Please refer to Control And Coordination Class 10 Science Exam Questions provided below. These questions and answers for Class 10 Science have been designed based on the past trend of questions and important topics in your class 10 Science books. You should go through all Class 10 Science Important Questions provided by our teachers which will help you to get more marks in upcoming exams.
Class 10 Science Exam Questions Control And Coordination
Class 10 Science students should read and understand the important questions and answers provided below for Control And Coordination which will help them to understand all important and difficult topics.
Very Short Answer:
Question. List two different functions performed by pancreas in our body.
Answer : (a) Pancreas makes two hormones i.e., insulin and glycogen that regulates blood sugar level.
(b) It secretes pancreatic juice that aids in the digestion of food.
Question. What are parthenocarpic fruits ?
Answer : Fruits that are not produced by fertilisation process and are seedless are called parthenocarpic fruits.
Question. Which part of the brain maintains posture and equilibrium of the body ?
Answer : Cerebellum of the hind brain maintains posture and equilibrium of the body.
Question. What do you mean by reflex action ?
Answer : Reflex action is an automatic, quick and involuntary action in the body brought about by a stimulus.
Question. Why Mimosa pudica leaves dropped down when touched ?
Answer : Due to changes in turgour pressure when we touch the leaves of Mimosa pudica plant leaves dropped down. The stimulus of touch leads to loss of turgour at the base of leaflets and petioles leading to drooping down of leaves.
Question. Give an example of plant hormone that promotes growth ?
Answer : Auxin is a plant hormone that promotes growth.
Question. What will happen if a ripened fruit is kept in a basket of raw fruits ?
Answer : If a ripened fruit is kept in a basket of raw fruits it will help in ripening of other raw fruits as the ripened fruit contains enthylene hormone which is responsible for ripening of fruits.
Question. Why are the electrochemical signals not an efficient means of communication in plants ?
Answer : Plants do not have nervous system i.e., specialised tissues like neurons as in case of animals nor do they have endocrine system to carry electrochemical signals. So, it is not an efficient means of communication in plants.
Question. Pancreas and gonads perform dual functions. Give reasons to justify the statement.
Answer : Pancreas secretes hormones as well as various digestive enzymes i.e., they are associated with both digestive and endocrine system. Similarly, gonads produce male and female gametes along with male and female sex hormones i.e., they are associated with both reproductive and endocrine system. Hence, we can say pancreas and gonads perform dual functions.
Question. Which signals will get disrupted in case of a spinal cord injury ?
Answer : Spinal cord controls mainly the reflex actions. So reflex actions and involuntary actions will get disrupted.
Question. What is geotropism ? Draw a labelled diagram of a potted plant showing positive geotropism and negative geotropism.
Answer : The upward growth of shoots and downward growth of roots in response to the pull of earth’s gravity is called geotropism.
Question. Why are some patients of diabetes treated by giving injections of insulin ?
Answer : Insulin is secreted by beta cells of Islets of Langerhans of pancreas. They convert excess glucose to glycogen stored in liver thus lowering glucose level in the blood. In diabetes patients, the sufficient amount of insulin is not secreted by pancreas so they have high sugar level in their blood. To control the sugar level they are treated by giving insulin injections.
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,
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 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.
Afer 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). Afer 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.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.
Short Answer:
Question: When our finger gets pricked by a sharp nail, we immediately take away our finger. Explain the pathway from stimulus to response ?
Answer : When our finger gets pricked by the sharp iron nail the finger receives the stimuli. It acts as a receptor organ. The sensory neuron carries the impulse from finger to the spinal cord [Central nervous system]. The spinal cord interpretes these impulses and generates motor impulse. These impulses are carried by motor neuron to the effector organ. By receiving the motor impulses immediately we take away our finger from the nail. This whole phenomenon is called reflex action and the path of impulse from Receptor → Sensory neuron → Spinal cord → Motor neuron → Effector is called reflex arc.
Question: What is feedback mechanism of hormonic regulation. Take the example of insulin to explain this phenomenon.
Answer : It is the mechanism by which the amount of any chemical increases or decreases resulting in secretion of the related hormone control of many cell activities, so they are very important for homeostasis most hormones are regulated by feedback mechanisms. A feedback mechanism is a loop in which a product feeds back to control its own production. Most hormone feedback mechanism involves negative feedback loops. Negative feedback keeps the concentration of a hormone within a narrow range.
For example,
The control of blood sugar by insulin is an example of a negative feedback mechanism. When blood sugar rises, receptors in a body sense a change. In turn the control center secretes insulin into the blood effectively lowering the blood sugar level.
Question: Name the endocrine gland which secretes growth hormone. What will be the effect of the following on a person :
(a) Deficiency of growth hormone
(b) Excess secretion of growth hormone
Answer : Pituitary gland secretes growth hormone.
(a) Deficiency of growth hormone causes dwarfism.
(b) Excess secretion of growth hormone causes gigantism.
Question: Nervous and hormonal systems together perform the function of control and coordination in human beings, Justify this statement with the help of an example.
Answer : The nervous system controls and coordinates all the functions in the body. It carries out its function in close coordination with hormonal system. Nerves don’t reach every hook and corner of body, hence needs assistance from hormones to control all the parts of body. Nervous control is faster. Hormonal control is slower. Hormonal control is based on feedback mechanism and tells body to pace up or slow down. Nervous control is on the other hand, a direct control.
Example : In situation of iodine deficiency hypothalamus releases hormones to stimulate pituitary gland it further sends stimulating hormone to thyroid gland to secrete thyroxine that regulates carbohydrate metabolism.
Question: What happens at the synapse between two neurons ?
Answer : Synapse is a point of contact between the axon terminals of one neuron with the dendrite of another neuron. The terminals of axon are swollen which contains a chemical called acetylcholine which is a neurotransmitter, which induces impulses in the dendrites of next neuron.
Synapse acts as one way valve which prevents the back flow of impulses from axon terminals. So, impulse moves from dendrites through cyton to axon. It allows the nerve impulses in one direction.
Question: What are plant hormones ? Name the plant hormones responsible for the following :
(a) Growth of stem
(b) Promotion of cell division
(c) Inhibition of growth
(d) Elongation of cells
Answer : In plants, growth, development and response to the environment are controlled and co-ordinated by a special class of chemical substances known as phytohormones. They are synthesised in minute amounts.
(a) Gibberellins (b) Cytokinins
(c) Abscisic acid (d) Auxins
Question: What is the role of brain in reflex action ?
Answer : Reflex actions are mainly controlled by spinal cord. For quick response to the stimulus spinal cord is generally involved but the information also reaches the brain where the thinking process occurs. Brain does not play any role for quick response to reflex action. But some reflex actions are only controlled by brain called cerebral reflexes like salivation at the sight of tempted food.
Question: Draw the structure of a neuron and explain its functions ?
Answer : Neuron or nerve cell is the structural and functional unit of nervous system. The three parts of the neuron are cyto or cell body, dendrites and axon.
(a) Dendrites are fine, branched cytoplasmic projections of cyton which are the site of receiving information and they conduct these impulses to cyton.
(b) Cyton receives impulses from dendrites and passes through axon. Cyton contains nucleus, nissl’s granules and other cell organelles.
(c) Axon is a long process from cyton which is surrounded by an insulating sheath called myelin sheath. Axon conducts nerve impulses away from cyton. The terminals of axon are swollen which contains chemicals called neurotransmitters. This chemical sends a new impulse in the dendrites of adjacent neurons.
Question: What is the need for a system of control and coordination in an organism ?
Answer : Multicellular organisms are highly complex. Every activity need to be regulated so that the activities can occur in proper time and correct sequence. Various organs and parts of the body should work together in a coordinate manner to perform a particular function. For proper control and coordination in higher organisms both nervous and endocrine system plays a major role.
For example : While riding a bicycle there should be proper coordination between our hands and handle of our cycle.
Question:
The above figure represents certain phenomenon pertaining to the nervous system.
(a) What does the figure represents ?
(b) Name the parts labelled a, b, c, d and e.
(c) Give the function of parts labeled a, b, d.
Answer : (a) The figure represents reflex arc.
(b) a – Receptor, b – Sensory neuron, c – Spinal cord, d – Motor neuron and e – Effector.
(c) Receptor is a group of cells or organ that receives the stimuli and converts it to an impulse.
Sensory neuron carries the impulses from receptors to the central nervous system i.e., brain or spinal cord. Motor neuron carries impulses from central nervous system to the effector organs.
Question: What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs ?
Answer :
Question: During a street fight between two individuals, mention the effects on the following organs by the autonomic nervous system, in the table given below :
Answer:
Question: What is the difference between a reflex action and walking ?
Answer :
Question: Different parts of brain are associated with specific functions. Name the part of human brain which perform the following functions :
(a) Sensation of feeling full
(b) Vomiting
(c) Picking up a pencil
(d) Riding a bicycle
Answer : (a) Forebrain
(b) Medulla or Hind Brain
(c) Cerebellum or Hind Brain
(d) Cerebellum or Hind Brain
Question: Define “hormones”. Name the hormone secreted by thyroid. Write 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 di erentiation therefore, they a ect 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. Aer 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).
Long Answer:
Question: What is hydrotropism ? Design an experiment to demonstrate this phenomenon.
Answer : The movement of root of plants towards water is called hydrotropism. Take two glass troughs A and B fill each one of them two-thirds with soil. In trough A plant a tiny seedling figure (a). In trough B plant a similar seedling and also place a small ‘clay pot’ inside the soil figure (b). Water the soil in trough A daily and uniformly. Do not water the soil in trough B but put some water in the clay pot buried in the soil. Leave both the troughs for a few days.
Now, dig up the seedlings carefully from both the trough without damaging their roots. We will find that the root of seedling in trough A is straight. On the other hand, the root of seedling in trough B is found to be bent to the right side (towards the clay pot containing water) figure (b). This can be explained as follows.
In trough A, the root of seedling gets water from both sides (because the soil is watered uniformly) in trough B, the roots gets water oozing out from the clay pot which is kept on the right side. So, the root of seedling in trough B grows and bends towards the source of water to the right side. The experiment shows that the root of a plant grows towards water. In other words, the root of a plant is positively hydrotropic.
Question: (a) Why is the use of iodised salt advisable ? Name the disease caused due to deficiency of iodine in our diet and state its one symptom.
(b) How do nerve impulses travel in the body ? Explain.
Answer : (a) Iodised salt is advisable because iodine is necessary for the formation of thyroxine hormone by thyroid gland. Goitre is the disease caused due to its deficiency.
Symptom : The neck of the person appears to be swollen due to the enlargement of thyroid gland.
(b) Two neurons are not joined to one another completely. There is a small gap between a pair of neuron. This gap is called synapse. The nerve impulse are carried out to this gap by the help of neuro transmitter (chemical substance). The conduction of nerve impulse through the synapse takes place in the form of electrical nerve impulse.
When a stimulus acts on the receptor, an electrical impulse is produced with the help of chemical reaction. This electrical impulse passes through the synapse and then to the other neuron. Thus, in this way nerve impulses travel in the body.
Question: What are the major parts of the brain ? Mention the function of different parts ?
Answer : (a) Forebrain : It comprises of cerebrum and diencephalon.
(i) Cerebrum is the seat of intelligence, memory, will power, consciousness. It controls voluntary actions. It is the largest portion of the brain. It is divided into two halves called cerebral hemispheres which are connected by a sheet of fibres called corpus callosum.
(ii) Diencephalon consists of thalamus and hypothalamus. The centre of hunger, thirst is located in hypothalamus. Hypothalamus controls body temperature and pituitary gland. Thalamus relays pain and pressure impulses to the cerebrum.
(b) Midbrain is a small tubulare part which controls reflexes involving eyes and ears.
(c) Hindbrain comprises of cerebellum, pons, medulla oblongata.
(i) Cerebellum controls and coordinates muscluar activity and maintains the posture and balance of the body.
(ii) Pons regulate rate of respiration and body heat.
(iii) Medulla oblongata controls functioning of internal organs and involuntary actions like beating of heart, breathing movement, peristals movement etc.
Question: What are reflex actions ? GIve examples ? Explain reflex are by an example with labelled diagram ?
Answer : Reflex action is a quick, automatic, involuntary, unconscious response in the body brough about by a stimulus. Examples of reflex action :
(a) Withdrawal of hand suddenly on touching a hot plat.
(b) Withdrawal of finger suddenly when pricked by a thorn.
(c) Shivering of the body on feeling cold.
(d) Sudden closure of the eyelids when bright light falls on the eye.
Reflex arc : It is the shortest route taken by impulse from receptor to effector
Example : When we touch a hot plate by our finger, we instantly withdraw our hand. Here stiimulus is touching a hot plate, receptors are our fingers. The specialiser epithelial cells of our fingers respond to stimulus and convert into impulse. The impulse is carried by sensory neuron to spinal cord which generates a motor impulse.
This impulse is carried by motor neuron to effector organ i.e., muscles of hand. Response is withdrawal of our hand.
Question: Explain the difference between nastic movements and tropic movements in plants ?
Answer :
Question: Name various plant hormones. Give their physiological effects on plant growth and development ?
Answer :
Question: How is the movement of leaves of the sensitive plant different from the movement of shoot towards light ?
Answer :
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 off 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 off 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.
