Science | Class 10 | Question Bank Solutions; Chapter 7: Control And Coordination.

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Chapter 7: Control and Coordination (HSLC Exam Questions):

(i) The plant hormone which stimulates cell division is –
[HSLC’ 15]
(a) Auxin
(b) Cytokinin ✅
(c) Abscisic acid
(d) Gibberellin

(ii) The part of the brain which is responsible for maintaining equilibrium and posture of the body is –
[HSLC’ 16, ’19]
(a) Cerebellum ✅
(b) Medulla
(c) Pons
(d) Cerebrum

(iii) The hormone which causes wilting of leaves is –
[HSLC’ 17]
(a) Auxin
(b) Gibberellin
(c) Abscisic acid ✅
(d) Cytokinin

(iv) The hormone produced by the pancreas that helps in regulating the blood sugar level is –
[HSLC’ 18]
(a) Adrenalin
(b) Thyroxin
(c) Insulin ✅
(d) Testosterone

(v) Which of the following disease is caused due to the insufficient secretion of thyroxin hormone?
[HSLC’ 20]
(i) Beriberi
(ii) Goiter ✅
(iii) Diabetes
(iv) Dwarfism

(vi) The growth inhibiting hormone found to be present in plants is –
[HSLC’ 22]
(i) Auxin
(ii) Gibberellin
(iii) Cytokinin
(iv) Abscisic acid ✅

(vii) The gap between the two neurons is called a –
[HSLC’ 23]
(a) Dendrite
(b) Synapse ✅
(c) Axon
(d) Nerve ending

(viii) Which of the following is a plant hormone?
[HSLC’ 23]
(a) Insulin
(b) Thyroxin
(c) Oestrogen
(d) Cytokinin ✅

(ix) The gap between two neurons is called –
[HSLC’ 24]
(a) Dendrite
(b) Synapse ✅
(c) Axon
(d) Impulse

(x) Which of the following hormones promotes cell division in plants?
[HSLC’ 24]
(a) Cytokinin ✅
(b) Oestrogen
(c) Thyroxin
(d) Insulin

(xi) Some of the voluntary actions like walking in a straight line, riding a bicycle, picking up a pencil, etc., are controlled by part of the hind-brain called –
[HSLC’ 24]
(a) Cerebellum ✅
(b) Cerebrum
(c) Pons
(d) Medulla

(xii) Which of the following is a plant hormone?
[HSLC’ 25]
(a) Insulin
(b) Cytokinin ✅
(c) Thyroxin
(d) Oestrogen

(xiii) There is a herbaceous plant that grows in the wild. Its leaves have stinging hairs which cause painful stings when touched accidentally. This is due to the secretion of –
[HSLC’ 25]
(a) Hydrochloric acid ✅
(b) Methanoic acid
(c) Lactic acid
(d) Citric acid

🟩 2. Fill in the gaps:

(i) A feedback mechanism regulates the action of the ________.
👉 [HSLC’ 23]
✅ Answer: hormones

🟨 3. Determine true or false:

(i) Coliform is a group of bacteria, found in the human brain.
👉 [HSLC’ 23]
✅ Answer: False
🔹 (Coliform bacteria are found in the intestines, not in the brain. Their presence in water indicates contamination.)

4. Write the name of two types of nerve processes.

👉 [HSLC’ 15]

✅ Answer:

Dendrites
Axon

5. Give an example of chemotropism in plants.

👉 [HSLC’ 15]

✅ Answer:
Growth of pollen tube towards the ovule is an example of chemotropism in plants.
🔹 It grows in response to chemical signals released by the ovule.

6. How the amount and time of secretion of hormones are controlled?

👉 [HSLC’ 16]

✅ Answer:
The feedback mechanism of the endocrine system controls the amount and timing of hormone secretion.
🔹 It keeps hormone levels balanced in the body.

7. What are the two types of peripheral nerves?

👉 [HSLC’ 17]

✅ Answer:

Sensory nerves
Motor nerves
🔹 Sensory nerves carry messages to the brain; motor nerves carry messages from the brain to muscles.

8. What will happen if a person consumes iodine-deficient food?

👉 [HSLC’ 23]

✅ Answer:
The person may suffer from goiter, a disease caused by iodine deficiency.
🔹 It results in swelling of the thyroid gland in the neck.

Short Type Questions (Marks: 2/3)

2. How Mimosa plant responds to stimulus?
👉 [HSLC’ 15]

Answer:
When the Mimosa pudica (touch-me-not) plant is touched, its leaves fold and droop. This is a defense mechanism. The response is due to the sudden loss of turgor pressure in the cells at the base of the leaflets and petioles. The stimulus (touch) is transmitted from one part of the plant to another through chemical signals, not nerves.

3. How nervous tissue maintains muscular movement?
👉 [HSLC’ 16]

Answer:
Nervous tissue controls muscular movement by transmitting signals from the brain or spinal cord to the muscles. Motor neurons carry the electrical impulses to the muscle fibers, causing them to contract and produce movement. The coordination between sensory input and motor output helps maintain body posture and balance.

4. Why do we use iodized salt in diet?
👉 [HSLC’ 16]

Answer:
Iodized salt is used in the diet to prevent iodine deficiency. Iodine is essential for the production of thyroxine hormone by the thyroid gland. Lack of iodine can lead to a disease called goiter, which causes swelling of the neck due to an enlarged thyroid gland.

5. What is reflex? Why reflexes are developed in animals? Write the components of a reflex arc.
👉 [HSLC’ 17]

Answer:
A reflex is an automatic, quick, and involuntary response to a stimulus.
Reflexes are developed in animals to protect the body from harm and to perform quick actions without thinking.
Components of a Reflex Arc:

Receptor
Sensory neuron
Spinal cord (interneuron)
Motor neuron
Effector (muscle or gland)

6. Write the functions of adrenaline hormone.
👉 [HSLC’ 17]

Answer:
Adrenaline is secreted by the adrenal glands. It is also called the "fight or flight" hormone.
Functions:

Increases heart rate and breathing rate
Dilates pupils
Increases blood flow to muscles
Raises blood glucose levels
These changes prepare the body to face stressful situations.

7. How does nerve impulse travel in our body?

👉 [HSLC’ 18]

Answer:
Nerve impulses travel in the form of electrical signals through neurons. The impulse passes from one neuron to another via synapses using chemical messengers called neurotransmitters. These impulses are carried from receptors to the brain/spinal cord and then to effectors (muscles/glands).

8. What is an endocrine gland? What is the difference between an endocrine and an exocrine gland? Name the gland that performs both endocrine as well as exocrine functions.

👉 [HSLC’ 18]

✅ Answer:

Endocrine gland: A gland that secretes hormones directly into the blood.
Difference:
🔹 Endocrine glands are ductless (e.g., thyroid), while
🔹 Exocrine glands have ducts (e.g., salivary gland).
Mixed gland: Pancreas performs both endocrine and exocrine functions.

9. Write two differences between axon and dendrite.

👉 [HSLC’ 19]

✅ Answer:

Feature	Axon	Dendrite
Function	Carries impulses away from cell body	Carries impulses toward cell body
Number	Usually one	Usually many

10. What is hormone? Give an example of a growth-promoting plant hormone. How does movement of the leaves of a sensitive plant differ from the movement of a shoot toward light?

👉 [HSLC’ 19]

Answer:

A hormone is a chemical messenger secreted by glands in animals and plants.
Example of growth-promoting hormone: Auxin
Difference in movement:
🔹 Leaf movement in Mimosa is a nastic movement (non-directional).
🔹 Shoot bending towards light is phototropism (directional).

11. What is hydrotropism? How would you demonstrate hydrotropism with the help of an experiment?

👉 [HSLC’ 19]

✅ Answer:

Hydrotropism is a directional movement of plant roots toward moisture.
Experiment:
Place a moist cotton ball on one side of a root growing in a horizontal glass chamber. The root will bend toward the moist side, showing hydrotropism.

12. How does muscle cells change their shape?

👉 [HSLC’ 20]

✅ Answer:
Muscle cells change shape by contracting and relaxing. These actions are controlled by electrical signals (nerve impulses) that trigger sliding of actin and myosin filaments within the muscle fibers, causing movement.

13. What is the importance of iodine in our body?

👉 [HSLC’ 20]

✅ Answer:
Iodine is essential for the synthesis of thyroxine hormone by the thyroid gland.
🔹 It regulates metabolism.
🔹 Its deficiency leads to goiter, which causes swelling of the neck.

14. Name the parts of the human brain. State the activities that are controlled by the cerebellum.

👉 [HSLC’ 20]

✅ Answer:
Parts of human brain:

Cerebrum
Cerebellum
Medulla oblongata

Cerebellum controls:

Balance
Body posture
Coordination of voluntary movements

15. What is auxin? How does it aid in the growth of a plant?

👉 [HSLC’ 20]

✅ Answer:
Auxin is a plant hormone that promotes cell elongation.
🔹 It helps in the growth of stems and roots.
🔹 In phototropism, auxin moves to the shaded side of the shoot, causing it to bend toward light.

16. What is ATP? Why is it known as the energy currency for most cellular processes?

👉 [HSLC’ 21]

✅ Answer:

ATP stands for Adenosine Triphosphate.
It stores and transports energy for all cellular activities.
It is called the energy currency because it releases energy when its phosphate bonds are broken during metabolic processes.

17. With a neat labelled diagram, describe a nerve cell.

👉 [HSLC’ 22]

✅ Answer:
A nerve cell, or neuron, has:

Cell body (with nucleus)
Dendrites (receive impulses)
Axon (transmits impulses away)
Myelin sheath (insulates axon)
Axon terminals

📌 [a neat labelled diagram image of a nerve cell]

18. Describe a reflex arc.

👉 [HSLC’ 22]

✅ Answer:
A reflex arc is the pathway followed by nerve impulses during a reflex action.
It includes:

Receptor (detects stimulus)
Sensory neuron (sends message to spinal cord)
Relay neuron in spinal cord
Motor neuron (carries command to muscle)
Effector (muscle reacts)

This helps in quick and automatic response to harmful stimuli.

19. Which is the main thinking part of the brain? How can any smell be detected?

✅ Answer:

The Cerebrum is the main thinking part of the brain.
Smell is detected by olfactory receptors located in the nasal cavity. These send signals to the cerebrum for interpretation.

20. How does leaf movement of the sensitive plants differ from the shoot movement towards light?

👉 [HSLC’ 22]

✅ Answer:

Leaf movement in Mimosa pudica is a nastic movement — non-directional and in response to touch.
Shoot movement towards light is phototropism — directional growth towards the stimulus (light).
Nastic movement is fast and does not involve growth; phototropism is slow and involves growth.

21. What is a neuromuscular junction? How does a nerve impulse travel from one part to the other part of the body?

👉 [HSLC’ 22]

✅ Answer:

A neuromuscular junction is the point where a motor neuron connects with a muscle fiber.
Nerve impulse travels through neurons as electrical signals and across synapses using neurotransmitters. This allows communication between body parts and the brain.

22. Draw a neat labelled diagram of a nerve cell and state its function.

👉 [HSLC’ 23]

✅ Answer:
A nerve cell (neuron) has the following parts:

Dendrites – receive impulses
Cell body – contains nucleus
Axon – transmits impulses
Axon terminals – pass signal to next neuron

📌 Let me know if you want a labelled diagram image — I can create and send it to you.

23. Draw a nerve cell with proper labelling. How is an electrical impulse created and in which direction does this impulse travel? What function do these impulses perform?

👉 [HSLC’ 24]

✅ Answer:

Electrical impulse is created due to the difference in ionic concentration inside and outside the neuron membrane.
Impulse travels from dendrites → cell body → axon → axon terminal.
It helps in coordination and control of bodily activities by sending messages to and from the brain/spinal cord.

24. What are plant hormones? Give an example of a plant hormone that promotes growth and one that inhibits growth.

👉 [HSLC’ 24]

✅ Answer:

Plant hormones are chemical messengers that regulate plant growth and development.
Growth promoter: Auxin
Growth inhibitor: Abscisic acid

25. Name two growth-promoting hormones in plants and state their specific functions.

👉 [HSLC’ 25]

✅ Answer:

Auxin – Promotes cell elongation and phototropism.
Gibberellin – Stimulates seed germination and stem elongation.

26. Define a reflex arc.

👉 [HSLC’ 25]

✅ Answer:
A reflex arc is the pathway through which a reflex action occurs.
It includes:

Receptor → Sensory neuron → Spinal cord → Motor neuron → Effector
It allows immediate and automatic responses without involving the brain.

27. What happens when adrenaline is secreted into our blood?

👉 [HSLC’ 25]

✅ Answer:

Adrenaline prepares the body for fight or flight in stressful situations.
It increases heart rate, respiration, and glucose levels in blood to supply energy quickly to muscles.

28. Why are some of the patients of diabetes treated by giving insulin injections?

👉 [HSLC’ 25]

✅ Answer:

Diabetes is caused when the body does not produce enough insulin or cannot use it properly.
Insulin injections help in regulating blood sugar levels by allowing cells to absorb glucose from the blood.

Assertion and Reasoning Questions

(1)

Assertion (A): Our nervous system consists of numerous nerve cells or neurons.
Reason (R): The neurons carry the data from one part of the body to another part by electrical impulses and thus do their duty in the nervous system.
Options:
(a) ✅ Both (A) and (R) are true and (R) is the correct explanation of (A)
(b) Both (A) and (R) are true but (R) is not the correct explanation of (A)
(c) A is true but R is false
(d) A is false but R is true

Correct Answer: ✅ (a)

(2)

Assertion (A): The human brain sends directions to all organs, nervous system etc. of our body.
Reason (R): The required data for taking decisions by the brain are sent to the brain by the organs and nervous system of the body.
Options:
(a) ✅ Both (A) and (R) are true and (R) is the correct explanation of (A)
(b) Both (A) and (R) are true but (R) is not the correct explanation of (A)
(c) A is true but R is false
(d) A is false but R is true

Correct Answer: ✅ (a)

(3)

Assertion (A): The plants also take help of electro-chemical system for sending data from one cell to another cell.
Reason (R): The size of the plant cells do not change while responding to external touch, action or hurt.
Options:
(a) Both (A) and (R) are true and (R) is the correct explanation of (A)
(b) Both (A) and (R) are true but (R) is not the correct explanation of (A)
(c) ✅ A is true but R is false
(d) A is false but R is true

Correct Answer: ✅ (c)

(4)

Assertion (A): The brain is the most important and delicate part of the nervous system and so it is situated in a relatively safe structure.
Reason (R): Inside the bony structure there is a balloon, filled with liquid substances, so that the brain can withstand any hurt or shake.
Options:
(a) ✅ Both (A) and (R) are true and (R) is the correct explanation of (A)
(b) Both (A) and (R) are true but (R) is not the correct explanation of (A)
(c) A is true but R is false
(d) A is false but R is true

Correct Answer: ✅ (a)

(5)

Assertion (A): Though some parts of the plant may not have nerve cells or tissue cell, the parts can move also.
Reason (R): A tree can even move from one place to another place.
Options:
(a) Both (A) and (R) are true and (R) is the correct explanation of (A)
(b) Both (A) and (R) are true but (R) is not the correct explanation of (A)
(c) A is true but R is false
(d) ✅ A is false but R is true

Correct Answer: ✅ (d)

MCQs:

(i) Largest cell of the body—

(a) muscle cell
(b) blood cell
(c) ✅ nerve cell

(ii) The intermediate space between two adjacent cells—

(a) ✅ synapse
(b) axon
(c) dendrite

(iii) The number of cranial nerves in mammals—

(a) ✅ 12 pairs
(b) 24 pairs
(c) 36 pairs

(iv) The number of spinal nerves in mammals—

(a) 32 pairs
(b) ✅ 31 pairs
(c) 21 pairs

(v) Hormone was discovered by—

(a) ✅ W.M. Bayliss and A.A. Starling
(b) W. Bateson and Punnet
(c) Darwin and Harvey

(vi) The term hormone was introduced by—

(a) Starling
(b) ✅ Harvey
(c) Wayless

(vii) Axon and dendrites are found in—

(a) muscle cell
(b) ✅ nerve cell
(c) liver cell

(viii) Which of the following is not an endocrine gland—

(a) adrenal gland
(b) thyroid gland
(c) ✅ prostate gland

(ix) Diabetes causes due to—

(a) low insulin ✅
(b) low thyroxin
(c) low calcitonin

(x) Which of the following system maintain coordination among different organ systems of our body—

(a) ✅ nervous system
(b) blood circulatory system
(c) respiratory system
(d) reproductive system

(xi) Hormone is a—

(a) ✅ chemical messenger
(b) enzyme
(c) derived substance
(d) nitrogenous substance

(xii) The endocrine gland secretes—

(a) ✅ hormone
(b) enzyme
(c) plasma
(d) vitamin

(xiii) Which of the following endocrine glands control glucose level in blood—

(a) Pituitary
(b) thyroid
(c) ✅ pancreas
(d) testis

(xiv) Goitre causes due to deficiency of—

(a) growth hormone
(b) thyroid stimulating hormone
(c) ✅ thyroxine
(d) insulin

(xv) Which is known as mixed gland—

(a) thyroid gland
(b) ✅ pancreas
(c) adrenal gland

(xvi) In synapse, chemical signal is transmitted from—

(a) ✅ axonal end of one neuron to dendritic end of another neuron
(b) axon to cell body of the same neuron
(c) cell body to axonal end of the same neuron
(d) dendritic end of one neuron to axonal end of another neuron

(xvii) Which is the correct sequence of the components of a reflex arc?

(a) ✅ Receptors → Muscle → Sensory neurons → Motor neuron → Spinal cord
(b) Receptors → Motor neuron → Spinal cord → Sensory neurons → Muscle
(c) Receptors → Spinal cord → Sensory neurons → Motor neuron → Muscle
(d) Receptors → Sensory neurons → Spinal cord → Motor neuron → Muscle

(xviii) Posture and balance of the body is controlled by—

(a) Cerebrum
(b) Pons
(c) Medulla
(d) ✅ Cerebellum

(xix) Spinal cord originates from—

✅ (b) Medulla

(xx) Choose the incorrect statement about insulin—

(a) It is produced from pancreas
(b) ✅ It regulates growth and development of the body
(c) It regulates blood sugar level
(d) Insufficient secretion of insulin will cause diabetes

(xxi) Involuntary actions in the body are controlled by—

(a) Medulla in forebrain
(b) ✅ Medulla in hindbrain
(c) Medulla in midbrain
(d) Medulla in spinal cord

(xxii) Which of the following is not an involuntary action?

(a) Vomiting
(b) Salivation
(c) Heart beat
(d) ✅ Chewing

(xxiii) Junction between two neurons is called—

(a) Cell junction
(b) neuro muscular junction
(c) neural joint
(d) ✅ synapse

2. Fill in the blanks

(i) ___ cell is sensitive to changing environment.
✅ Answer: Nerve

(ii) The nervous system controls different metabolic functions in coordination with ___ system.
✅ Answer: Endocrine

(iii) The long process of nerve cell is called ___.
✅ Answer: Axon

(iv) ___ fluid is found in the cavity of spinal cord.
✅ Answer: Cerebrospinal

(v) ___ nerve carries impulses from sensory organ to central nervous system and from central nervous system to effector organ.
✅ Answer: Mixed

(vi) The motor nerve carries impulses from ___ to effector organ.
✅ Answer: Brain or Spinal cord

(vii) The autonomic nervous system controls the activity of ___ muscle.
✅ Answer: Involuntary

(viii) ___ system maintains coordination among different organs of the body and their activities.
✅ Answer: Nervous

(ix) Hormone acts as ___.
✅ Answer: Chemical messenger

(x) ___ is the smallest gland of the body.
✅ Answer: Pineal gland

(xi) The simple goitre causes due to hyposecretion of ___ hormone.
✅ Answer: Thyroxine

(xii) ___ hormone is called emergency hormone.
✅ Answer: Adrenaline

(xiii) ___ is the structural and functional unit of nervous system.
✅ Answer: Neuron

(xiv) The junction of axon and dendrite is called ___.
✅ Answer: Synapse

(xv) The nerve cell which carries information from central nervous system to effector organ is called ___ cell.
✅ Answer: Motor

(xvi) In mammals ___ pairs of cranial nerves and ___ pairs of spinal nerves are present.
✅ Answer: 12, 31

(xvii) The nerves which arise from brain are called ___.
✅ Answer: Cranial nerves

(xviii) ___ is the first discovered plant hormone.
✅ Answer: Auxin

(xix) ___ hormone inhibits the growth of lateral bud.
✅ Answer: Abscisic acid

(xx) ___ hormone helps in the elongation of plants.
✅ Answer: Gibberellin

(xxi) ___ hormone helps in the cell division of plants.
✅ Answer: Cytokinin

(xxii) The hormones which are synthesized in plants are called ___.
✅ Answer: Phytohormones

(xxiii) ___ hormone controls the apical dominance of plants.
✅ Answer: Auxin

(xxiv) Cytokinin plays a role in ___ of plants.
✅ Answer: Growth

(xxv) ___ is the most volatile and gaseous hormone.
✅ Answer: Ethylene

(xxvi) ___ hormone helps in the falling of leaves, flowers, and fruits.
✅ Answer: Abscisic acid

(xxvii) Chemically auxin is a ___.
✅ Answer: Growth hormone

3. Name the two systems of body which maintain coordination among different systems of our body.

✅ Answer:

Nervous system
Endocrine system

4. What is called nerve impulse?

✅ Answer:
A nerve impulse is an electrical signal that travels along the axon of a neuron, transmitting information from one part of the body to another.

5. What is called neuron?

✅ Answer:
A neuron is the structural and functional unit of the nervous system. It is a specialized cell that transmits nerve impulses.

6. What is called synapse?

✅ Answer:
A synapse is the junction between two neurons where the impulse is transmitted from one neuron to the next through chemical or electrical signals.

7. Name two chemical neurotransmitters.

✅ Answer:

Acetylcholine
Dopamine

8. What are the main components of peripheral nervous system?

✅ Answer:

Cranial nerves
Spinal nerves

9. Name the organs of our body whose activities are controlled by autonomic nervous system.

✅ Answer:

Heart
Lungs
Intestines
Pupil of the eye
Glands

10. What do you mean by reflex arc?

✅ Answer:
A reflex arc is the pathway followed by nerve impulses during a reflex action. It involves a receptor, sensory neuron, spinal cord, motor neuron, and effector.

11. What is called spinal nerve reflex?

✅ Answer:
A spinal nerve reflex is a reflex action controlled by the spinal cord without involvement of the brain, e.g., knee-jerk reflex.

12. What is called acquired reflex?

✅ Answer:
An acquired reflex is a learned reflex that develops with experience, such as riding a bicycle or typing on a keyboard.

13. What is called hormone?

✅ Answer:
A hormone is a chemical messenger secreted by endocrine glands that regulates various physiological activities in the body.

14. Name two hormones which are secreted by pituitary gland.

✅ Answer:

Growth hormone (GH)
Thyroid-stimulating hormone (TSH)

15. Name two hormones which are secreted by thyroid gland.

✅ Answer:

Thyroxine
Calcitonin

16. Name two adrenal hormones.

✅ Answer:

Adrenaline
Cortisol

17. Name the male and female gonad.

✅ Answer:

Male gonad: Testis
Female gonad: Ovary

18. Who first introduced the term 'hormone'?

✅ Answer:
Starling

19. Name the hormone which causes diabetes?

✅ Answer:
Insulin

20. Write down main sub-divisions of autonomic nervous system.

✅ Answer:

Sympathetic nervous system
Parasympathetic nervous system

21. Name the two sub-divisions of autonomic nervous system.

Answer:

Sympathetic nervous system
Parasympathetic nervous system

Q23. What do you mean by nervous co-ordination?

Ans: Nervous coordination is the process by which the nervous system integrates and controls the activities of different parts of the body.

Q24. Answer the following (1 mark for each)

(a) Which hormone is responsible for changes noticed in females at puberty?
Ans: Estrogen

(b) Dwarfism results due to deficiency of which hormone?
Ans: Growth hormone

(c) Blood sugar level rises due to deficiency of which hormone?
Ans: Insulin

(d) Iodine is necessary for the synthesis of which hormone?
Ans: Thyroxine

(e) Name the endocrine gland associated with brain.
Ans: Pituitary gland

(f) Which gland secretes digestive enzymes as well as hormone?
Ans: Pancreas

(g) Which endocrine gland is present in males but not in females?
Ans: Testes

Q25. Name two divisions of autonomic nervous system.

Ans: Sympathetic and Parasympathetic nervous systems

Q26. Name the disease that occurs due to deficiency of insulin.

Ans: Diabetes mellitus

Q27. Name the hormone which is commonly called "birth hormone" and "milk ejecting hormone".

Ans: Oxytocin

Q28. Name the endocrine gland which is prominent in childhood and atrophies gradually in the adult.

Ans: Thymus gland

Q29. Write the full form of EEG.

Ans: Electroencephalogram

Q30. Name male and female sex hormone.

Ans:

Male: Testosterone
Female: Estrogen

Q31. Which hormone controls water and electrolyte in the region for speech?

Ans: Aldosterone

Q32. What is neuron?

Ans: A neuron is the structural and functional unit of the nervous system.

Q33. Which lobe of cerebral hemisphere is the region for speech?

Ans: Temporal lobe

Q34. Who first introduced the term hormone?

Ans: Ernest Starling

Q35. Which hormone helps in lowering the level of blood sugar (i.e., glucose) in human being?

Ans: Insulin

Q36. Write the function of thyroxine hormone in our body.

Ans: It regulates metabolism, growth, and development.

Q37. What do you mean by plant hormone?

Ans: Plant hormones are chemical substances that control growth and other physiological functions in plants.

Q38. What is the synthetic growth regulators in plants?

Ans: 2,4-D (2,4-Dichlorophenoxyacetic acid)

Q39. Write the full name of IAA and IBA.

Ans:

IAA: Indole-3-acetic acid
IBA: Indole-3-butyric acid

Q40. What is apical dominance?

Ans: It is the phenomenon where the main central stem of the plant grows more strongly than the side branches.

Q41. Name two synthetic auxins which are used to control weed.

Ans: 2,4-D and NAA (Naphthalene acetic acid)

Q42. Name two natural cytokinin.

Ans: Zeatin and Kinetin

Q43. Name one artificially synthetic cytokinin.

Ans: Kinetin

Q44. How is seedless fruit produced?

Ans: By using growth hormones like auxins and gibberellins

Q45. What is the function of abscisic acid?

Ans: It inhibits plant growth and promotes dormancy.

Q46. Name one plant hormone which inhibits the plant growth.

Ans: Abscisic acid

Q47. In which part of the plant synthesize hormone?

Ans: Meristematic tissues (mainly shoot and root tips)

Q48. Which plant hormone helps in flowering of plants?

Ans: Gibberellins

Q49. Name the hormone which is used to produce seedless fruit.

Ans: Auxins

Q50. Define the term photoperiodism.

Ans: It is the physiological reaction of organisms to the length of day or night.

Q51. What is parthenocarpy?

Ans: The development of fruit without fertilization.

Q52. Define phototropism.

Ans: It is the growth of a plant part in response to light.

Q53. Name the plant which shows seismonastic movements.

Ans: Mimosa (Touch-me-not)

Q54. Which plant hormone promotes ripening of fruits?

Ans: Ethylene

Q55. Which part of the plant shows positive geotropism and why?

Ans: Roots, because they grow towards gravity.

Q56. Name the plant hormone that inhibits the growth of plant.

Ans: Abscisic acid

Q57. What is phytohormone? Give example.

Ans: Phytohormones are plant hormones that regulate growth.
Example: Auxin

Q58. A potted plant is made to lie horizontally on the ground. Which part of the plant will show:

(i) Positive geotropism – Ans: Roots
(ii) Negative geotropism – Ans: Shoot

Section B: Short Type Questions (Marks: 2/3)

1. How many parts in a neuron? What are the different types of nerve processes?

Ans:
A neuron has three main parts:

Cell body (cyton)
Dendrites
Axon

Types of nerve processes:

Dendrites – carry impulses toward the cell body
Axon – carries impulses away from the cell body

2. What are the different types of nerve cells?

Ans:
There are three types of nerve cells (neurons):

Sensory neurons – carry messages from sense organs to the brain or spinal cord.
Motor neurons – carry messages from the brain or spinal cord to muscles or glands.
Interneurons (relay neurons) – connect sensory and motor neurons within the brain or spinal cord.

3. Mention the function of different nerve cells.

Ans:

Sensory neurons: Receive stimuli from sensory organs and transmit them to the central nervous system (CNS).
Motor neurons: Carry instructions from the CNS to effectors like muscles and glands.
Interneurons: Process information and form links between sensory and motor neurons.

4. What is called nervous system? What are the divisions of nervous system?

Ans:
The nervous system is a complex network of neurons that coordinates and controls the activities of the body.

Divisions of the nervous system:

Central Nervous System (CNS): Brain and spinal cord
Peripheral Nervous System (PNS): Nerves outside the CNS
- Somatic Nervous System
- Autonomic Nervous System (with sympathetic and parasympathetic divisions)

5. What are the different types of nerve fibres based on the presence or absence of myelin sheath?

Ans:

Myelinated nerve fibres (have myelin sheath)
Non-myelinated nerve fibres (do not have myelin sheath)

6. What are the various types of nerve cell based on their function? Write the function of any two nerve cells.

Ans:
Types of nerve cells based on function:

Sensory neuron – carries impulses from receptors to CNS
Motor neuron – carries impulses from CNS to effectors
Interneuron – connects sensory and motor neurons

7. What are the divisions of autonomic nervous system?

Ans:

Sympathetic nervous system
Parasympathetic nervous system

8. Write the functions of sympathetic and parasympathetic nervous system.

Ans:

Sympathetic: Prepares body for action (fight or flight)
Parasympathetic: Calms the body and conserves energy

9. What is called reflex action? Give example.

Ans:
Reflex action is an automatic, quick, involuntary response to a stimulus.
Example: Withdrawal of hand from a hot object.

10. Why is pancreas called exocrine and endocrine gland?

Ans:
Because it secretes digestive enzymes (exocrine) and hormones like insulin and glucagon (endocrine).

11. How is nerve impulse conducted through reflex action?

Ans:
Through a reflex arc involving sensory neuron → spinal cord → motor neuron → effector organ.

12. Name four endocrine glands found in human body.

Ans:

Pituitary gland
Thyroid gland
Adrenal gland
Pancreas

13. Name the hormone which controls the metabolism of calcium and phosphorus and the gland from where the hormone is secreted.

Ans:
Hormone: Parathormone
Gland: Parathyroid gland

14. Name two hormones of pancreas.

Ans:

Insulin
Glucagon

15. Draw a neat labelled diagram of nerve cell.

Ans:

16. Distinguish between:

(a) Endocrine gland and exocrine gland

Endocrine: Ductless, secrete hormones into blood
Exocrine: Have ducts, secrete enzymes

(b) Diabetes mellitus and goitre

Diabetes mellitus: Caused by lack of insulin
Goitre: Caused by iodine deficiency

(c) Chemical coordination and nervous coordination

Chemical: Slow, via hormones
Nervous: Fast, via nerve impulses

(d) Sympathetic and parasympathetic nervous system

Sympathetic: Prepares body for emergencies
Parasympathetic: Calms the body

17. Why is gonad called endocrine gland?

Ans:
Because gonads secrete sex hormones (testosterone, estrogen) directly into the blood.

18. If the reflex action mechanism is absent in our body, what type of anomalies may occur?

Ans:
We would not be able to respond quickly to harmful stimuli, leading to injuries or harm.

19. What are the major parts of nerve cell?

Ans:

Cell body (cyton)
Dendrites
Axon

20. Describe the function of axon and dendrite.

Ans:

Axon: Carries nerve impulses away from cell body
Dendrite: Receives impulses and carries them to cell body

21. Name the thyroid hormone and mention their function.

Ans:
Hormone: Thyroxine
Function: Regulates metabolism and energy balance

22. Write the function of insulin hormone and its hyposecretion. Name the disease.

Ans:

Function: Regulates blood sugar
Hyposecretion causes: Diabetes mellitus

23. Why is hormone called chemical messenger?

Ans:
Because it transmits messages through blood to target organs for specific actions.

24. What will happen if intake of iodine in our diet is low?

Ans:
It may lead to goitre, a swelling of the thyroid gland.

25. Name the endocrine gland which has islets of Langerhans. Name its hormonal secretions.

Ans:

Gland: Pancreas
Hormones: Insulin and Glucagon

26. Define reflex action with suitable example.

Ans:
Reflex action is a sudden automatic response to a stimulus.
Example: Knee-jerk reaction.

27. Name the hormones secreted from ovary and mention their functions.

Ans:

Estrogen: Controls development of female secondary sexual characters
Progesterone: Prepares uterus for pregnancy

28. Nervous system and hormonal systems together perform the function of control and coordination in human beings. Justify the statement.

Ans:

Nervous system provides fast, immediate response via electrical impulses.
Hormonal system provides slow, long-term regulation via chemical messengers.
Together, they ensure body’s proper function and balance.

29.

(a) Which part of neuron receives the information?
Ans: Dendrites
(b) Name the minute gap between two adjacent neurons.
Ans: Synapse
(c) Give general name of the chemicals that transmit nerve impulse across.
Ans: Neurotransmitters

30. What are male and female gonads called in human being? Mention their functions.

Ans:

Male gonads: Testes – produce sperm and testosterone
Female gonads: Ovaries – produce eggs, estrogen, and progesterone

31. What is called apical dominance? Name the hormone that controls it.

Ans:
Apical dominance is the suppression of lateral buds by the apical bud.
Controlled by: Auxin

32. Draw a diagram of human brain and label:

Ans:

(i) Cerebrum
(ii) Meninges
(iii) Medulla oblongata
(iv) Cerebellum

33. Why do the signals in a synapse flow from axonal end of one neuron to dendritic end of another neuron but not the reverse?

Ans:
Because neurotransmitters are released only from the axon terminal, not from dendrites.

34. Name the source of secretion of following hormones:

(a) Glucagon – Pancreas
(b) Progesterone – Ovary
(c) Testosterone – Testes
(d) Relaxin – Ovary

35. What is the need for reflex action? Give one example.

Ans:
Reflex actions protect us from danger by responding quickly.
Example: Pulling hand away from hot object.

36. How many pairs of cranial nerves and spinal nerves are there in man? What is the nature of spinal nerves?

Ans:

Cranial nerves: 12 pairs
Spinal nerves: 31 pairs
Nature: Mixed (contain both sensory and motor fibres)

37. Draw a neat labelled diagram of nerve cell

Ans:

38. Write about the role of plant hormone in agriculture.

Ans:
Plant hormones are used in agriculture to:

Promote root growth (using auxins)
Delay leaf fall and fruit drop (auxins)
Ripen fruits faster (ethylene)
Produce seedless fruits (auxins/gibberellins)
Improve flowering and fruiting (gibberellins)

39. Name the five types of plant hormone.

Ans:

Auxin
Gibberellin
Cytokinin
Abscisic acid
Ethylene

40. Name one natural and three synthetic plant hormones.

Ans:

Natural: Indole-3-acetic acid (IAA)
Synthetic: 2,4-D, NAA (Naphthalene acetic acid), IBA (Indole-3-butyric acid)

41. Write down four functions of auxin hormone.

Ans:

Promotes cell elongation
Controls apical dominance
Initiates root formation
Delays fruit and leaf fall

42. Name four gibberellin hormones.

Ans:
GA₁, GA₂, GA₃, GA₄ (GA = Gibberellic Acid series)

43. Write down four functions of gibberellin hormone.

Ans:

Promotes stem elongation
Breaks seed dormancy
Stimulates flowering
Induces parthenocarpy (seedless fruits)

44. Distinguish between auxin and gibberellin.

Ans:

Feature	Auxin	Gibberellin
Discovery	First plant hormone discovered	Discovered later during study of "foolish seedling disease" in rice
Main Function	Promotes cell elongation and root initiation	Promotes stem elongation and seed germination
Apical Dominance	Maintains apical dominance (inhibits lateral buds)	Does not maintain apical dominance
Fruit Role	Delays fruit and leaf fall (prevents abscission)	Helps in fruit development and parthenocarpy (seedless fruit)
Seed Dormancy	Not directly involved in breaking dormancy	Breaks seed dormancy and stimulates germination
Examples	IAA (Indole-3-acetic acid), NAA, 2,4-D	GA₃ (Gibberellic acid), GA₁, GA₂

45. Mention four functions of cytokinin.

Ans:

Promotes cell division
Delays leaf senescence
Stimulates shoot formation
Enhances chloroplast development

46. Write the functions of abscisic acid in plant body.

Ans:

Inhibits growth
Promotes dormancy
Induces stomatal closure during water stress
Helps in leaf fall and fruit drop

47. What are seismonastic movements? Name the plant which depicts such movements in response to touch.

Ans:
Seismonastic movements are movements in response to mechanical shock or touch.
Plant example: Mimosa pudica (Touch-me-not)

48. What are nastic movements in plants? Explain what happens when we touch leaves of ‘touch-me-not’ plant and why this happens.

Ans:
Nastic movements are non-directional responses to stimuli.
Touch-me-not plant folds leaves when touched due to rapid water loss in motor cells at leaf base (seismonastic movement).

49. What is phototropism? Describe an activity to show phototropism.

Ans:
Phototropism is growth response to light.
Activity:

Take a potted plant and keep it near a window.
The shoot bends towards the light, showing positive phototropism.

50. Differentiate between tropic and nastic movements in plants. Give one example each.

Ans:

Feature	Tropic Movement	Nastic Movement
Definition	Directional growth movement in response to a stimulus	Non-directional movement in response to a stimulus
Direction of Movement	Depends on the direction of the stimulus	Independent of the direction of the stimulus
Type of Response	Slow and permanent (growth-related)	Usually fast and temporary (not growth-related)
Examples of Stimuli	Light, gravity, water, touch	Touch, temperature, light intensity
Plant Part Involved	Growing parts (shoot, root)	Non-growing parts (like leaves or petals)
Example	Phototropism – shoot bends towards light	Seismonasty – folding of Mimosa pudica leaves on touch

51. Describe how auxins are related with bending of shoots towards the source of light.

Ans:
Auxins accumulate on the shaded side of shoot, causing cells there to elongate more. This bends the shoot toward the light.

52. What do you mean by autonomic nervous system? Describe with example how it controls activity of internal organs.

Ans:
Autonomic nervous system controls involuntary functions (e.g., heartbeat, digestion).
Example: Sympathetic nerves increase heartbeat; parasympathetic slows it.

53. Name two hormones of pituitary gland and state their functions.

Ans:

Growth Hormone – Stimulates growth
Oxytocin – Helps in childbirth and milk ejection

54. (a) What is (i) phototropism (ii) geotropism?

Ans:

Phototropism: Growth of plant towards light
Geotropism: Growth in response to gravity

(With labelled diagrams)

(b) Mention the role of each of the following plant hormones:
(i) Auxin: Promotes cell elongation and root initiation
(ii) Abscisic acid: Inhibits growth, induces dormancy

C. Essay Type Questions (Marks: 4/5)

1. Describe briefly about the chemical coordination among various organs of vertebrate animals.

Ans:
Chemical coordination in vertebrates is controlled by the endocrine system. Glands like pituitary, thyroid, pancreas, etc., secrete hormones that regulate body functions such as metabolism, growth, and reproduction.

2. What is called nervous system? Write briefly about the structure and function of nervous system.

Ans:
The nervous system is a network of neurons that transmits signals between body parts.
Structure: Divided into central (brain + spinal cord) and peripheral (nerves) systems.
Function: Controls and coordinates body activities and responses to stimuli.

3. What is nerve cell? Write about structure and function of nerve cell.

Ans:
A nerve cell or neuron is the basic unit of the nervous system.
Structure: Cell body, dendrites, axon.
Function: Transmits nerve impulses throughout the body.

4. Describe briefly the structure and function of nervous system.

Ans:
Structure: CNS (brain + spinal cord) and PNS (cranial + spinal nerves)
Function: It receives stimuli, processes information, and sends responses.

5. Prepare a list of various endocrine glands of mammals and their secretion.

Ans:
| Gland | Hormone |
|---------------|----------------|
| Pituitary | Growth hormone
| Thyroid | Thyroxine
| Pancreas | Insulin, Glucagon
| Adrenal | Adrenaline
| Testes | Testosterone
| Ovaries | Estrogen, Progesterone

6. What are the main divisions of nervous system? Write about peripheral nervous system.

Ans:
Divisions:

Central Nervous System
Peripheral Nervous System (PNS)

PNS:
Consists of cranial and spinal nerves. It connects CNS to the rest of the body and includes somatic and autonomic systems.

Case Study Based Questions

Case Study Passage 1

(About the nervous system tools: brain, spinal cord, complex network of nerves; signals sent to and from body parts.)

1. What are the main tools of our nervous system?

Ans:
The main tools of our nervous system are:

Brain
Spinal cord
Network of nerves

2. Which control the functions of our body?

Ans:
The brain controls most of the functions of our body by processing and sending signals through the spinal cord and nerves.

3. What is the function of our nervous system?

Ans:
The nervous system:

Receives information from the environment
Processes it in the brain
Sends instructions to body parts for suitable action
Controls and coordinates all voluntary and involuntary activities

Case Study Passage 2

(About Binomial Nomenclature: two-word scientific naming system; first word = class or genus, second word = species.)

1. What is binomial nomenclature?

Ans:
Binomial nomenclature is a system of naming organisms using two Latin words:

The first word is the genus
The second word is the species

2. What is meant by the first word of the name?

Ans:
The first word of the name in binomial nomenclature refers to the genus of the organism.

3. What is meant by the second word of the name?

Ans:
The second word refers to the species of the organism, which identifies the specific type within the genus.

Sakil Ahmed Classes