Please refer to Chapter 7 Control and Coordination Class 10 Science Important Questions with solutions provided below. These questions and answers have been provided for Class 10 Science based on the latest syllabus and examination guidelines issued by CBSE, NCERT, and KVS. Students should learn these problem solutions as it will help them to gain more marks in examinations. We have provided Important Questions for Class 10 Science for all chapters in your book. These Board exam questions have been designed by expert teachers of Standard 10.
Class 10 Science Important Questions Control and Coordination Chapter 7
Very Short Answer:
Question. At the time of puberty, both boys and girls show lots of changes in appearance. Name the hormones responsible for these changes.
Answer : Testosterone in male and oestrogen in females.
Question. What will happen to a plant shoot if sunlight falls on it from one direction only? What do you call this movement?
Answer : Shoot will bend towards light. Phototropism.
Question. Which mechanism control timing and amount of hormone released?
Answer : Feedback mechanism.
Question. Name two tissues that provide control and coordination in multicellular animals.
Answer : (i) Nervous tissue (ii) Endocrine tissue.
Question. What are hormones?
Answer : Hormones are the chemical substances secreted in trace amounts by specialised tissue called endocrine glands.
Question. How is spinal cord protected?
Answer : Vertebral column made by vertebrae protects the spinal cord.
Question. Write two differences between the response of the plants and response of the animals to stimuli?
|1.||No specific or specialized tissue present for conduction of information.||Specialised|
tissues are present in the body for conduction of information.
|2.||Plant cells change shape by changing the|
amount of water in them.
|Specialised proteins are found in muscle|
cells which help in changing the shape.
Question. What is meant by hydrotropism? Give an example.
Answer : The response of a plant towards water is called hydrotropism. The roots of plants show positive hydrotropism.
Question. Trace the sequences of events through a reflex arc which occur when a bright light is focused on your eyes.
Question. How does feedback mechanism regulate the hormone secretion?
Answer : The feedback mechanism regulates the timing and amount of hormone to be secreted, e.g., if a person has more sugar in his blood, this is detected by the cells of the pancreas. As a result, more insulin will be secreted to oxidise the sugar. In a reverse situation, the secretion of insulin will be reduced.
Question. Define phototropism and give one example.
Answer : Movement of plant parts towards the light is called phototropism, e.g., stem of plant usually move towards light.
Question. (a) Name one gustatory receptor and one olfactory receptor present in human beings.
(b) Write a and b in the given flow chart of neuron through which information travels as an electrical impulse.
(a) Tongue / Nose.
(b) a →Cell body, b → axon
Question. Define neuron. Name the parts of the neuron where:
a. information is acquired.
b. impulse must be converted into a chemical signal for onward transmission?
Answer : Neuron is a functional and structural unit of nervous system. These cells are specialised for conducting information via electrical impulses from one part of the body to another.
(a) dendrites (b) end of axon.
Question. Tendrils encircle or coil around the object in contact with it. Elaborate.
Answer : Tendrils are sensitive to touch. When they come in contact with any support, the part of the tendril in contact with the object does not grow as rapidly as the part of the tendril away from the object. This causes the tendril to circle around the object and thus, cling to it.
Question: Name two tissues that provide control and coordination in multicellular animals.
Answer: In multicellular animals, control and coordination, takes place through two types of tissues i.e., nervous tissue and muscular tissue.
Question: Which endocrine gland secretes the growth hormone?
Answer: Growth hormone (GH) also called somatotropin, is a peptide hormone secreted by anterior lobe of the pituitary gland.
Question: Name the two types of tropism.
Answer: The two types of tropism are phototropism and geotropism.
Question: How is the spinal cord protected in the human body?
Answer: In the human body, spinal cord is enclosed within bony cage called the vertebral column which protects it from injury.
Question: Design an experiment to demonstrate that the roots bend in the direction of water stimulus.
Answer: The given experiment demonstrates the response of roots in the direction of water stimulus. Take two glass troughs A and B and Fill each one of them two-third with soil. In trough A, plant a tiny seedling and water it daily whereas in trough B, plant a similar seedling and also place a small ‘clay pot’ inside the soil. Do not water the soil (in trough B) but put some water in the clay pot and bury it in the soil and leave it for a few days.
Now, dig up the soil carefully from both the troughs without damaging the roots of seedlings.
Result : The roots of seedling in trough A will be straight because it gets water from all sides as soil is watered uniformly. On the other hand, the roots of seedling in trough B will be bent towards the right side because roots get water oozing out from the clay pot which is kept on the right side. This experiment proves that the roots of a plant grow towards water i.e., positively hydrotropic.
Question: What is reflex action? Describe the steps involved in a refiex action.
Answer: Reflex action is a spontaneous, automatic and mechanical response to a stimulus acting on a specic receptor without the will of the animal.
In reflex action, fine tips (dendrites) of receptors (sensory neurons) quickly relay a message (electric impulse) via sensory nerves to the spinal cord. the spinal cord then sends information (impulse) via motor nerves to eectors (muscles or glands) which show response. The path taken by nerve impulses in a reflex action is called as reflex arc.
Question: (a) What is (i) phototropism and (ii) geotropism? With labelled diagrams describe an activity to show that light and gravity change the direction that plant parts grow in.
(b) Mention the role of each of the following plant hormones:
(i) Auxin (ii) Abscisic acid
Answer: (a)Phototropism is the directional movement or orientation of the plant part in response to light stimulus. If the plant part moves towards light, it is called positive phototropism. Alternatively, if the plant part moves away from light, it is called negative phototropism. For example, (i) Stem or shoot of a growing plant moves towards light and
thus shows positive phototropism. (ii) Roots of a plant move away from light thus show negative phototropism. Phototropic movement in plant is caused due to the action of auxin hormone. Phototropism can be demonstrated by the following activity.
Take two potted plants and place one plant in the open so that it receives the sunlight coming from above. On the other hand, place the other plant in a room near the window in such a way that it receives sunlight from one side, i.e., through the window. After some days, observe both the plants.
You will notice that the first plant (A) (which was kept in the open) has grown up straight towards light. However, the second plant (B) (which was kept in the room and receiving light from one side) has grown by bending towards the light. Thus, we can conclude from this experiment that the stem of plant responds to light by showing growth
movement towards light (positive phototropism).
(b) Geotropism is the directional movement or orientation of the plant part in response to gravity. If the plant part moves in the direction of gravity, it is called positive geotropism. Alternatively, if the plant part moves against the direction of gravity, it is termed as negative geotropism. For example. Roots of a plant move downward in the soil (in the direction of gravity) showing positive geotropism whereas the stem of a plant shows movement against the direction of gravity and thus showing negative geotropism.The given activity demonstrates geotropism:
Take a potted plant growing in a transparent glass jar. Keep the potted plant growing in a transparent glass jar straight on the ground. Observe that its stem is growing upward and its roots are growing downward. (Fig. A). Now place this potted plant horizontally on its side on the ground and observe the position of the growing stem and the root. Keep the plant in this position for a few days.
After few days, you will observe that when the potted plant is kept horizontally on its side on the ground, the growing stem and the growing root are parallel to the ground (Fig. B). After few days, you will find that the stem of this plant has bended upward away from earth (negative geotropism) and the root of the plant has bended downward towards earth, (positive geotropism Fig. C). This experiment confirms response of plants towards gravity (geotropism).
(b) (i) Auxin is a phytohormone which is basically growth promoter. It plays many important roles such as :
(I) Promotes cell enlargement and cell difierentiation in plants.
(II) These induces tropism.
(III) Induces parthenocarpy, i.e., formation of seedless fruits without fertilisation, in number of plants.
(IV) Auxin promotes apical dominance, a phenomenon in which presence of apical bud does not allow nearby lateral buds to grow.This is because apical bud inhibits the growth of lateral buds by releasing auxins.
(ii) Abscisic acid is a phytohormone which is basically growth inhibitor. It is also called stress hormone because its production is stimulated by drought, water logging and other adverse conditions. It performs the following functions:
(I) It promotes dormancy in seeds and buds and thus inhibits growth.
(II) It promotes abscision of flower and fruits.
(III) It promotes falling and senescence in leaves.
(IV) It promotes closing of stomata and thus afiects transpiration and wilting in leaves.
Question. a. Name the part of brain which controls
(1) voluntary action,
(2) involuntary action.
b. What is the significance of the peripheral nervous system? Name the components of this nervous system and distinguish between the origin of the two.
a. (1) Voluntary actions – cerebellum;
(2) Involuntary action — medulla oblongata.
b. The communication between the central nervous system and the other parts of the body is facilitated by the peripheral nervous system. Cranial nerves arise from the brain; spinal nerves arise from the spinal cord.
Question. How does chemical coordination occur in plants?
Explain with the help of three examples.
Answer : In plants, chemical coordination occurs through various phytohormones.
a. Auxins secreted by growing tissues. They provide growth of plants.
b. Gibberelins cause stem elongation, seed germination and flowering.
c. Cytokinins present in areas of actively dividing cells like fruits, seeds. Promote cell division.
d. Abscisic acid inhibits growth and respond to environmental stress.
Question. Illustrate with the help of a diagram, the effect of auxins in different parts of a plant.
Question. a. Name the diseases by which a person is likely to suffer due to the deficiency of: (i) iodine (ii) insulin
b. How the timing of secretion and amount of hormone secretion are regulated in human system.
Explain with example.
a. (i) Goitre (ii) Diabetes.
b. The timing and amount of hormone released are regulated by feedback mechanisms, e.g., if the sugar levels in blood rise, they are detected by the cells of the pancreas which respond by producing more insulin. As the blood sugar level falls, insulin secretion is reduced.
Question. a. Differentiate between sensory neurons and motor neurons.
b. How is brain protected in our body? Name the part of the brain responsible for precision of voluntary actions and maintaining body posture and balance of the body.
a. Sensory neurons carry impulses from receptors to brain. Motor neurons carry impulses from brain to effectors.
b. The brain is kept inside a bony box (skull). Inside the box, the brain is contained in a fluid-filled balloon which provides further shock absorption.
This fluid is known as Cerebrospinal Fluid (CSF).
Question. (a) What is reflex arc?
(b) What are the components of reflex arc?
(c) How do muscle cells move?
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.
Question. a. Give the functions of cerebellum (any two).
b. Name the components of central nervous system.
a. (i) Cerebellum is responsible for precision of voluntary action.
(ii) It maintains the posture and balance of the body.
b. The components of central nervous system are: (i) Brain (ii) Spinal cord.
Question. a. Identify the phytohormone used by plants while performing the following functions:
1. Cell division in shoot tip.
2. Inhibiting growth on approach of unfavourable conditions.
b. List in tabular form two differences between the movement in ‘touch me not’ plant and movement of shoot towards light.
a. (1) Auxin, (2) Abscisic acid.
|Movement of shoot towards light|
|Movement in “Touchme not’ plant (Nastic |
|1.||It is slow response towards any stimulus.||It is an immediate response towards a stimulus.|
|2.||It is directional.||It is non-directional.|
|3.||It is growth dependent.||It is growth independent.|
Question. What are hormones? Name the hormone produced by thyroid gland and state its function.
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.