Home › Free notes › Class 10 Science › Control and Coordination

Control and Coordination – Class 10 Science notes, important questions and MCQs

NCERT Class 10 Science, chapter 6. Notes, key terms, important questions with answers and MCQs.

हिंदी में पढ़ें

Chapter overview

Animals coordinate body activities through the nervous system and hormones; plants use hormones and growth movements.

Nervous system

Neuron: dendrite → cell body → axon → nerve ending; signals cross a synapse chemically.
Reflex action: quick automatic response through the spinal cord (reflex arc).
Brain: forebrain (thinking, senses), midbrain, hindbrain (cerebellum for balance; medulla for involuntary actions like heartbeat).

Hormones in humans

Thyroxine (thyroid, needs iodine) controls metabolism; lack causes goitre.
Insulin (pancreas) lowers blood sugar; lack causes diabetes.
Adrenaline (adrenal gland) prepares the body for emergency; growth hormone (pituitary) controls growth.

Plants

Tropisms: phototropism (towards light), geotropism (roots towards gravity), hydrotropism, chemotropism.
Plant hormones: auxin (growth, bending to light), gibberellin (stem growth), cytokinin (cell division), abscisic acid (inhibits growth, wilting).
Touch-me-not (Mimosa) folds leaves on touch without growth.

Key terms

Synapse: gap between two neurons where signals pass chemically
Reflex arc: pathway of a reflex: receptor → sensory neuron → spinal cord → motor neuron → effector
Tropism: directional growth of a plant part in response to a stimulus

Formulas

Pituitary is called the master gland
Iodine is needed to make thyroxine

Important questions with answers

What is the function of the cerebellum?2 marks

The cerebellum maintains posture and balance and coordinates precise voluntary movements such as walking in a straight line or picking up a pencil.

What is a reflex arc? Draw its pathway in words.3 marks

A reflex arc is the pathway of a reflex action. Receptor (e.g. skin) → sensory neuron → relay neuron in the spinal cord → motor neuron → effector muscle. The response is quick because the signal does not have to go to the brain first.

Name the plant hormones and their functions, and explain phototropism.5 marks

Auxins promote cell elongation and growth at the shoot tip; gibberellins promote stem growth; cytokinins promote cell division (high in fruits and seeds); abscisic acid inhibits growth and causes wilting and fall of leaves. Phototropism is growth towards light. When light falls from one side, auxin moves to the shaded side of the shoot, those cells elongate more, and the shoot bends towards the light.

Quick revision

Cerebellum = balance; medulla = involuntary actions.
Insulin lowers blood sugar.
Abscisic acid is a growth inhibitor.

Exam tips

Reflexes are controlled by the spinal cord, not the brain.
Auxin collects on the shaded side, making that side grow faster — so the stem bends towards light.

Practice MCQs

The gap between two neurons is called
1. axon
2. synapse
3. dendrite
4. nerve
Show answer
Answer: (b) synapse. Synapse.
Which hormone lowers blood sugar?
1. adrenaline
2. thyroxine
3. insulin
4. estrogen
Show answer
Answer: (c) insulin. Insulin from the pancreas.
Iodine deficiency causes
1. diabetes
2. dwarfism
3. goitre
4. night blindness
Show answer
Answer: (c) goitre. Thyroid swells without iodine.
Balance and posture are maintained by the
1. cerebrum
2. hypothalamus
3. medulla
4. cerebellum
Show answer
Answer: (d) cerebellum. Cerebellum.
Bending of a shoot towards light is called
1. geotropism
2. hydrotropism
3. phototropism
4. chemotropism
Show answer
Answer: (c) phototropism. Response to light.
Which plant hormone inhibits growth?
1. auxin
2. gibberellin
3. abscisic acid
4. cytokinin
Show answer
Answer: (c) abscisic acid. Abscisic acid.
Withdrawing your hand from a hot object is controlled by the
1. cerebrum
2. pituitary
3. cerebellum
4. spinal cord
Show answer
Answer: (d) spinal cord. It is a reflex action.
Growth of the pollen tube towards the ovule is an example of
1. chemotropism
2. phototropism
3. geotropism
4. thigmotropism
Show answer
Answer: (a) chemotropism. Response to chemicals.

All chapters of Class 10 Science

Written by Kundali IQ from standard, well-established facts to help with revision. This is not an official NCERT publication; always read your textbook too.