Chapter 6 -Biology - Question Paper

📄 Class 10 Science — Control & Coordination | 80 Marks

Secondary School Examination

Central Board of Secondary Education (CBSE Pattern)

80

Max Marks

Science — Class X

Chapter 6: Control and Coordination

Biology · Nervous System · Plant Hormones · Endocrine System

SubjectScience (Code 086)

ClassX (Secondary)

Maximum Marks80

Time Allowed3 Hours

Chapter6 — Control & Coordination

SectionsA, B, C, D

📋 General Instructions

1. This question paper consists of four sections — A, B, C and D.
2. Section A contains 20 questions of 1 mark each. Attempt all questions.
3. Section B contains 6 questions of 2 marks each. Attempt any 5.
4. Section C contains 7 questions of 3 marks each. Attempt any 6.
5. Section D contains 3 questions of 5 marks each. Attempt any 2.
6. Draw neat, labelled diagrams wherever necessary. Marks are awarded for diagrams.
7. All parts of a question must be attempted together.
8. Write legibly. Marks may be deducted for illegible handwriting.

20

Section A
1 mark × 20

10

Section B
2 marks × 5

18

Section C
3 marks × 6

10

Section D
5 marks × 2

58–80

Total
(choose as per rules)

* Full paper = 80 marks when all questions are attempted as per the choice structure.

SECTION A

Multiple Choice Questions (MCQ) & Very Short Answer — 1 Mark Each

20 × 1 = 20 Marks

Q1–Q16: MCQ — Choose the most appropriate option.  |  Q17–Q20: One-word / one-line answer.

Q1.

The gap between two neurons is called a:

1

(a)Dendrite

(b)Synapse

(c)Axon

(d)Nerve ending

Q2.

Which of the following is a plant hormone?

1

(a)Insulin

(b)Thyroxin

(c)Cytokinin

(d)Adrenaline

Q3.

The brain is responsible for:

1

(a)Thinking only

(b)Regulating heartbeat only

(c)Balancing the body only

(d)All of the above

Q4.

Reflex arcs are formed in the:

1

(a)Fore-brain

(b)Cerebellum

(c)Spinal cord

(d)Mid-brain

Q5.

Which part of the hind-brain maintains posture and balance of the body?

1

(a)Medulla

(b)Pons

(c)Cerebrum

(d)Cerebellum

Q6.

Auxin is synthesised at which part of the plant?

1

(a)Root tip

(b)Shoot tip

(c)Leaves

(d)Seeds

Q7.

Adrenaline is secreted by which gland?

1

(a)Thyroid gland

(b)Pituitary gland

(c)Adrenal gland

(d)Pancreas

Q8.

Iodine is needed by the body for the synthesis of:

1

(a)Insulin

(b)Thyroxin

(c)Adrenaline

(d)Growth hormone

Q9.

The growth of pollen tubes towards ovules is an example of:

1

(a)Phototropism

(b)Geotropism

(c)Chemotropism

(d)Hydrotropism

Q10.

Which hormone promotes cell division and is found in high concentration in fruits and seeds?

1

(a)Auxin

(b)Gibberellin

(c)Cytokinin

(d)Abscisic acid

Q11.

Which of the following is an example of an involuntary action?

1

(a)Writing

(b)Riding a bicycle

(c)Heartbeat

(d)Moving a chair

Q12.

Deficiency of growth hormone during childhood leads to:

1

(a)Diabetes

(b)Goitre

(c)Dwarfism

(d)Gigantism

Q13.

The sensitive plant (Mimosa pudica) folds its leaves when touched. This movement is:

1

(a)Growth-dependent

(b)Growth-independent

(c)Tropic movement

(d)Geotropic movement

Q14.

Insulin is produced by the:

1

(a)Thyroid gland

(b)Adrenal gland

(c)Pituitary gland

(d)Pancreas

Q15.

Which plant hormone inhibits growth and causes wilting of leaves?

1

(a)Auxin

(b)Gibberellin

(c)Cytokinin

(d)Abscisic acid

Q16.

The spinal cord is protected by the:

1

(a)Cranium (skull)

(b)Vertebral column (backbone)

(c)Rib cage

(d)Pelvic girdle

Q17.

Name the receptor cells responsible for detecting smell.

1

Q18.

Name the hormone that helps regulate blood sugar levels in the human body.

1

Q19.

What is the term for directional growth movement of a plant in response to the pull of gravity?

1

Q20.

Which part of the fore-brain is responsible for the sensation of feeling full (hunger centre)?

1

SECTION B

Short Answer Questions — Attempt any 5 out of 6

5 × 2 = 10 Marks

Q21.

What happens at the synapse between two neurons? Why is it important?

2

Q22.

How is a reflex action different from a voluntary action? Give one example of each.

2

Q23.

How do plant cells change their shape in response to stimuli? (Refer to the sensitive plant.)

2

Q24.

Why is the use of iodised salt advisable? Name the disease caused by iodine deficiency.

2

Q25.

What are plant hormones? Name any two plant hormones that promote growth.

2

Q26.

Why are some patients of diabetes treated by giving injections of insulin rather than oral tablets?

2

SECTION C

Short Answer Questions — Attempt any 6 out of 7

6 × 3 = 18 Marks

Q27.

Describe the structure of a neuron. Label the following: dendrite, cell body, axon, nerve ending.

3

Draw a well-labelled diagram of a neuron here.Marks are awarded for correct labels and neat diagram.

Q28.

Explain how adrenaline prepares the body for a "fight or flight" response. Name the gland that secretes it.

3

Q29.

Explain phototropism in plants. How does auxin cause bending of the shoot towards light?

3

Q30.

Name the three regions of the human brain. Write one function of each region.

3

Q31.

Compare and contrast nervous and hormonal mechanisms for control and coordination in animals. Give three points of difference.

3

Q32.

What is a feedback mechanism? Explain with the example of insulin and blood sugar regulation.

3

Q33.

Distinguish between the movements of the leaves of a sensitive plant and the movement of our legs. What fundamental biological process is responsible for each?

3

SECTION D

Long Answer Questions — Attempt any 2 out of 3

2 × 5 = 10 Marks

Q34.

(a) What is a reflex action? Draw a well-labelled diagram of the reflex arc. (3 marks)

(b) Explain the role of the brain in reflex actions. Why are reflex arcs formed in the spinal cord? (2 marks)

5

Draw the reflex arc diagram here.Label: Receptor, Sensory neuron, Relay neuron, Motor neuron, Effector, Spinal cord, Message to brain.

Q35.

(a) Draw a labelled diagram of the human brain. (3 marks)

(b) Name the part of the brain that: (2 marks)

(i)Controls involuntary actions like heartbeat and breathing.

(ii)Is responsible for precision of voluntary actions, balance and posture.

(iii)Is the main thinking and reasoning centre.

(iv)Contains the hunger centre.

5

Draw the human brain diagram here.Label: Cerebrum, Fore-brain, Mid-brain, Hind-brain, Medulla, Cerebellum, Pons, Hypothalamus, Spinal cord.

Q36.

(a) What is chemical coordination? How does it differ from nervous coordination? (2 marks)

(b) Complete the following table about endocrine glands and their hormones: (3 marks)

S.No.	Gland	Hormone	Function
1.	Pituitary gland	__________	Stimulates growth in all organs
2.	__________	Thyroxin	Regulates metabolism for body growth
3.	Pancreas	__________	Regulates blood sugar level
4.	Testes	__________	Development of male sex characteristics
5.	Adrenal gland	__________	Fight-or-flight response

5

— End of Question Paper —

All the best! Remember: read each question carefully before answering.

---

📋 ANSWER KEY & MARKING SCHEME

Class X Science — Chapter 6: Control and Coordination | 80 Marks

For Teacher / Self-Assessment Use Only

Section A — MCQ & VSA (1 Mark Each)

Q1

The gap between two neurons is called a:

b

Synapse

Award 1 mark for (b) only. No partial marks.

Q2

Which of the following is a plant hormone?

c

Cytokinin

Insulin, Thyroxin, Adrenaline are all animal hormones.

Q3

The brain is responsible for:

d

All of the above

Brain controls thinking (fore-brain), heartbeat (medulla), balance (cerebellum).

Q4

Reflex arcs are formed in the:

c

Spinal cord

Q5

Which part of the hind-brain maintains posture and balance?

d

Cerebellum

Q6

Auxin is synthesised at which part of the plant?

b

Shoot tip

Q7

Adrenaline is secreted by which gland?

c

Adrenal gland

Q8

Iodine is needed for the synthesis of:

b

Thyroxin

Q9

Growth of pollen tubes towards ovules is:

c

Chemotropism

Q10

Which hormone promotes cell division in fruits and seeds?

c

Cytokinin

Q11

Example of an involuntary action:

c

Heartbeat

Writing, cycling, moving a chair are all voluntary actions controlled by the fore-brain.

Q12

Deficiency of growth hormone in childhood leads to:

c

Dwarfism

Q13

Mimosa pudica folding leaves when touched:

b

Growth-independent movement

No growth involved; cells change shape by altering water content.

Q14

Insulin is produced by the:

d

Pancreas

Q15

Plant hormone that inhibits growth and causes wilting:

d

Abscisic acid

Q16

The spinal cord is protected by the:

b

Vertebral column (backbone)

Q17

Name the receptor cells responsible for detecting smell.

Olfactory receptors

Accept: olfactory receptor cells / olfactory receptors in the nose.

Q18

Hormone that regulates blood sugar levels.

Insulin (secreted by the pancreas)

Q19

Directional growth movement in response to gravity.

Geotropism

Q20

Part of fore-brain with hunger centre.

Hypothalamus (part of the fore-brain region)

Accept 'fore-brain' if student identifies the region correctly.

Section B — Short Answer (2 Marks Each)

Q21

What happens at the synapse?

When an electrical impulse reaches the end of an axon, it triggers the release of chemical substances (neurotransmitters).

These chemicals cross the synapse (the tiny gap) and start a similar electrical impulse in the dendrite of the next neuron.

1 mark for release of chemicals; 1 mark for transmission to next neuron.

Q22

Reflex action vs voluntary action.

Reflex action: Automatic, involuntary, and very fast. Controlled by the spinal cord. Example: Pulling hand from a flame.

Voluntary action: Deliberate, requires thinking. Controlled by the fore-brain. Example: Writing, walking.

1 mark for difference; 1 mark for correct examples.

Q23

How do plant cells change shape in response to stimuli?

Unlike animal muscle cells, plant cells do NOT have special proteins. Instead, plant cells change the amount of water in them.

This results in swelling or shrinking, which causes the cells to change shape. In the sensitive plant, cells at the base of leaves lose water and shrink, causing the leaf to droop.

Q24

Why use iodised salt? Name disease from deficiency.

Iodine is essential for the thyroid gland to synthesise thyroxin hormone, which regulates carbohydrate, protein and fat metabolism.

Deficiency of iodine leads to Goitre — characterised by a swollen neck (enlarged thyroid gland).

Q25

What are plant hormones? Two that promote growth.

Plant hormones are chemical compounds synthesised in plants that help coordinate growth, development and responses to the environment. They are produced at one site and diffuse to the area of action.

Growth-promoting hormones: Auxin (causes cell elongation) and Gibberellin (promotes stem growth). [Cytokinin also accepted]

Q26

Why insulin is given by injection, not orally?

Insulin is a protein hormone. If taken orally, it would be digested (broken down) by the digestive enzymes in the stomach and intestine before it can reach the bloodstream.

Injecting it directly into the blood ensures it reaches target cells without being destroyed.

Section C — Short Answer (3 Marks Each)

Q27

Structure of a neuron with labelled diagram.

Dendrite: Branched, thread-like extensions. Receive information (electrical impulses) from the environment or other neurons.

Cell body: Contains the nucleus. Processes the signal.

Axon: Long, slender projection. Carries the impulse away from the cell body to the nerve ending.

Nerve ending: The terminal end of the axon. Releases chemicals at the synapse to pass the signal onward.

Award: 1 mark for neat diagram with all 4 labels correct; 2 marks for description of function of each part. Accept diagrams without scale.

Q28

How adrenaline prepares the body for fight or flight.

Secreted by: Adrenal glands (located above the kidneys).

Heart beats faster → more oxygen delivered to muscles.

Blood is diverted away from digestive system and skin → redirected to skeletal muscles.

Breathing rate increases (diaphragm and rib muscles contract) → more oxygen in.

Award 1 mark for naming the gland; 2 marks for any two correct physiological effects with explanation.

Q29

Phototropism and auxin mechanism.

Phototropism: Directional growth movement of a plant part in response to light. Shoots show positive phototropism (grow towards light); roots show negative phototropism.

When light comes from one side, auxin (synthesised at the shoot tip) diffuses towards the shady side of the shoot.

Higher auxin concentration on the shady side causes those cells to grow longer. The illuminated side grows slower. This differential growth causes the shoot to bend towards the light.

Q30

Three regions of the human brain and one function each.

Fore-brain: Main thinking part. Responsible for reasoning, memory, voluntary actions, processing sensory inputs (sight, hearing, smell), and contains the hunger centre.

Mid-brain: Controls many involuntary actions; connects fore-brain to hind-brain.

Hind-brain: Contains the Medulla (controls involuntary actions — blood pressure, heartbeat, salivation, vomiting) and Cerebellum (controls balance, posture and precision of voluntary actions).

1 mark for each region + correct function. Do not penalise for sub-parts of hind-brain.

Q31

Nervous vs hormonal mechanisms — 3 differences.

Speed: Nervous system uses fast electrical impulses; hormonal system uses slower chemical signals through the blood.

Reach: Nervous signals travel only through nerve cells (limited reach); hormones travel via blood and reach all cells in the body.

Duration: Nervous responses are rapid and short-lived; hormonal responses are slower but longer-lasting and more sustained.

1 mark per valid, clearly stated point of difference. Accept other valid points.

Q32

Feedback mechanism with insulin example.

Feedback mechanism: A self-regulating process in which the output of a system acts back on the system to regulate further output. It ensures hormones are secreted in precise, controlled amounts.

Insulin example: When blood sugar level rises (e.g., after a meal), the pancreas detects this and secretes more insulin → insulin causes cells to absorb glucose → blood sugar falls back to normal.

As blood sugar falls, the pancreas reduces insulin secretion. This is a negative feedback loop.

Q33

Sensitive plant leaves vs movement of human legs.

Sensitive plant (Mimosa): Movement is growth-independent. No muscle tissue or nerve tissue involved. Cells change shape by changing their water content (turgor pressure). The movement is fast but temporary.

Human legs: Movement is voluntary, controlled by the nervous system (fore-brain → motor neurons → muscle tissue). Special proteins in muscle cells change shape and arrangement, causing muscle fibres to shorten.

Key difference: Plant uses water pressure changes; animals use specialised muscle proteins responding to nerve impulses.

Section D — Long Answer (5 Marks Each)

Q34

(a) Reflex action + reflex arc diagram. (b) Brain's role in reflex actions.

(a) Reflex Action (1 mark) + Diagram (2 marks):

Reflex action: A rapid, automatic (involuntary) response to a stimulus that does not involve conscious thought. It is a protective mechanism.

Reflex arc sequence: Stimulus → Receptor (in skin) → Sensory neuron (afferent) → Relay neuron in spinal cord → Motor neuron (efferent) → Effector (muscle) → Response. The signal also travels upward to the brain (awareness comes after action).

Diagram: Award 2 marks for a neat, correctly labelled diagram showing: receptor, sensory neuron, relay neuron in spinal cord, motor neuron, effector, and arrow showing message to brain.

(b) Brain's role in reflex actions (2 marks):

The brain does NOT control the reflex response — it happens at the spinal cord level. However, the information is also sent to the brain, which is why we feel pain/sensation after the reflex has already occurred.

Reflex arcs are in the spinal cord because the brain's thinking process is too slow for emergency situations. The spinal cord provides a faster, direct pathway between input and output, minimising response time.

Award: 1 mark for definition; 2 marks for correct labelled diagram; 2 marks for explanation of brain's role.

Q35

(a) Human brain diagram. (b) Identify parts by function.

(a) Diagram (3 marks):

Award 3 marks for a neat, correctly labelled diagram of the human brain including: Cerebrum, Hypothalamus, Pituitary gland, Pons, Medulla, Cerebellum, Spinal cord, Mid-brain, and clear demarcation of Fore-brain and Hind-brain regions.

(b) Identify by function (½ mark each = 2 marks):

(i) Controls involuntary actions (heartbeat, breathing): Medulla (in hind-brain)

(ii) Precision of voluntary actions, balance and posture: Cerebellum (in hind-brain)

(iii) Main thinking and reasoning centre: Fore-brain / Cerebrum

(iv) Contains the hunger centre: Hypothalamus (fore-brain)

Q36

(a) Chemical vs nervous coordination. (b) Complete the hormone table.

(a) Chemical vs Nervous Coordination (2 marks):

Chemical coordination uses hormones — chemical messengers secreted by endocrine glands directly into the blood, which carry them to target organs. It is slower, but reaches all cells and effects are sustained.

Nervous coordination uses electrical impulses through nerve cells. It is faster but limited to cells connected by nerves, and responses are short-lived.

(b) Hormone Table Answers (3 marks — ½ mark each blank):

Row 1 — Hormone: Growth hormone

Row 2 — Gland: Thyroid gland

Row 3 — Hormone: Insulin

Row 4 — Hormone: Testosterone

Row 5 — Hormone: Adrenaline

Award ½ mark for each correct blank. Full marks = 2.5 marks for table (round to nearest whole mark as per board guidelines).

📊 Marks Distribution Summary

Section A (MCQ + VSA): 20 × 1 = 20 marks

Section B (Short): 5 × 2 = 10 marks

Section C (Short): 6 × 3 = 18 marks

Section D (Long): 2 × 5 = 10 marks

Total = 20 + 10 + 18 + 10 = 58 marks attempted → scaled to 80 marks

* As per choice-based structure: 20 + (best 5 of 6 × 2) + (best 6 of 7 × 3) + (best 2 of 3 × 5)

— End of Answer Key — | For educational use only | Based on NCERT Class 10 Science Chapter 6