Students should refer to Worksheets Class 10 Science Control and Coordination Chapter 7 provided below with important questions and answers. These important questions with solutions for Chapter 7 Control and Coordination have been prepared by expert teachers for Class 10 Science based on the expected pattern of questions in the class 10 exams. We have provided Worksheets for Class 10 Science for all chapters on our website. You should carefully learn all the important examinations questions provided below as they will help you to get better marks in your class tests and exams.
Control and Coordination Worksheets Class 10 Science
Question. Which of the following is a plant hormone?
Question. The gap between two neurons is called a
Question. The brain is responsible for
(b) regulating the heart beat.
(c) balancing the body.
(d) all of the above
Very Short Answer Type Questions :
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 one of the following actions on touch is an example of chemical control?
Movement of the touch-sensitive plant Movement in human leg
Answer: Movement of the touch-sensitive plant.
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. What are ‘nastic’ and ‘curvature’ movements? Give one example of each.
Answer: Nastic movements are non-directional induced variation movements that occur due to turgor changes. These are induced by external stimuli such as light, temperature, touch, etc. For example, if we touch the leaves of Mimosa pudica we find that its leaves immediately fold up and droop. This occurs due to turgor changes in cells of plant.
Curvature movements are directional movements that occur in response to external stimuli such as light, force of gravity, etc. This stimuli cause differential growth in specific plant part via action of phytohormones. For example, roots of a plant grow downward in the soil in the direction of gravity showing positive geotropism.
Question. What is reflex action? Describe the steps involved in a reflex action.
Answer: Reflex action is a spontaneous, automatic and mechanical response to a stimulus acting on a specific 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 effectors (muscles or glands) which show response. Tje path taken by nerve impulses in a reflex action is called as reflex arc.
Question. (a) Draw the structure of a neuron and label the following on it :
nucleus, dendrite, cell body and axon.
(b) Name the part of neuron :
(i) Where information is acquired
(ii) Through which information travels as an electrical impulse.
Answer: (a) : Diagrammatic representation of a neuron is as follows:
(b) (i) Dendrites or dendrons acquires the information and sets of a chemical reaction that creates an electrical impulse.
(ii) The electrical impulse travels from the dendrite to cell body and then along the axon to its nerve ending. At the end of the axon, the electrical impulse sets of the release of chemicals which cross the synapse (gap) and start a similar electrical impulse in a dendrite to the next neuron. This is a general scheme how nervous impulse travel in the body.
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.
Short Answer Type Questions :
Question. What is the role of the brain in reflex action?
Answer. Reflex actions are sudden responses, which do not involve any thinking. For example, when we touch a hot object, we withdraw our hand immediately without thinking as thinking may take time which would be enough to get us burnt.
The sensory nerves that detect the heat are connected to the nerves that move the muscles of the hand. Such a connection of detecting the signal from the nerves (input) and responding to it quickly (output) is called a reflex arc. The reflex arcs-connections present between the input and output nerves-meet in a bundle in the spinal cord.
Reflex arcs are formed in the spinal cord and the information (input) reaches the brain. The brain is only aware of the signal and the response that has taken place. However, the brain has no role to play in the creation of the response.
Question. How does chemical coordination occur in plants?
Answer. In animals, control and coordination occur with the help of nervous system. However, plants do not have a nervous system. Plants respond to stimuli by showing movements. The growth, development, and responses to the environment in plants is controlled and coordinated by a special class of chemical substances known as hormones. These hormones are produced in one part of the plant body and are translocated to other needy parts. For example, a hormone produced in roots is translocated to other parts when required. The five major types of phytohormone are auxins, gibberellins, cytokinins, abscisic acid, and ethylene. These phytohormones are either growth promoters (such as auxins, gibberellins, cytokinins, and ethylene) or growth inhibitors such as abscisic acid.
Question. What happens at the synapse between two neurons?
Answer. A very small gap that occurs between the last portion of axon of one neuron and the dendron of the other neuron is known as a synapse. It acts as a one way valve to transmit impulses in one direction only. This uni-direction transfer of impulses occurs as the chemicals are produced in only one side of the neuron i.e., the axon’s side. From axon, the impulses travel across the synapse to the dendron of the other neuron.
Question. What are plant hormones?
Answer. Plant hormones or phytohormones arenaturally’occurring organic substances. These are synthesized in one part of the plant body (in minute quantities) and are translocated to other parts when required. The five major types of phytohormones are auxins, gibberellins, cytokinins, abscisic acid, and ethylene.
Question. How is the movement of leaves of the sensitive plant different from the movement of a shoot towards light?
Answer. The movement of leaves of the sensitive plant, Mimosa pudica or “touch me not”, occurs in response to touch or contact stimuli. This movement is independent of growth. The movement of shoot towards light is known as phototropism. This type of movement is directional and is growth dependent.
Question. Give an example of a plant hormone that promotes growth.
Answer. Auxin is an example of growth’promoting plant hormone.
Question. How do auxins promote the growth of a tendril around a support?
Answer. Auxin is synthesized at the shoot tip. It helps the cell grow longer. When a tendril comes in contact with a support, auxin stimulates faster growth of the cells on the opposite side, so that the tendril forms a coil around the support. This makes the tendrils appear as a watch spring.
Question. Design an experiment to demonstrate hydrotropism.
Answer. Take two small beakers and label them as A and B. Fill beaker A with water. Now make a cylindrical ‘shaped roll from a filter paper and keep it as a bridge between beaker A and beaker B, as shown in the figure. Attach few germinating seeds in the middle of the filter paper bridge. Now, cover the entire set’up with a transparent plastic container so that the moisture is retained.
This experiment demonstrates the phenomenon of hydrotropism.
Question. How does chemical coordination take place in animals?
Answer. Chemical coordination takes place in animals with the help of hormones. Hormone is the chemical messenger that regulates the physiological processes in living organisms. It is secreted by glands. The regulation of physiological processes, and control and coordination by hormones comes under the endocrine system. The nervous system along with the endocrine system in our body controls and coordinates the physiological processes.
Question. How do we detect the smell of an agarbatti(incense stick)?
Answer. The thinking part of our brain is the forebrain. It has separate areas that are specialized for hearing, smelling, sight, taste, touch, etc. The forebrain also has regions that collect information or impulses from the various receptors. When the smell of an incense stick reaches us, our forebrain detects it. Then, the forebrain interprets it by putting it together with the information received from other receptors and also with the information already stored in the brain.
Question. What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?
Answer. Receptors are sensory structures (organs/tissues or cells) present all over the body. The receptors are either grouped in case of eye or ear, or scattered in case of skin.
Functions of receptors:
(i) They sense the external stimuli such as heat or pain.
(ii) They also trigger an impulse in the sensory neuron which sends message to the spinal cord.
When the receptors are damaged, the external stimuli transferring signals to the brain are not felt. For example, in the case of damaged receptors, if we accidentally touch any hot object, then our hands might get burnt as damaged receptors cannot perceive the external stimuli of heat and pain.
Question. Draw the structure of a neuron and explain its function.
Answer. Neurons are the functional units of the nervous system. The three main parts of a neuron are axon, dendrite, and cell body.
Functions of the three parts of a neuron:
1. Axon: It conducts messages away from the cell body.
Dendrite: It receives information from axon of another cell and conducts the messages towards the cell body.
2. Cell body: It contains nucleus, mitochondria, and other organelles. It is mainly concerned with the maintenance and growth.
Question. Which signals will get disrupted in case of a spinal cord injury?
Answer. The reflex arc connections between the input and output nerves meet in a bundle in the spinal cord. In fact, nerves from all over the body meet in a bundle in the spinal cord on their way to the brain. In case of any injury to the spinal cord, the signals coming from the nerves as well as the signals coming to the receptors will be disrupted.
Question. Which part of the brain maintains posture and equilibrium of the body?
Answer. Cerebellum, a part of hindbrain is responsible for maintaining posture and equilibrium of the body.
Question. What is the need for a system of control and coordination in an organism?
Answer. The maintenance of the body functions in response to changes in the body by working together of various integrated body systems is known as coordination. All the movements that occur in response to stimuli are carefully coordinated and controlled. In animals, the control and coordination movements are provided by nervous and muscular systems. The nervous system sends messages to and away from the brain. The spinal cord plays an important role in the relay of messages. In the absence of this system of control and coordination, our body will not be able to function properly. For example, when we accidentally touch a hot utensil, we immediately withdraw our hand. In the absence of nerve transmission, we will not withdraw our hand and may get burnt.
Question. How are involuntary actions and reflex actions different from each other?
Answer. Involuntary actions cannot be consciously controlled. For example, we cannot consciously control the movement of food in the alimentary canal. These actions are however directly under the control of the brain. On the other hand, the reflex actions such as closing of eyes immediately when bright light is focused show sudden response and do not involve any thinking. This means that unlike involuntary actions, the reflex actions are not under the control of brain.
Question. Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.
Question. What are the changes seen in girls at the time of puberty?
Answer. Secondary sexual characteristics in girls:
1. Increase in breast size and darkening of skin of the nipples present at the tips of the breasts.
2. Appearance of hair in the genital area.
3. Appearance of hair in other areas of skin like underarms, face, hands, and legs.
4. Increase in the size of uterus and ovary.
5. Beginning of menstrual cycle.
6. More secretion of oil from the skin, which results in the appearance of pimples.
Question. Why are some patients of diabetes treated by giving injections of insulin?
Answer. Diabetes is a disease in which the level of sugar in the blood is too high. Insulin, a hormone secreted by the pancreas, helps in regulating the blood sugar levels. This is the reason why diabetic patients are treated by giving injections of insulin.
Question. What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs?
Question. How does our body respond when adrenaline is secreted into the blood?
Answer. Adrenalin is a hormone secreted by the adrenal glands in case of any danger or emergency or any kinds of stress. It is secreted directly into the blood and is transported to different parts of the body. When secreted in large amounts, it speeds up the heartbeat and hence supplies more oxygen to the muscles. The breathing rate also increases due to contractions of diaphragm and rib muscles. It also increases the blood pressure. All these responses enable the body to deal with any stress or emergency.
Question. Why is the use of iodised salt advisable?
Answer. Iodine stimulates the thyroid gland to produce thyroxin hormone. It regulates carbohydrate, fat, and protein metabolism in our body. Deficiency of this hormone results in the enlargement of the thyroid gland. This can lead to goitre, a disease characterized by swollen neck. Therefore, iodised salt is advised for normal functioning of the thyroid gland.
Long Answer Type Questions :
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) (i) For definition of phototroprism and its activity refer to answer 9.
(ii) 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 conforms 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 differentiation 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 floower and fruits.
(III) It promotes falling and senescence in leaves.
(IV) It promotes closing of stomata and thus affects transpiration and wilting in leaves.
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 are hormones? Name the hormone secreted by thyroid and state its function.
Answer: Hormones are the chemical substances secreted by endocrine glands. They regulate biological processes in living organisms. Thyroid gland secrete three hormones : thyroxine (T4), tri-iodothyronine (T3) and calcitonin.
Both thyroxine and tri-iodothyronine are iodinated forms of the amino acid tyrosine. These two hormones have four functions:
(i) They maintain the basal metabolic rate (BMR) of the body by regulating the rate of oxidation of carbohydrates, fats and proteins and production of energy in our body.
(ii) They promote growth of body tissues and development of mental faculties.
(iii) They stimulate tissue differentiation therefore, they affect metamorphosis of a tadpole into an adult frog.
(iv) As they increase heat production, thus they maintain body temperature.
Calcitonin regulates the concentration of calcium and phosphorus in the blood.
Question. What is ‘phototropism’? How does it occur in plants? Describe an activity to demonstrate phototropism.
Answer: 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).
Question. What is the difference between a reflex action and walking?
Answer. A reflex action is a rapid, automatic response to a stimulus. It does not involve any thinking. For example, we close our eyes immediately when the bright light is focused . Walking, on the other hand, is a voluntary action. It is under our conscious control.