CBSE Class 10 Science Control and Coordination Assignment Set 03

Very Short Answer Type Questions

Question. Write the role of motor areas in brain.
Answer: Motor areas of the brain control the movement of voluntary muscles.

Question. Give the scientific names of the following regions ofthe human brain:
a. Region for sight.
b. Region which controls salivation.
Answer: a. Temporal lobe (of the forebrain)
b. Medulla (of the hindbrain)

Question. Name the sensory receptors found in the nose and on the tongue.
Answer: Olfactory receptors, gustatory receptors.

Question. Give one example of chemotropism.
Answer: The growth of pollen tube towards ovule.

Question. Define‘Chemotropism’.
Answer: Chemotropism is a nastic response towards the chemicals like the germination of pollen tube when pollen grain lands on stigma.

Question. Name the plant hormone responsible for the promotion of cell division.
Answer: Cytokinin.

Question. All information for our environment is detected by specialised tips of some nerve cells. Write the name given to such tips and also mention where are they located?
Answer: Receptors. They are located in sense organs.

Question. State the function of:
a. gustatory receptors
b. olfactory receptors
Answer: a. To detect taste.
b. To detect smell.

Question. Which part of the nervous system controls reflex arcs?
Answer: Spinal cord.

Question. What type of movement is shown by mimosa plant leaves when touched with a finger?
Answer: Nastic movement.

Question. Which tropic movement is responsible for the growth of pollen tubes towards ovules?
Answer: Chemotropism.

Question. Which system facilitates the communication between central nervous system and other parts of the body?
Answer:  Endocrine system.

Question. Which gland secretes growth hormone in human beings?
Answer: Pituitary gland.

Question. What is synapse?
Answer: 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.

Question. Name two specialised tissues that provide control and coordination in multicellular organisms.
Answer: Nervous and muscular tissues.

Question. List two body functions that will be affected if cerebellum gets damaged.
Answer: a. Walking in a straight line.
b. Picking up a thing from the ground.

Question. Define ‘reflex action’.
Answer: Reflex action is a sudden, involuntary, spontaneous response to the stimulus that is usually helpful to protect ourselves from any kind of harm.

Question. How is nerve impulses get transmitted across the synapse?
Answer: Neuron ending transmit the nerve impulse to dendrite of next neuron through the chemical (neurotransmitter).

Question. Why endocrine glands release their secretions into the blood?
Answer: It is because endocrine glands are ductless.

Short Answer Type Questions

Question. Name the hormone which is secreted by the adrenal gland. How does this hormone help to deal with the scary situations?
Answer: 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.

Question. a. If the cerebellum is not functioning properly, what are the activities of our body affected?
b. How do muscle cells move?
Answer: 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.

Question. a. Name the hormone which is injected to a diabetic patient.
b. Why should we use iodised salt in our diet?
c. If iodine is insufficient in one’s diet, what might be the deficiency disease and its symptoms?
Answer: a. Insulin.
b. Iodine is necessary for the thyroid gland to secrete thyroxine hormone. Thyroxine regulates carbohydrates, proteins and fat metabolism in the body, to provide best balance for growth.
c. If iodine is insufficient in one’s diet, iodine deficiency disease called goitre occurs. Symptom is swollen neck.

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.
(1) Deficiency of growth hormone causes dwarfism.
(2) Excess secretion of growth hormone cause gigantism in a person.

Question. Answer the following:
a. Name the endocrine gland associated with brain.
b. Which gland secretes digestive enzymes as well as hormone?
c. Name the endocrine gland associated with kidneys.
d. Which endocrine gland is present in males but not in females?
e. Which hormone is responsible for changes in females during puberty?
f. Iodine is necessary for the synthesis of which hormone?
Answer: a. Pituitary gland,
b. Pancreas,
c. Adrenal gland,
d. Testes,
e. Oestrogen,
f. Thyroxine

Question. Name the hormones secreted by thyroid, parathyroid and pancreas.
Answer: a. Thyroid gland: It secretes thyroxine hormone.
b. Parathyroid gland: It secretes calcitonin hormone.
c. Pancreas: It secretes two hormones:
(a) Insulin (b) Glucagon

Question. Name the hormone synthesised at the shoot tips. How does it help the plant to respond to light?
Answer: Auxin is synthesised at the shoot tips when growing plant detects light and helps the cells to grow longer.
When light is coming from one side of the plant, auxin 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.  (Image 56)

Question. Give reasons:
a. Pituitary is often termed as master endocrine gland.
b. Pancreas helps in digestion and also regulates blood sugar level.
c. Adrenals are known as glands of emergency.
Answer: a. Pituitary is often called as master endocrine gland because it controls and coordinates the secretion of all the other endocrine glands.
b. Pancreas secretes pancreatic juice as well as a hormone called as insulin. Pancreatic juice helps in digestion whereas insulin regulates blood sugar level.
c. 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.

Question. The two glands A and B which occur in pairs are present in endocrine system. The pair of glands A is found only in females whereas the pair of glands B occur only in males. The gland A make and secrete hormone C whereas gland B make and secrete hormone
E. In addition to hormone, gland A makes gamete F whereas gland B makes gamete G.
a. What are glands A and B?
b. Name the hormone C and E
c. Name the gamete F and G.
Answer: a. glands A – ovaries B-testes
b. Hormone C – oestrogen E-testosterone
c. The gamete F – ova G-sperms

Question. ‘Brain and spinal cord are two vital organs of our body’. How is our body designed to protect them?
Answer: Brain is protected a bony box contained in ‘ a fluidfilled balloon which protects from shocks.
Vertebral column protects the spinal cord or both are protected by protective layers called meninges, protective fluid (CSF  → cerebrospinal fluid).

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 Throxine. It regulates metabolism of carbo¬hydrates, fats and proteins.
b. Pituitary: Secretes growth harmone. Growth harmone regulates growth and development of body.
c. Pancreas: Secretes insulin. Insulin lowers blood sugar level.

Question. State how concentration of auxins stimulates the cells to grow longer on the side of shoot which is away from light?
Answer: 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.

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. Which hormone is secreted during emergency situations like anger or excitement? How does it help the human body to handle such situations?
                                                  or
How does our body respond when adrenaline is secreted in to the blood?
Answer: Adrenaline is secreted during emergency situations.
Heart beats faster, supply of more oxygen to muscles, more blood to skeletal muscles, increased breathing rate. It provides energy to muscles to act swiftly.

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 promote 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: 

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 concentrations 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 bends 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.