Control & Coordination

Exemplar Problems

Short Answer Questions

Question 34: Label the parts (a), (b), (c) and (d) and show the direction of flow of electrical signals in the following figure.

Answer:

1. Sensory neuron
2. Spinal cord
3. Motor neuron
4. Effector

Question 35: Name the plant hormones responsible for the following

1. Elongation of cells
   Answer: Auxin
2. Growth of stem
   Answer: Giberellin
3. Promotion of cell division
   Answer: Cytokinin
4. Falling of senescent leaves
   Answer: Abscissic acid

Question 36: Label the endocrine glands in the given figure.

Answer:

1. Pineal gland
2. Pituitary gland
3. Thyroid gland
4. Thymus

Question 37: In the given figures, (a), (b) and (c), which appears more accurate and why?

Answer: Figure (a) appears more accurate because it is showing positive geotropic movement in roots and negative geotropic movement in stem.

Question 38: Label the parts of a neuron in the given figure.

Answer:

1. Dendrites
2. Cyton
3. Axon
4. Axon terminals

Question 39: Match the terms of Column (A) with those of Column (B)

Answer:

Question 40: What is a tropic movement? Explain with an example.

Answer: Tropic Movement: The movements which are in a particular direction in relation to the stimulus are called tropic movements. Tropic movements happen as a result of growth of a plant part in a particular direction. For example; the shoot usually grows in the direction of sunlight. This is called positive phototropic movement.

Question 41: What will happen if intake of iodine in our diet is low?

Answer: Iodine is an important constituent of thyroxine. Thyroxine governs the rate of general metabolism in the body. Lack of iodine in the diet can hamper general metabolism; which can lead to many complications. Moreover, deficiency of iodine also leads to a condition which is known as goiter. This manifests in the form of a permanent swelling in the neck.

Question 42: What happens at the synapse between two neurons?

Answer: Transmission of nerve impulses between two neurons takes place at through the synapse. The axon terminal of a neuron releases specialized chemicals; called neurotransmitters. These chemicals travel through the synapse and reach the dendrites of the next neuron. The nerve impulses travel along with the neurotransmitters.

Question 43: Answer the following:

1. Which hormone is responsible for the changes noticed in females at puberty?
   Answer: Oestrogen
2. Dwarfism results due to deficiency of which hormone?
   Answer: Growth hormone
3. Blood sugar level rises due to deficiency of which hormone?
   Answer: Insulin
4. Iodine is necessary for the synthesis of which hormone?
   Answer: Thyroxine

Question 44: Answer the following:

1. Name the endocrine gland associated with brain?
   Answer: Pineal Gland
2. Which gland secretes digestive enzymes as well as hormones?
   Answer: Pancreas
3. Name the endocrine gland associated with kidneys?
   Answer: Adrenal Gland
4. Which endocrine gland is present in males but not in females?
   Answer: Testis