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Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination

Previous Year Questions 2024

Q1: In a nerve cell, the site where the electrical impulse is converted into a chemical signal is known as:  (2024)
(a)
Axon
(b) Dendrites
(c) Neuromuscular junction
(d) Cell body

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (c)
This is the place where the electrical impulse traveling along a nerve cell is converted into a chemical signal to communicate with a muscle cell. At this junction, neurotransmitters are released, allowing the nerve cell to signal the muscle to contract.


Q2: (A) How is the movement of leaves of a sensitive plant different from the downward movement of the roots?  (2024)
OR
(B) There is a hormone which regulates carbohydrate, protein and fat metabolism in our body. Name the hormone and the gland which secretes it. Why is it important for us to have iodised salt in our diet?

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (A) 
Class 10 Science Chapter 6 Previous Year Questions - Control and CoordinationOR
(B)

  • Thyroxine 
  • Thyroid gland  
  • Iodine is necessary for thyroid gland to make thyroxine hormone. Deficiency of iodine in our diet causes goitre.


Q3: Define reflex action. With the help of a flow chart show the path of a reflex action such as sneezing.  (2024)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Reflex action is a sudden/spontaneous/immediate action in response to the environment/stimulus e.g. sneezing.
Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination


Q4: Select out of the following a gland which does NOT occur as a pair in the human body :  (2024)
(a) 
Pituitary    
(b) Ovary
(c) Testis    
(d) Adrenal

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a)
The pituitary gland is a single gland located at the base of the brain and is often referred to as the "master gland" because it controls many other hormone glands in the body. In contrast, the ovaries, testis, and adrenal glands occur in pairs (one on each side of the body).


Q5: (a) (i) Distinguish between hormonal co-ordination in plants and animals. (2024)
(ii) Which part of the brain is responsible for —
(1) intelligence
(2) riding a bicycle
(3) vomiting
(4) controlling hunger
(iii) How is brain and spinal-cord protected against mechanical injuries ?
OR
(b) (i) What are tropic movements ? Give an example of a plant hormone which (1) inhibits growth and (2) promotes cell division.
(ii) Explain directional movement of a tendril in pea plant in response to touch. Name the hormone responsible for this movement.

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (i)
Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination

(ii) (1) Cerebrum/forebrain,
(2) cerebellum/hindbrain
(3) medulla/ hindbrain
(4) hypothalamus/forebrain.
(iii) Brain – Bony box/skull/cranium/fluid filled balloon in skull, Spinal cord – Backbone/Vertebral column.
OR
(b) (i) Plant growth movements in response to stimuli in a particular direction/directional movements due to light, gravity etc.
(1) Plant growth inhibitor: Abscisic Acid
(2) Promotes cell division: Cytokinins
(ii)  When the tendrils come in contact with any support, auxins move away from the point of contact of the support. More growth occurs on the side away from the support. As a result, unequal growth occurs on its two sides and thus tendrils coil/ circle around the support.
Auxins


Q6: Select from the following a plant hormone which promotes cell division.  (CBSE 2024)
(a) 
Gibberellins
(b) Auxins
(c) Abscissic Acid
(d) Cytokinins

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (d)
Cytokinins are a type of plant hormone that promote cell division and growth in plants. They help stimulate the growth of shoots and leaves and play a crucial role in various processes, such as fruit development and delaying aging in plant tissues.


Q7: A plant growth inhibitor hormone which causes wilting of leaves is  called:    (2024)
(a) 
Auxin  
(b) Cytokinin  
(c) Abscisic acid  
(d) Gibberellin  

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (c)
Abscisic acid is a plant hormone that acts as a growth inhibitor and helps plants respond to stress, such as drought. It causes the stomata to close, reducing water loss and leading to wilting of leaves when the plant is under stress.


Q8: Where are auxins synthesized? How do they promote phototropism?  (CBSE 2024)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (i) Synthesized at shoot tip/root tip
(ii) When light falls on one side of the plant, auxin diffuses towards the shady side of shoot. The concentration of auxin stimulates the cells to grow longer on the side of shoot which is away from light. Thus plant appears bent towards light/phototropism.


Q9: (a) (i) Define a reflex arc. Why have reflex arcs evolved in animals? Trace the sequence of events which occur, when you suddenly touch a hot object. (2024)
(ii) Name the part of nervous system which helps in communication between the central nervous system and other parts of the body. What are the two components of this system?
OR
(b) (i) Leaves of ‘chhui-mui’ plant begin to fold up and droop in response to a stimulus. Name the stimulus and write the cause for such a rapid movement. Is there any growth involved in the movement?
(ii) Define geotropism in plants. What is meant by positive and negative geotropism? Give one example of each type.

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a) (i) 

  • The pathway in which impulses travel during the reflex action is called a reflex arc. 
  • Because the thinking part of the brain is not fast enough/for quick response to avoid injury. 
  • Reflex arc:
    Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination

(ii) Peripheral Nervous System Components : Cranial Nerves; Spinal Nerves
OR
(b)  (i) 

  • Touch 
  • The shape of the leaves changes by changing the amount of water in  them. 
  • No 

(ii)  Growth of a part of plant in response to the pull of earth or gravity is called geotropism.

  • Positive geotropism − Movement of plant part towards the earth gravity. Example − Roots grow downwards
  • Negative geotropism − Movement of plant part away from the force of gravity. Example − Shoots grow upwards.


Q10: The correct sequence of events when someone’s hand touches a hot object unconsciously:  (2024)
(a)
Receptors in skin → Motor neuron → Relay neuron → Sensory neuron → Effector muscle in arm
(b) Receptors in skin → Relay neuron → Sensory neuron → Motor neuron → Effector muscle in arm
(c) Receptors in skin → Sensory neuron → Relay neuron → Motor neuron → Effector muscle in arm
(d) Receptors in skin → Sensory neuron → Effector muscle in arm → Motor neuron → Relay neuron

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (c)
Receptors in skin → Sensory neuron → Relay neuron → Motor neuron → Effector muscle in arm. 
When you touch something hot, the receptors in your skin detect the heat and send a signal through sensory neurons to the relay neurons in the spinal cord. Then, relay neurons send the signal to motor neurons, which activate the effector muscles in your arm to pull away quickly, helping you avoid injury.


Q11: Sense organ in which olfactory receptors are present is:  (2024)
(a) 
Nose  
(b) Skin  
(c) Tongue  
(d) Inner ear

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a)
Olfactory receptors, which are responsible for the sense of smell, are located in the nasal cavity of the nose. When you inhale, these receptors detect different scents and send signals to the brain, allowing you to identify various smells.


Q12: Taking the example of any two animal hormones along with their gland of secretion, explain how these hormones help (i) in growth and development and (ii) regulate metabolism, in the body.    (2024)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (i) 

  • Growth hormone.
  • Secreted by pituitary gland. 
  • It stimulates growth in all organs. 

(ii) 

  • Thyroxin.
  • Secreted by thyroid gland. 
  • It regulates carbohydrate, protein and fat metabolism for body growth. 

Previous Year Questions 2023

Q1: Sensory nerve of a reflex arc carries information from the receptor cells to the  (2023)
(a) spinal cord
(b) brain
(c) muscles of the effector organ
(d) bones of the receptor organ               

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a)
Sol: Reflex arc is pathway taken by nerve impulses and responses in a reflex action, i.e., from receptor organs like skin to spinal cord and from spinal cord to effector organs like muscles.


Q2: Name the part of brain which is responsible for the following actions:   (2023)
(i) Maintaining posture and balance
(ii) Beating of heart
(iii) Thinking
(iv) Blood pressure    

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (i) Cerebellum
(ii) Medulla oblongata
(iii) Cerebrum
(iv) Medulla oblongata


Q3: (a) How is the brain and spinal cord protected in human beings?  
(b) State one main function of
(i) Medulla and
(ii) Cerebellum. (2023)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a) Brain and spinal cord are protected by skeleton- brain by the cranium and spinal cord by vertebral column,
(b) (i) Medulla - It controls involuntary actions like heart beat, respiration, etc.
(ii) Cerebellum - It maintains posture and balance of body


Q4: Where are auxins synthesised in a plant? Which organ of the plant shows:
(i) Positive phototropism
(ii) Negative geotropism
(iii) Positive hydrotropism       (2023)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Auxin is synthesised at tip of the stem apices or shoots.
(i) Shoots
(ii) Shoots
(iii) Roots (bend towards water)


Q5: Name a plant hormone responsible for bending of a shoot of a plant when it is exposed to unidirectional light. How does it promote phototropism?      (2023)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Auxin is responsible for bending of a shoot of a plant when it is exposed to unidirectional light. In the presence of sunlight, the auxin present in the stem starts accumulating in the region away from sunlight, due to which the concentration of auxin in the region of the stem increases, resulting in bending of a shoot of a plant when it is exposed to unidirectional light. Thus, auxin promote phototropism that is the regulation of physiology or development in response to day length.


Q6: Select from the following the correct statement about tropic movement in plants. 
(a) It is due to stimulus of touch and temperature. 
(b) It does not depend upon the direction of stimulus received. 
(c) It is observed only in roots and not in stem. 
(d) It is a growth related movement. (CBSE 2023)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (d)
Tropic movements in plants are growth-related movements that occur in response to specific directional stimuli, such as light, gravity, water, or chemicals.
These movements are typically slow and involve growth in a particular direction, either towards (positive tropism) or away from (negative tropism) the stimulus.
Therefore, the correct answer is (d) It is a growth-related movement.


Q7: (A) Write the role of insulin in regulating blood sugar levels in human body. Mention the disease caused due to it. 
(B) How is the timing and the amount of release of insulin in the blood regulated? (CBSE 2023)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (A) Glucose enters the blood stream as soon as meals containing carbohydrates is digested by the body. As a result, the body's blood glucose levels rise. In order to direct all of the body's cells to take in the glucose, the pancreas releases chemical signals in the form of insulin. The majority of this glucose is consumed by the cells as energy. The liver and muscle cells take the extra glucose in the bloodstream and convert it to glycogen for later usage. In the end, insulin secretion reduces blood sugar levels. Diabetes is either caused due to the insufficient production of insulin by the pancreas or it may occur if the cells of the body are not effectively responding to the insulin produced. 
(B) Hormones are chemicals that our body secretes in a precise quantity and at a certain time. The release of hormones and the timing of their release are controlled by particular regulatory centres in our bodies. For instance: Regulation of insulin release - the pancreas secretes insulin, which regulates blood glucose levels. The higher blood glucose concentration affects how much insulin is produced. When blood glucose levels are really high, the pancreas releases more insulin.

Previous Year Questions 2020


Q1: Define geotropism. Draw a labelled diagram of a plant showing geotropic movement of its parts. (2020)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Geotropism refers to the upward and downward growth of shoots and roots respectively in response to the pull of earth or gravity. If the plant part moves in the direction of gravity, it is called positive geotropism. Likewise, if the plant part moves against the direction of gravity, it is termed as negative geotropism. A well labelled diagram of plant showing geotropism is:
Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination


Q2: A squirrel is in a scary situation. Its body has to prepare for either fighting or running away. State the immediate changes that take place in its body so that the squirrel is able to either fight or run. (2020)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: When squirrel is in a scary situation then its nervous system stimulates the adrenal glands to secrete more adrenaline hormone into blood. This adrenaline hormone increases heartbeat, breathing rate, blood flow into muscles and causes liver to put more stored glucose into its blood. All these actions of adrenaline hormone produces a lot of energy in squirrel’s body. In this way, squirrel prepares itself for fighting or running away action.


Q3: Why is chemical communication better than electrical impulses as a means of communication between cells in a multicellular organisms? (2020)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: In animals, the message communicated in the form of nerve impulses, from receptors to central nervous system and from letter to effectors is very quick. But nerve impulses can reach only those animal cells which are connected by the nervous tissue.
These cells after generation and transmission of nerve impulses, take some time to reset their mechanism before a new impulse is generated and transmitted. It means, cells cannot continuously generate and transmit electrical impulses. This is the reason most multicellular organisms use another means of communication called chemical communication. In chemical communication, information spreads out throughout the body by blood and its effects lasts longer. Chemical communication is however slow, but it can reach all the cells of body regardless of nervous connections.


Q4: A cheetah, on seeing a prey moves towards him at a very high speed. What causes the movement of his muscles? How does the chemistry of cellular components of muscles change during this event? (2020)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: The cheetah senses its prey by photoreceptors and the information is sent to the central nervous system. The response is then carried by neurons. Along with nervous system, the hormonal system also plays a role. Adrenaline hormone produced by the adrenal glands triggers the flight or fight action. On seeing a prey, these hormones are released into the cheetah's bloodstream. It speeds up heartbeat, breathing increases blood flow into leg muscles and causes liver to put more stored glucose into cheetah's blood. All these actions of adrenaline hormone produces a lot of energy which helps cheetah to run fast.


Q5: What constitutes the central and peripheral nervous systems? How are the components of central nervous system protected? Which signals will get disrupted in case of a spinal cord injury? (2020 C)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Central nervous system consists of brain and spinal cord. It contains centres for controlling various activities of the body. Peripheral nervous system consists of cranial nerves and spinal nerves. Components of the central nervous system are protected by:
(i) Brain is contained within the skull while the spinal cord is encircled by a series of vertebrae.
(ii) Meninges are a succession of tissue layers that reside within these bony structures.
(iii) Cerebrospinal fluid (CSF) is a clear, colourless, slightly alkaline fluid that surrounds the brain and spinal cord that protects from infections.
The following signals will get disrupted in case of a spinal cord injury:

  • Reflex action 
  • Impulses from various body parts will not be conducted to brain. 
  • Message from brain will not be conducted to various organs of the body.


Q6: (a) Name the hormone secreted by (i) Pituitary, and (ii) Thyroid stating one main function of each. Name the disorder a person is likely to suffer from due to the deficiency of the above mentioned hormones.
(b) How is the timing and amount of hormone released regulated ? Explain with an example. (2020 C)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a) (i) Pituitary secretes hormones GH, TSH, ACTH, FSH, LH, PRL, MSH, oxytocin and vasopressin. Growth hormone (GH) or somatotropic hormone controls the overall development of body, muscles, bones and tissues. Disorder related to thyroid gland: Goitre (enlarged thyroid gland) can occur due to inadequate dietary intake of iodine which result in low level of thyroid hormones (since iodine is essential to make thyroid hormones). Low levels of thyroid hormones stimulates pituitary gland to secrete more TSH, which causes thyroid gland enlargement. Hyposecretion of growth hormone (GH) during growth year results into dwarfism. This could happen due to the hyperactivity of the pituitary gland.
(ii) Thyroid gland secrete three hormones thyroxine (T4), triiodothyronine (T3) and calcitonin. Thyroxine and triiodothyronine 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. They promote growth of body tissues and development of mental faculties.
(b) Both the timing and amount of hormone released are regulated by feedback mechanism. For example, the pancreas involved in the secretion and release of hormone insulin when the positive feedback is signalled by the increased blood glucose level, the insulin sequester the glucose in adipose tissue and liver cells as glucose and fats respectively. When the blood glucose level decreases, the negative feedback will signal the pancreas to stop the secretion of insulin.


Q7: (a) Name one organ each where growth hormone is synthesized in man and plant.
(b) List the sequence of events that occur when a plant is exposed to unidirectional light, leading to bending of a growing shoot. Also name the hormone and the type of movement. (2020)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a) In humans, growth hormone is synthesized in the pituitary gland. In plants, growth hormone is synthesized in the apical meristem.
(b) When a plant is exposed to unidirectional light, the following sequence of events occur leading to bending of a growing shoot:
1. Photoreceptors in the shoot tip detect the direction and intensity of light.
2. Auxin, a plant hormone, is produced in higher concentrations on the shaded side of the shoot tip.
3. The higher concentration of auxin promotes cell elongation on the shaded side, causing the shoot to bend towards the light source.
4. The bending of the shoot towards the light is known as phototropism.
5. The bending helps the plant optimize its exposure to light, allowing for efficient photosynthesis.


Q8: Write in tabular form the location and function of the hormones secreted by each of the following glands present in the human body: (A) Pituitary gland 
(B) Thyroid gland 
(C) Pancreas (CBSE 2020)

Ans: (A) Pituitary Gland

  • Location: At the bottom of the hypothalamus at the base of the brain.
  • Function: Secretes growth hormone, which regulates the growth and development of the body.

(B) Thyroid Gland

  • Location: In the neck region.
  • Function: Secretes thyroxine hormone, which regulates the metabolism of carbohydrates, proteins, and fats in the body.

(C) Pancreas

  • Location: Just below the stomach.
  • Function: Secretes insulin hormone, which lowers the blood sugar level.

Previous Year Questions 2019


Q1: What is a nerve impulse? State the direction followed by a nerve impulse while travelling in the body of an organism. (2019)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: A nerve impulse is a gradual physicochemical change in a nerve fibre's membrane that occurs after stimulation. This impulse travels from the dendrite to the cell body and then along the axon to its end.


Q2: Draw a diagram of neuron and name and label the part
(a) where information is acquired,
(b) through which information travels as an electric impulse, and
(c) where the electric impulse must be converted into a chemical signal for onward transmission. (2019 C)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Diagrammatic representation of a neuron is as follows:
Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination


Q3: Why does the flow of signals in a synapse from axonal end of one neuron to dendritic end of another neuron take place but not in the reverse direction? Explain. (NCERT.AI 2019)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: At the synapse (functional junction between neurons), axon terminal comes in close proximity to the dendron terminal of next neuron. Axon terminal is expanded to form pre-synaptic knob and the other dendrite terminal forms post-synaptic depression. In between the two, lies a narrow fluid filled space called synaptic cleft. As the nerve impulse reaches the pre-synaptic knob, the synaptic vesicles get stimulated to release neurotransmitter in the synaptic cleft. The neurotransmitter molecules diffuse across the gap to come in contact with post-synaptic membrane. In this way, nerve impulse passes across the minute gap to stimulate dendron of another neuron. The synapse acts as a one-way valve to conduct impulse in one direction only. This is so because chemical substance called neurotransmitter is secreted only on one side of the gap, i.s., on axons side. It carries impulse across the synapse and passes it to the dendron of the other neuron. In this way, impulses travel across the neurons only in one direction, i.e., from axon of one neuron to dendron of other neuron through a synapse.


Q4: List in tabular form three distinguishing features between cerebrum and cerebellum. (2019)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Distinguishing features between cerebrum and cerebellum:
Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination


Q5: How do auxins promote the growth of a tendril around a support? (2019)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: When tendrils 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 is caused by the action of auxin hormone. Less auxin occurs on the side of contact as compared to the free side. As a result, auxin promotes growth on the free side and the tendrils coil around the support.


Q6: State the function of each of the following plant hormones:
(a) Gibberellins
(b) Auxins
(c) Abscisic acid   (2019 C)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a) In genetically dwarf plants, the length of internode is very much reduced but the number of nodes remains the same. Gibberellins overcome the phenotypic expression of dwarfism in certain plants. Besides general increase in stem length, gibberellins specifically induce internodal growth in some genetically dwarf varieties of plants like pea and maize. Gibberellins, however, have little or no effect when they are applied to the normal plant.
(b) Auxin is the plant hormone which promote cell enlargement and cell differentiation in plants. It also plays a role in apical dominance (i.e., the phenomenon in which presence of apical bud does not allow the nearby lateral buds to grow). When the apical bud is removed, the lateral buds sprout. This produces dense bushy growth. The phenomenon is widely used in tea plucking. Apical bud inhibits the growth of lateral buds by release auxin.
(c) Abscisic acid or ABA is a plant hormone or phytohormone which acts as growth inhibitor. It promotes dormancy in seeds and buds, abscission (falling of leaves) and senescence in leaves and thus inhibits growth of plant.


Q7: What are plant hormones? Name the plant hormones responsible for the following:
(i) Growth of stem
(ii) Promotion of cell division
(iii) Inhibition of growth
(iv) Elongation of cells   (NCERT, Delhi 2019)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Plant hormones or phytohormones are chemical substances produced naturally in plants and capable of translocation and regulating one or more physiological processes when present in low concentration. These are also known as plant growth substances or plant growth regulators.
The plant hormones responsible for different functions are as follows:
(i) Growth of stem: Gibberellins (Gibberellic acid) promote growth in stems.
(ii) Promotion of cell division: Cytokinins promote cell division in plants.
(iii) Inhibition of growth: ABA (Abscisic acid) promotes dormancy in seeds as well as in buds and thus inhibits growth.
(iv) Elongation of cells: Auxin and cytokinin both cause cell elongation.


Previous Year Questions 2018


Q1: (a) What are sensory and motor neurons? Write their function.    (CBSE 2018C)
(b) Different parts of brain are associated with specific functions. Name the part of human brain which perform the following functions:
(i) Sensation of feeling full
(ii) Vomiting

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a) Two types of neurons are:
(i) Sensory neurons - They transmit information from the receptors to the central nervous system.
(ii) Motor neurons - They transmit information from the brain to the effector organs.
(b) 

(i) Forebrain (a centre for hunger)
(ii) Hindbrain (medulla)

Previous Year Questions 2017


Q1: (a) Name the part of human brain which controls:  (2017)
(i) voluntary actions (ii) involuntary actions.
(b) State the significance of peripheral nervous system. Name the components of this nervous system and distinguish between their origins.

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a) (i) Voluntary actions are controlled by the cerebrum (the forebrain).
(ii) Involuntary actions are controlled by mid-brain (the medulla oblongata).
(b) Peripheral nervous system facilitates the communication between central nervous system and other body parts.
Components of peripheral nervous system are:
(i) Cranial Nerves: Originating from brain.
(ii) Spinal Nerves: Originating from spinal cord.


Q2: (a) Name the gland that secrete:
(i) insulin, (ii) thyroxin.
(b) Explain with an example how the timing and amount of hormone secreted are regulated in a human body.  (2017)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a) Gland that secretes:
(i) Insulin - Pancreas
(ii) Thyroxine - Thyroid gland
(b) The timing and amount of hormone secreted are regulated by the “Feedback mechanisms”. For example:
(i) High glucose level in blood induces the pancreatic cells to produce more insulin which converts glucose to glycogen.
(ii) Low glucose level in the blood does not induce the pancreatic cells to produce insulin so that less conversion of glucose to glycogen occurs.


Q3: (a) State the role performed b y plant hormones. Name a plant hormone which is essential for cell division.
(b) Name and explain the role of plant hormone involved in phototropism.  (2017)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a) Role of plant hormones:
Chemical control in the plants is performed through plant hormones. They help to coordinate growth, development and responses to the environment.
Plant hormones auxin and cytokinin help in cell division.
(b) When growing plants detect light, a hormone called auxin, synthesised at the shoot tip, helps the cells to grow longer. When light is coming from one side of the plant, auxin diffuses towards the shady side of the shoot. This concentration of auxin stimulates the cells to grow longer on the side of the shoot which is away from light.


Q4: What is geotropism? Draw a labelled diagram of a potted plant showing positive geotropism and negative geotropism  (2017)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: The downward growth of roots due to attraction by earth’s gravity and upward growth of shoots against it, is geotropism.Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination


Q5: How does the feedback mechanism regulate hormone secretion? Explain with the help of an example.  (2017)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Feedback system is a regulatory mechanism in which the presence of a certain level of hormone promotes or inhibits its further formation.
Regulation of thyroxine production by its concentration in blood is an example of hormonal feedback system. If the level of thyroxine is more in the blood, this is detected by hypothalamus, which stops producing thyroid-stimulating hormone (TSH). Non-availability of TSH results in failure of thyroid to produce thyroxine. This automatically results in reduction of thyroxine in blood.
But if concentration of thyroxine is low in the blood, hypothalamus produces TSH which then passes into circulatoray system and reaches thyroid gland. Thyroid now begins to secrete more thyroxine.


Q6: State the source of secretion and function of the following hormones:  (2017)
(i) Thyroxin 
(ii) Insulin 
(iii) Growth hormone.

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: 

HormoneSourceFunction
(i) ThyroxinThyroid glandRegulates metabolism of carbohydrates, fats and proteins.
(ii) InsulinPancreasPromotes sugar absorption from blood thereby regulating blood-sugar level.
(iii) Growth hormonePituitary glandRegulates overall growth of the body.


Q7: What are trophic levels? Make a food chain of four trophic levels.  (2017)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Each step/level of the food chain where energy transfer takes place is called a trophic level.
Example: (i) Plants → Grasshopper Frog → Snake
(ii) Plants Deer → Hyena Tiger


Q8: Different parts of brain are associated with specific functions. Name the part of human brain which performs the following functions:    (CBSE 2017-18 C)
(a) Sensation of feeling full
(b) Vomiting
(c) Picking up a pencil
(d) Riding a bicycle.

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a) Cerebrum - Forebrain
(b) Medulla - Hind brain
(c) Cerebellum - Hind brain
(d) Cerebellum - Hind brain


Q9: (a) What are phytohormones? List four types of phytohormones. Where are these hormones synthesised?
(b) What happens when a growing plant detects light? Explain in brief. (Board Term I, 2017)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a) Phytohormones are chemical substances that regulate various physiological processes in plants. They are produced naturally by plants and control growth, development, and responses to environmental stimuli. 
Four types of phytohormones are:

  • Auxins: These hormones regulate cell elongation, apical dominance, and phototropism. They are mainly synthesized in the apical meristem, young leaves, and developing seeds.
  • Gibberellins: These hormones promote stem elongation, seed germination, and fruit development. They are primarily synthesized in the apical meristem, young leaves, and developing seeds.
  • Cytokinins: These hormones promote cell division and differentiation, delay senescence, and regulate apical dominance. They are synthesized in actively growing tissues such as roots, embryos, and fruits.
  • Abscisic Acid: This hormone controls seed dormancy, stomatal closure, and stress responses. It is synthesized in mature leaves, fruits, and seeds.

(b) When a growing plant detects light, it triggers a series of responses known as photomorphogenesis. The plant's photoreceptors, specifically phytochrome and cryptochrome, detect the light signal and initiate various physiological changes. These changes include:

  • Phototropism: The plant bends towards the light source, which is controlled by auxin distribution in the stem.
  • Chloroplast movement: Chloroplasts within the plant cells move to optimize light absorption for photosynthesis.
  • Stomatal opening: Light stimulates the opening of stomata, allowing for gas exchange and transpiration.
  • Flowering: Light is crucial for triggering the flowering process in many plants.

Overall, the detection of light by plants is essential for their growth, development, and ability to respond to their environment. 


Q10: Draw a diagram of the cross-sectional view of human brain as given below on your answer sheet and label:    (CBSE 2017-18 C)
(а) The part that helps in performing voluntary actions. 
(b) The part that controls salivation and vomiting. 
(c) The largest part of forebrain. 
(d) A fluid that protects the brain. 
(e) Meninges.

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a) Cerebrum 
(b) Medulla
(c) Cerebrum
(d) Cerebrospinal fluid
(e) Meninges or three membranes covering the brain.Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination


Previous Year Questions 2016


Q1: Name the two components of central nervous system. How are they protected? Name the component which is considered as highest coordinating centre of the body. Describe its three regions.   (CBSE 2016)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Brain and spinal cord are the two components of central nervous system.
Human brain is protected by a bony skull, also called as cranium. Internal to the skull it is covered from outside by three membranes called meninges. In between the meninges there is a fluid called as cerebrospinal fluid. Beneath the membranes brain is subdivided into three major parts namely fore-brain, midbrain and hind brain.
Brain is considered as highest coordinating centre of the body.
Its three regions are given below:

  • Fore-brain is the main thinking part of the brain. It has different regions or areas such as:
    (i) Sensory area - It receives sensory impulses from various receptors.
    (ii) Auditory area - It is concerned with hearing.
    (iii) Olfactory area - It is concerned with smell.
    (iv) Gustatory area - It is concerned with taste.
    (v) Optic area - It is concerned with sight.
    (vi) Association area - This area interprets various sensory informations and makes decision how to respond.
    (vii) Motor area - Decisions made by association area are passed on to this area which control the movement of voluntary muscles.
  • Midbrain comprises of four lobes. So it is also known as copra quadrigemina. Actions of involuntary muscles are controlled by the mid-brain and hind-brain.
  • Hind-brain comprises of cerebellum, pons varolii and medulla oblongata. Cerebellum is the second largest part of brain that coordinates muscular activity of the body as well as maintains body equilibrium or posture. Pons connects cerebellum and medulla oblongata and functions as a relay centre among different parts of brain. It possesses pneumotaxic area of respiratory centre. Medulla oblongata lies below the cerebellum and continues behind the spinal cord. Involuntary actions like blood pressure, salivation and vomiting are controlled by the medulla in the hind-brain.


Q2: With the help of suitable examples explain the terms phototropism, geotropism and chemotropism.    (CBSE 2016)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: The stimulus oriented movement of plant or plant part is called tropism. The direction of movement is related to the direction of stimulus. These movements are always growth oriented movements. They are of different types namely phototropism (growth movement in response to light), hydrotropism (water), geotropism (force of gravity), thigmotropism (contact) and chemotropism (chemicals).

  • Phototropism is a directional growth movement which occurs in response to unidirectional exposure to light. The region of photoreception is shoot apex where auxin is produced. Auxin moves from the illuminated region to the shaded region. This causes more growth on the dark side of the stem causing it to bend towards the source of light. Movement of shoot towards light is called phototropism.
  • Roots are positively geotropic and negatively phototropic. Shoots are positively phototropic and negatively geotropic.
  • Growth of pollen tube inside the style, ovary and ovule in response to the chemicals produced by them is an example of chemotropism.


Q3: (a) Define hormone. Write four characteristics of hormones in humans.
(b) Name the disorder caused by the following situations:
(i) Under secretion of growth hormone.
(ii) Over secretion of growth hormone.
(iii) Under secretion of insulin.
(iv) Deficiency of iodine.     (CBSE 2016)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a) Hormones are chemical informational molecules that are required in minute quantities and are directly poured in the blood stream by the glands. They act on a specific organ called target organ. So their site of production varies from site of action.
Their characteristics are:

  • They are poured into blood stream.
  • Are generally proteinaceous or steroid.
  • Their secretion is regulated by feedback mechanism.
  • Their site of action and secretion is different.

(b) 
(i) Dwarfism
(ii) Gigantism
(iii) Diabetes
(iv) Goitre.


Q4: Name the hormone which is released into the blood when its sugar level rises. Name the organ which produces this hormone and its effect on blood sugar level. Also, mention the digestive enzymes secreted by this organ with one function of each.     (CBSE 2016)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: When blood sugar level rises in blood, a hormone named ‘insulin" is produced by β-cells of islet of Langerhans in the organ Pancreas. Pancreas also produces pancreatic juice which contains pancreatic enzymes such as trypsin, pancreatic amylase and pancreatic lipase.
Insulin promotes glucose absorption by individual cells and absorption and formation of glycogen in liver and muscles. This reduces glucose level in blood. As soon as the blood sugar comes to normal the pancreatic cells stops secretion of insulin.
Pancreas secretes slightly alkaline pancreatic juice which contains three major following enzymes:

  • Trypsin which digests proteins.
  • Lipase which digests fats.
  • Amylase which digests carbohydrates.


Q5: What are phytohormones? List four types of phytohormones. Where are these synthesised?     (CBSE 2016)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Plants possess chemical coordination. They respond to stimuli by secreting chemical substances called as plant growth regulators. They either stimulate or retard growth. Five major types of plant growth hormones are auxins, gibberellins, cytokinins, abscisic acid and ethylene.
These plant growth regulators are also known as phytohormones.
These are synthesised at shoot apices, leaves, developing embryos, root tips etc.


Q6: Name the plant growth hormone which is synthesized at shoot tip. Explain with the help of a diagram why does a plant bend towards light during growth.     (CBSE 2016)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (i) Auxin is a phytohormone which is synthesized at shoot tip.
(ii) When a plant is exposed to light coming from one side of the plant then auxin located at the shoot tip diffuses towards the shaded side of the shoot. High concentration of  auxin in the shaded region stimulates the cells  to grow longer in comparison to the region  exposed to light. So the shoot tends to bend towards the light.

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination


Q7: Name the hormone which regulates carbohydrate, protein and fat metabolism in our body. Which gland secretes this hormone? Why is it important for us to have iodised salt in our diet?     (CBSE 2016)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Thyroxine regulates carbohydrates, protein and fat metaboslism in our body.
Thyroxine is secreted from thyroid gland. Deficiency of iodine in our food causes (goitre) where the thyroid gland to enlarges as it needs to absorbs more amount of iodine. Iodine is required to make thyroxine. Therefore, iodine is added to salt to supplement iodine requirement.


Q8: Name the two components of central nervous systems in humans.     (CBSE 2016)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: The two components of the Central Nervous System in humans are the brain and spinal cord.


Q9: In the absence of muscle cells, how do plant cells show movements?     (CBSE 2016)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Plants do not have nervous system and muscles. Even then they exhibit well coordinated and controlled movements. Plants possess chemical coordination. They respond to stimuli by secreting chemical substances called plant growth regulators. They either stimulate or retard growth. Five major types of plant growth hormones are auxins, gibberellins, cytokinins, abscisic acid and ethylene.
Certain changes in the orientation of plant parts in relation to other parts caused by intrinsic or external stimuli are non-directional, growth independent movements. They are referred to as nastic movements. Thus, plants show movements due to growth or change in turgor pressure.


Q10: (a) Write two points of differences between enzymes and hormones.     (CBSE 2016)
(b) Name one endocrinal gland in our body which performs dual function. Write the functions.

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: (a) Differences between enzymes and hormones:

EnzymesHormones
(i) Are produced by exocrine glands.(i) Are produced by endocrine glands.
(ii) Site of secretion and action is same.(ii) Site of secretion and action is different.

(b) Pancreas performs dual function. It produces enzymes like Trypsin, Lipase etc., which aid in digestion. It also produces insulin hormone which regulates blood-sugar level.


Q11: Name the system which facilitates the communication between the central nervous system and the other body parts of the body.    (CBSE 2016)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Peripheral nervous system.


Previous Year Questions 2015


Q1: What is synapse? In a neuron cell how is an electrical impulse created and what is the role of synapse in this context?   (CBSE 2015)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Synapse is the junction between two adjustment neuron or nerve cells, i.e. between axon ending of one and the dendrite of the next.
Transmission of Nerve Impulse. The information acquired at the end of the dendritic tip of a neuron sets off a chemical reaction which creates an electrical impulse. This impulse travels from the dendrite to the cyton along the axon to its end. At the end of the axon, the electrical impulse sets off the release of some chemicals, which cross the synapse and start a similar electrical impulse in a dendrite of the next neuron. In this way nerve impulses travel in the body.
Synapse helps in transmitting impulses from one neuron to another.


Q2: “As the blood sugar level in our body falls insulin secretion is reduced.” Justify this statement in the reference of feedback mechanism that regulates the timing and amount of hormone released.   (CBSE 2015)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Insulin is a hormone that regulates our blood sugar level by converting it into glycogen which can be stored.
Hence, if there is more levels of sugar in blood then more insulin is produced and if the sugar level is less then insulin production is also reduced.
This is because of feedback mechanism where the blood sugar itself acts as a feedback for more or reduced insulin synthesis.


Q3: State the role played by ovaries in a human female.   (CBSE 2015)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Roles of ovary:

  • Ovaries produce female gametes, ova.
  • It also produces a female sex hormone called estrogen. Estrogen is essential for development of secondary sex organs in female as well as secondary sexual characters like high pitch voice, development of mammary glands.


Q4: What is meant by reflex-action? With the help of a labelled diagram trace the sequence of events which occur when we touch a hot object.   (CBSE 2015)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: Reflex action is defined as an unconscious, automatic and involuntary response of effector, i.e. muscle and gland to a stimulus which is monitored through the spinal cord.

Class 10 Science Chapter 6 Previous Year Questions - Control and CoordinationSequence of events when we touch a hot object are:

  • Receptor organ skin receives the stimulus and activates a sensory nerve impulse.
  • Sensory neuron carries the message in the form of sensory impulse to the spinal cord.
  • The spinal cord acts as a modulator. The neurons of the spinal cord transmit the sensory nerve impulses to the motor neuron.
  • Motor nerve conducts these impulses to the effector organ hand which responds by pulling back the hand away from the hot object.


Q5: Write the names of the hormones secreted by the pituitary gland and adrenal gland. State their functions in the body.   (CBSE 2015)

Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination  View Answer

Ans: 
Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination

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FAQs on Class 10 Science Chapter 6 Previous Year Questions - Control and Coordination

1. What are the main components of the control and coordination system in humans?
Ans. The main components of the control and coordination system in humans include the nervous system and the endocrine system. The nervous system consists of the brain, spinal cord, and nerves, which help in rapid responses to stimuli. The endocrine system comprises glands that secrete hormones, which regulate slower, long-term processes in the body.
2. How do neurons transmit signals in the nervous system?
Ans. Neurons transmit signals through a process called electrochemical signaling. When a neuron is stimulated, it generates an electrical impulse called an action potential. This impulse travels along the axon to the synapse, where neurotransmitters are released to transmit the signal to the next neuron, muscle, or gland.
3. What is the role of hormones in coordination?
Ans. Hormones play a crucial role in coordination by acting as chemical messengers that regulate various physiological functions in the body. They are secreted into the bloodstream by glands and target specific organs or tissues to influence processes such as growth, metabolism, and mood, ensuring that the body's functions remain balanced.
4. Explain the difference between voluntary and involuntary actions.
Ans. Voluntary actions are conscious and intentional movements that are controlled by the brain, such as walking or writing. In contrast, involuntary actions occur automatically without conscious thought, such as reflex actions or the beating of the heart, which are regulated by the autonomic nervous system.
5. What is the significance of reflex actions in the control and coordination system?
Ans. Reflex actions are significant because they provide a rapid response to potentially harmful stimuli, protecting the body from injury. They are automatic and occur through a reflex arc, which involves sensory neurons, interneurons, and motor neurons, allowing for quick reactions without the delay of processing in the brain.
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