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

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

Q1. Give the function(s) of the following plant hormones:

a. Auxins b. Gibberellins c. Cytokinins d. Abscisic acid e. Ethylene

Ans .

a. Auxins promote cell elongation, root formation, cell division, etc. It also promotes 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

Q2. Mention one function for each of these hormones.

i) Thyroxine

ii) Insulin

iii) Estrogen

iv) Growth hormone

v) Testosterone.

Ans. (i) Thyroxin – Control overall metabolic rate of the body (carbohydrate, protein and fat metabolism)

(ii) Insulin – Conversion of glucose to glycogen in liver and muscles, thus decreases blood glucose level.

(iii) Estrogen – Development of female sex organ and secondary sexual characteristics like development of breast, pimples, shrill and a higher pitch voice

(iv) Growth hormone – Body growth and development of bones.

(v) Testosterone – Development of male sex organ and secondary sexual characteristics like moustache, beard & voice.

Q3 Describe the function of the cerebellum in the brain.

Answer: The cerebellum is a region located at the base of the brain, primarily responsible for coordinating voluntary movements and maintaining posture and balance. It receives sensory input from the inner ear, muscles, and joints, allowing it to monitor body position and movement. The cerebellum then integrates this information with motor commands from the cerebral cortex to ensure smooth, coordinated movements. Additionally, the cerebellum plays a role in motor learning and refining motor skills through practice and repetition. Overall, the cerebellum is crucial for precise and coordinated movement control.

Q4. State the function of: a. gustatory receptors b. olfactory receptors

Ans:

a. Gustatory receptors:

Detect chemical stimuli related to taste.

Located on taste buds in the oral cavity.

Respond to various taste molecules like sweet, sour, salty, bitter, and umami.

Allow organisms to perceive and differentiate between different tastes.

b. Olfactory receptors:

Detect chemical stimuli related to smell.

Located in the olfactory epithelium of the nasal cavity.

Respond to odor molecules present in the air.

Initiate electrical signals transmitted to the brain.

Interpretation of signals results in perception of different smells.

Q5 Name the hormones secreted by the following endocrine glands and specify one function of each: (a)  Thyroid (b) Pituitary (c) Pancreas

 Ans :

a. Thyroid: Secretes Thyroxin. It regulates metabolism of carbohydrates, fats and proteins.

 b. Pituitary: Secretes growth hormone. Growth hormone regulates growth and development of body.

c. Pancreas: Secretes insulin. Insulin lowers blood sugar level.

Q6. State how concentration of auxins stimulates the cells to grow longer on the side of shoot which is away from light?

Ans : 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 bends towards light.

Q7. Give the function(s) of the following plant hormones:

a. Auxins

b. Gibberellins

 c. Cytokinins

 d. Abscisic acid

e. Ethylene

Ans : 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.

Q8 What are hormones? Name the hormone produced by thyroid gland and state its function.

Ans :  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.

Q9. a.If the cerebellum is not functioning properly, what are the activities of our body affected?

 b. How do muscle cells move? 

ans:

a. Effects of Cerebellum Dysfunction:

Impaired coordination and balance.

Difficulty in precise and coordinated movements.

Problems with posture and gait.

Tremors or involuntary muscle movements.

Difficulty in motor learning and executing skilled movements.

b. Muscle Cell Movement:

Muscle cells move through the contraction and relaxation of muscle fibers.

Contraction occurs when actin and myosin filaments within the muscle fiber slide past each other, shortening the muscle.

This process is triggered by the release of calcium ions, which bind to regulatory proteins and allow the actin and myosin to interact.

Energy in the form of ATP is required for this process.

Relaxation occurs when the calcium ions are pumped back into storage, allowing the muscle fibers to return to their resting state.

Q10. (a) What is reflex arc?

(b) What are the components of reflex arc?

(c) How do muscle cells move?

Ans : a. 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.

b. Stimulus ” Receptors ” Sensory neurons ” Spinal cord ” Motor neurons ” Effector.

c. 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.