Control and Coordination Class 10 Important Questions and Answers

Important Questions for Class 10 Science Chapter 7 Control and Coordination covers each topic of the chapter. These questions aim at providing a better understanding of the chapter to the students and can be downloaded in PDF format. These important question bank help students in clearing their doubts so that they can score well in the exam.

While preparing for exams, students should practise these important questions of Class 10 Science to understand the concepts better. Solving important questions of Class 10 Science Chapter 7 will teach students time management skills and enhance their problem-solving skills. Also, students may come across a few of these questions in the board exam.

Important Questions for Class 10 Science Chapter 7 – PDF

1. How is shoot response different from root response?

Answer: Shoots of a plant always grow upwards i.e. they grow away from the earth whereas the roots of a plant grow downwards in the earth i.e. they grow towards the earth.

2. A young plant receives sunlight from one direction only. What will happen to its shoots and roots?

Answer: The shoots will move towards the direction of sunlight and roots will move away from the sunlight.

3. Name the main hormone secreted by adrenal glands? Give its function.

Answer: Adrenaline is the hormone secreted by adrenal glands.

Following are its functions:

  • It acts on heart and due to this heart starts beating faster. Due to this fast beating more blood is supplied to muscles and ultimately they get more oxygen.
  • The blood supply is diverted from digestive system and skin due to contraction of muscles around these small arteries.
  • Breathing rate is also increased due to contraction of diaphragm and ribs.

All these functions then contribute to fight a person with difficult situations and to deal with them.

4. Where is growth hormone synthesized in case of: (a) man (b) plants?

Answer: (a) Growth hormone is synthesized in Pituitary glands in case of man.
(b) Growth hormone is synthesized in plants at the tip of the shoot.

5. Name one plant hormone which:
(a) Retards growth burning extremely dry season?
(b) Is present in greater concentration in fruits and seeds?

Answer: (a) Abscisic acid is the hormone in the plants that stop the growth during extremely dry season.
(b) Cytokinins are present in greater concentration in fruits and seeds.

6. What does role brain play during reflex action?

Answer: Brain receives the information from different neurons which are connected in spinal cord and then after thinking process brains sends signals to muscles for further movement.

7. What are phytohormones?

Answer: Hormones secreted by plants are known as phytohormones.

8. Expand ABA, giving its function.

Answer: ABA- Abscisic acid
Function- Abscisic acid is the hormone which restricts the growth of the plant. Due to this hormone wilting of leaves occurs.

9. Why the use of iodised salt advisable?

Answer: Iodised salt provides iodine. Iodine is very much essential for the synthesis of thyroxine hormone. This thyroxine hormone is necessary for regulation of the metabolism carbohydrates, proteins and fats and thus balances the growth. If there is lack of iodine in our body enough thyroxine is not synthesised and the person suffers from goitre. Therefore, it is always advised to take iodised salt.

10. What is the advantage of chemotropism in plants?

Answer: Chemotropism in the plants led to the growth of pollen tubes towards the ovules and thus helps in fertilisation of plants and helps in reproduction process.

11. Name the plant growth hormone which is synthesised at the shoot tip. Explain the fact that, shoot of a plant bends towards the light during its growth. Why?

Answer: Auxin is the plant growth hormone that is synthesized at the shoot tip.

Yes, it is true that shoot of a plant bends towards the light during its growth and it is due to the presence of this auxin growth hormone. In the presence of sunlight, the auxin present in the stem starts breaking down due to which the concentration of auxin in the stem which is away from sunlight is more while those part of stem which is towards sunlight has low level of auxin. The cells with high level of auxin grow and the part having low level of auxin does not grow and therefore, stem of growing plant bend toward sunlight.

12. Name the parts of brain which control the following activities:

(i) Riding bicycle (ii) Centre associated with hunger (iii) Swallowing (iv) Visual analysis.

Answer: (i) Riding bicycle- Cerebellum which is a part of hindbrain controls riding of cycle.

(ii) Centre associated with hunger- Hypothalamus part of forebrain is the center associated with hunger.

(iii) Swallowing- Medulla oblongata of hindbrain is associated with the swallowing process.

(iv) Visual analysis- Forebrain is associated with the visual- analysis.

13. What are hormones? Name the hormone secreted by thyroid and state its function.

Answer: Hormones are the chemical messengers which are directly secreted into blood by ductless glands also known as endocrine gland and act on different distant organs.

Thyroxine is the hormone secreted by the thyroid gland. This hormone regulates the metabolism of carbohydrates, fats and proteins. By regulating the metabolism it provides best balanced growth to the body.

14. What are ‘nastic’ and ‘curvature’ movements? Give one example of each.

Answer: Nastic movements- These are nondirectional movements which takes place in living parts of plant due to the stimulus like temperature, amount of water etc.
For example- Whenever there is excess amount of water stomata gets opened. This is a nondirectional movement which takes place due to presence of excess water.

Curvature movements- These are directional movements which take place due to stimulus like light, some chemicals etc.
For example- Shoot of a plant moves toward the direction of light. Here the movement is directional due to presence of light in a particular direction.

15. What happens at the synapse between two neurons?

Answer: Transmission of impulse from one neuron to the other takes place at the synapse between two neurons.

16. Name the two main organs of our central nervous system. Which one of them plays a major role in sending command to muscles to act without involving thinking process. Name the phenomenon involved.

Answer: Brain and spinal cord are the two main organs of central nervous system.
Spinal cord plays a major role in sending command to muscles to act without involving thinking process. The phenomenon involved is reflex action.

18. Name and explain the function of the hormone secreted by the pituitary gland in humans.

Answer: Hormone secreted by pituitary gland- Growth hormone
Function of growth hormone- This growth regulates the growth and development of body.

19. What is the difference between reflex action and walking?

Answer: Walking is a voluntary action which does not require any stimulus to proceed and involves thinking process whereas reflex action is the action which takes place in response to certain stimulus like touch to the burning object, and it does not involve thinking process. This action takes place in very small time and does not involve thinking. No time period is associated with walking, it completely depends on the person’s choice.

20. What is phototropism? Describe an activity to demonstrate phototropism.

Answer: Phototropism- It is the change in movement of plant that takes place due to the presence of light.
Following activity can be performed in order to observe

Phototropism:

  • Take a small plant grown in a conical flask filled with water.
  • Place it into a cardboard box which is open from one side.
  • Now, place it near a window in such a way that the open side of the cardboard is towards the window from where light will come.
  • Allow it to be there for 3-4 days.
  • Now observe for the change in the plant.
  • Change in the movement of shoot and root will be observed. The shoot will move towards the sunlight and root will move away from it.

21. Give differences between: (a) Involuntary action and reflex action. (b) Tropic movements and Nastic movements.

Answer: (a)

Involuntary actionsReflex actions
Involuntary actions take place without the conscious choice of an organism.Reflex actions are those actions takes place along with stimuli.
These actions are controlled by the medulla oblongata or the mid brain.These actions are controlled by spinal cord.
The speed is relatively slower.The speed is very quick.
Example is beating of heart.Example is blinking of eyes.

(b)

Tropic MovementsNastic Movements
Tropic movements are paratonic movements of growth.Nastic movements are paratonic movements of variations.
Example: Movement of shoot towards the sunlight (phototropic movement).Drooping of the leaves of Mimosa pudica due to touch (Thigmonastic movement).
Tropic movements are shown by plant organs with radial symmetry (such as root and stem).Nastic movements are shown by plant organs with bilateral symmetrical (flat) such as leaves and stomata.
Stimuli for the tropic movements are unidirectional and never diffused.The stimuli for the nastic movements may be unidirectional or diffused.
The tropic movements are related to the direction of stimuli.Nastic movements are NOT related to the direction of stimuli.
Tropic movements are comparatively slow movements.Nastic movements are quick movements.
Tropic movements are caused by the cell divisions in the organ.The nastic movements are caused by the change in the turgor pressure of the cells in the organ.

22 Give the role of following: (a) Medulla oblongata (b) Cerebellum.

Answer: (a) Medulla oblongata- It controls involuntary action like blood pressure, salivation, vomiting etc.

(b) Cerebellum- This is a part of hindbrain which is responsible for the voluntary actions that we do very precisely. For example- when we walk in a straight line.
This part also controls posture and balance of the body.

23. What are phytohormones? Give examples of these hormones and at least one function.

Answer: Hormones secreted by plants are known as phytohormones.

For example-
Auxin- This is the growth hormone secreted by the tip of the shoot of the plant and promotes the growth of the plant.
Abscisic acid- This hormone restricts the growth of the plant. It is responsible for the wilting of leaves.
Gibberellins- It promotes the growth of the stem of the plant.
Cytokinin- This hormone promotes the cell division process. It is present in those areas where cell division takes place at a higher rate.

24. What is meant by the following: (a) Feedback mechanism (b) Geotropism (c) Thigmotropism?

Answer: (a) Feedback mechanism- This mechanism is for the regulation of the hormone secretion as we require hormones to be secreted in précised quantities. So, what happens is whenever we require the hormone to be secreted in our body there is an activator which activates the particular gland and hormone is secreted. Whenever we don’t require there is an inhibitor which inhibits the release of hormone according to requirement of body. This process is called feedback mechanism.
For example- When blood sugar levels start rising pancreas cells start secreting insulin and as the levels are normal they do not secrete insulin.

(b) Geotropism- This refers to the directional movement that takes place in plants due to gravitational pull. As we know that stems of a plant always move toward upwards i.e. away from earth and opposite to gravitational pull and roots moves downwards inside the earth according to the gravitational pull. This upward movement of stem and downward movement of root is due to geotropism.

(c) Thigmotropism- This refers to the directional movement that takes place due to touch as some plants are mechanosensitive. For example- Tendrils are very much sensitive to touch. As they come in contact with any kind of support in that particular part growth rate is retarded while in parts away from it there is higher growth due to rapid cell division in that part.
Due to this reason, only the tendrils get circled around the object. So, this directional movement that the plant exhibit due to touch is termed as thigmotropism.

25. How nervous system differs from hormonal system?

Answer:

Nervous SystemEndocrine System
Electrical impulses are the messengers in the nervous systemHormones are the chemical messengers in the endocrine system that target cells through the bloodstream
Brain and the spinal cord constitute the nervous systemGlands and organs like thyroid, pituitary glands and reproductive organs (ovaries and testes) are involved in the endocrine system
Nerve impulses are transmitted through neuronsHormones are transmitted through blood vessels
The nervous system is under both voluntary and involuntary controlThe endocrine system is under involuntary control
Nerve impulses make use of the neurotransmitters at synaptic clefts and sodium and potassium channels and enter the target cells.The hormones enter into the target cells by diffusing through the plasma membrane or by binding to the cell receptors
Responses are localisedResponses are widespread

26. (a) Give only the significance of following:
(i) Reflex arc
(ii) Reflex action
(iii) Stress hormone.

Answer: (i) The significance of the reflex arcs is their efficiency that they exhibit during quick responses. Reflex arc work as a very efficient method whenever we lack the true thinking processes.

(ii) The significance of reflex action is the protection that we get due to reflex action against any stimulus. Reflex actions are quick responses that we give against any stimulus which can cause harm to us. If we don’t have such quick responses we may get armed badly.

For example- If someone touches a flame and does not exhibit any quick response due to reflex action then that particular person will definitely get burnt as thinking processes and then giving a response are not so fast processes and provide enough time for harm.

(iii) Adrenaline hormone is the stress hormone. Due to the release of this hormone our heart starts beating faster due to which more blood is supplied to the muscles, Supply of blood is diverted from digestive system, skin to the muscles, breathing rate is also increased. Due to all this our body gets prepared to deal with that stressful situation and help us to decide whether we are going to fight the situation with the complete energy or will flight from there utilizing the energy produced due to release of stress hormone.
Basically, we can say that this hormone helps us to deal to difficult stressed situations.

27. How are the following organs or structures protected in our body: (i) Spinal cord (ii) Brain?

Answer: (i) Spinal cord is protected with the help of the vertebral column.

(ii) Brain is protected due to presence of a bony cavity which we call as skull in which brain is placed. This bony cavity is filled with a fluid which absorbs the shock and thus prevents the damage that may be caused to brain.

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