Pancreas helps in digestion and also regulates blood sugar level.
- Adrenals are known as glands of emergency.
- Pituitary is often called as master endocrine gland because it controls and coordinates the secretion of all the other endocrine glands.
- Pancreas secretes pancreatic juice as well as a hormone called as insulin. Pancreatic juice helps in digestion whereas insulin regulates blood sugar level.
- Adrenalin is secreted directly into the blood and is carried to different parts of the body. It acts on heart. As a result, the heart beats faster in order to supply more oxygen to our muscles. The blood to the digestive system and skin is reduced due to contraction of muscles around small arteries in these organs. This diverts the blood to our skeletal muscles. The breathing rate also increases because of the contractions of the diaphragm and the rib muscles. All these responses together enable the animal body to get ready to deal with the situation.
Q 20 – (a) What is reflex arc?
(b) What are the components of reflex arc?
(c) How do muscle cells move?
- The process of detecting the signal or the input and responding to it by an output action might be completed quickly. Such a connection is commonly called reflex arc.
- Stimulus → Receptors → Sensory neurons → Spinal cord → Motor neurons → Effector.
- Muscle cells have special proteins that change their shape and arrangement in the cell in response to electrical impulse. This leads the muscle cells shortening.
Q 21 – What are hormones? Name the hormone produced by thyroid gland and state its function.
Chemical coordination in animals occurs through chemicals called hormones which are secreted by endocrine glands. Thyroxin hormone. It regulates metabolism of carbohydrates, fats and proteins. It is advisable to consume iodized salt in our food as iodine is required by our thyroid gland to produce thyroxin hormone. If it lacks in our body goiter may occur due to enlargement of thyroid in the neck region.
Q 22 – Give the function(s) of the following plant hormones:
- Auxins
- Gibberellins
- Cytokinins
- Abscisic acid
- Ethylene
- Auxins promote cell elongation, root formation, cell division, etc. It also promote fruit growth.
- Gibberellins stimulate stem elongation, seed germination and flowering.
- Cytokinins help in breaking the dormancy of seeds and buds. They delay ageing in leaves. They also promote the opening of stomata.
- Abscisic acid promotes falling of leaves and fruits.
- Ethylene promotes ripening of fruits
Q 23 – a. If the cerebellum is not functioning properly, what are the activities of our body affected?
b. How do muscle cells move?
a. If the cerebellum is not functioning properly, voluntary action of our body will be affected maintaining the posture and balance of the body.
b. Muscle cells move by changing their shape so that they get shorten.
Q 24 – Tendrils encircle or coil around the object in contact with it. Elaborate.
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.
Q 25 – How is nerve impulses get transmitted across the synapse?
Neuron ending transmit the nerve impulse to dendrite of next neuron through the chemical (neurotransmitter).
Q 26 – What are hormones?
Hormones are the chemical substances secreted in trace amounts by specialised tissue called endocrine glands.
Q 27 – State how concentration of auxins stimulates the cells to grow longer on the side of shoot which is away from light?
Auxin form in the shoot tip but diffuse toward the part which is in shade/away from the light. The concentration on shady part increase stimulation cells in this part to elongate. The side of shoot on this side grows longer than the part in light hence bend towards light.