11. The Regulators of Life - .::Login Page::.mt-iconnect.com/MTE_Content/MTE/Notes_Question Paper/X...Transpiration takes place in the leaves through stomatal openings. Ans. True

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The Regulators of Life11.

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Q.I (A) Choose the correct alternatives and rewrite the complete sentences :1. .................... is necessary to obtain energy from glucose and fatty acid.

(a) Oxygen (b) Hydrogen(c) Water (d) Nitrogen

2. In certain sensitive plants like Mimosa, movement is in response to thestimulus of ..................... .(a) gravity (b) air(c) light (d) touch

3. The movement of the plant in response to the stimulus of light is called..................... movement.(a) gravitropic (b) hydrotropic(c) phototropic (d) chemotropic

4. When light falls on a part of growing plant, a hormone called .....................is synthesized at the tip of the shoot.(a) auxin (b) abscissic acid(c) gibberellins (d) cytokinins

5. The movement of the root system towards the stimulus of gravity is called..................... movement.(a) gravitropic (b) hydrotropic(c) phototropic (d) chemotropic

6. The movement of the root system towards the stimulus of water is called..................... movement.(a) gravitropic (b) hydrotropic(c) phototropic (d) chemotropic

7. ..................... hormones help in the growth of the stem.(a) Auxins (b) Abscissic acid(c) Gibberellins (d) Cytokinins

8. ..................... hormones promote cell division.(a) Auxins (b) Abscissic acid(c) Gibberellins (d) Cytokinins

9. ..................... is a plant hormone which inhibits growth wilting of leaves.(a) Auxin (b) Abscissic acid(c) Gibberellins (d) Cytokinins

10. The ..................... is the main thinking part of the brain.(a) cerebrum (b) cerebellum(c) medulla oblongata (d) spinal cord

11. The brain can stay alive for ..................... without oxygen.(a) 4-6 hours (b) 5-6 hours(c) 24 hours (d) 4-6 minutes

Answers :1. Oxygen 2. touch3. phototropic 4. auxin5. gravitropic 6. hydrotropic7. Gibberellins 8. Cytokinins9. Abscissic acid 10. forebrain or cerebrum

11. 4-6 minutes.

Q.I (B) Fill in the blanks :*1. ..................... do not possess a nervous system.*2. Response to the stimulus of touch is called ..................... whereas response

to the stimulus of chemicals is called as ..................... .

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*3. Brain is the main ..................... centre of the body.*4. The loss of water from the plants is known as ..................... .5. ..................... refers to the systematic regulation of various activities.6. ..................... means the orderly execution of the activities.7. Transpiration takes place in the leaves through the ..................... .8. The food is mixed with the ..................... in the saliva secreted by the

salivary glands.9. The movement or growth of any part of a plant in response to an external

stimulus is called ..................... .10. The plants use ..................... means to transfer information from one cell

to another.11. The nerves are composed of neurons and ..................... .12. The neurons are specialized cells capable of transmitting ..................... .13. ..................... neurons conduct impulses from the sense organs to the

brain and spinal cord.14. ..................... neurons conduct impulses from the brain and spinal cord to

the effector organs.15. ..................... neurons perform the integrative functions of the nervous

system.16. ..................... keeps the CNS well nourished and also protects it by absorbing

mechanical shocks.17. The chemical control is brought about by chemical substances called

..................... .18. The hormones are secreted by the ..................... glands.19. Endocrine glands are also known as the ..................... glands.20. Hormones are also referred to as ..................... .21. Insect ..................... is under hormonal control.22. In frogs ..................... secretion stimulates the metamorphosis from tadpole

to adult frog.23. In the ....................., hormones induce colour changes and are influential

in regulating development.24. The left hemisphere of the brain has ..................... more neurons than

the right hemisphere.25. ..................... of blood flows through the brain every minute.26. In certain coelenterates like ....................., the nervous system is at a

very primitive stage of developments.

Answers :1. Plants 2. seismonastic movement, chemotropism3. thinking 4. transpiration5. Control 6. Co-ordination7. stomatal openings 8. enzymes9. tropism or tropic movement 10. electrochemical

11. neuroglia 12. electrochemical impulses13. Sensory 14. Motor15. Association 16. Cerebrospinal fluid (CSF)17. hormones 18. endocrine19. ductless 20. chemical messengers21. metamorphosis 22. thyroid23. arthropods 24. 186 millions25. 750-1000 ml 26. hydra.


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Q.I (C) Match the following :1. Column I Column II(i) Seismonastic movement (a) Stimulus of gravity

(ii) Phototropic movement (b) Stimulus of chemicals(iii) Gravitropic movement (c) Stimulus of light(iv) Hydrotropic movement (d) Stimulus of touch(v) Chemotropic movement (e) Stimulus of water

Ans. (i - d), (ii - c), (iii - a), (iv - e), (v - b).

2. Column I Column II(i) Folding of leaflets in Mimosa (a) Chemotropism

pudica(ii) Growth of pollen tube towards (b) Seismonastic

the ovules(iii) Bending of plant towards light (c) Hydrotropism(iv) Movement of roots towards water (d) Phototropism

Ans. (i - b), (ii - a), (iii - d), (iv - c).

3. Column I Column II(i) Gibberellins (a) Promoting cell division in fruits and

seeds(ii) Cytokinins (b) Tip of shoot to grow longer

(iii) Abscissic acid (c) Promoting growth of stem(iv) Auxins (d) Wilting of leaves

Ans. (i - c), (ii - a), (iii - d), (iv - b).

4. Column I Column II(i) Lotus plant (a) Curl inwards at the touch of an

insect, trapping it(ii) Tube rose plant (b) Open in morning

(iii) Tentacles of Drosera (c) Bursts open scattering the seeds.(iv) Fruit of Balsam plant (d) Open at night

Ans. (i - b), (ii - d), (iii - a), (iv - c).

5. Column I Column II(1) CNS (a) Comprises of nerves present in

involuntary organs like heart,stomach, lungs, etc.

(2) PNS (b) Comprises of the ductless glandssecreting hormones

(3) ANS (c) Comprises of brain and spinal cord(4) Endocrine system (d) Comprises of cranial nerves and

spinal nervesAns. (i - c), (ii - d), (iii - a), (iv - b).

6. Column I Column II(i) Taste buds at the tip of the tongue (a) Detect salty and sour tastes

(ii) Olfactory receptors (b) Detect bitter tastes(iii) Taste buds at the back of the (c) Sense of smell

tongue(iv) Taste buds at the sides of the (d) Detect sweet tastes

tongueAns. (i - d), (ii - c), (iii - b), (iv - a).


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7. Column I Column II(i) Medulla oblongata (a) Reflex arc

(ii) Spinal cord (b) Main thinking part of brain(iii) Cerebellum (c) Involuntary activities like

breathing, blood flow, etc.(iv) Cerebrum (d) Voluntary movements and

maintaining balance of the bodyAns. (i - c), (ii - a), (iii - d), (iv - b).

Q.I (D) State whether the following statements are true or false. If falsewrite the corrected statement :

1. The loss of water from the plants is known as translocation.Ans. False. The loss of water from the plants is known as transpiration.

2. Transpiration takes place in the leaves through stomatal openings.Ans. True.

3. There is growth involved in the seismonastic movement exhibited by plants.Ans. False. There is no growth involved in the seismonastic movement exhibited

by plants.4. Unlike animals, plants do not have a nervous system or muscular system.

Ans. True.5. When light falls on growing plants, the hormone auxin is synthesized at

the tip of the root.Ans. False. When light falls on growing plants, the hormone auxin is synthesized

at the tip of the shoot.6. Plants possess specialized tissue for conduction of information of touch to

bring about movement.Ans. False. Plants use electrochemical means to transfer the information.

7. The central nervous system comprises of all the nerves.Ans. False. The CNS comprises of brain and the spinal cord.

8. The neuroglia are supportive cells which assist the neurons in theirfunction.

Ans. True.9. All the information from our environment is picked up by axons of a neuron.

Ans. False. All the information from our environment is picked up by thespecialized tips of dendrites of a neuron.

10. Muscle cells possess special kinds of proteins which help them changetheir shape.

Ans. True.11. Sensory neurons conduct impulses from sense organs to the brain and

spinal cord.Ans. True.12. Motor neurons conduct impulses from effector organs like muscles and

glands to brain and spinal cord.Ans. False. Motor neurons conduct impulses from brain and spinal cord to effector

organs.13. Human brain, on an average, weighs 1300 - 1400 gram.

Ans. True.14. Cranial nerves arise from spinal cord.

Ans. False. Cranial nerves arise from the brain whereas spinal nerves arisefrom the spinal cord.

15. The forebrain or the cerebrum is the main thinking part of the brain.Ans. True.


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16. Nerve impulses are slower and long lasting whereas hormonal action israpid and of short duration.

Ans. False. Nerve impulses are rapid and of short duration and hormonal actionis much slower and long lasting.

17. The medulla oblongata is a component of the mid brain.Ans. False. The medulla oblongata is a component of the hind brain.18. The medulla oblongata controls vital involuntary activities like blood flow,

breathing, sneezing, etc.Ans. True.19. Affarent nerves carry impulses from the brain to the sensory organs.

Ans. False. Affarent nerves carry impulses from the sensory organs to the nerves.

Q.I (E) Find the odd man out :1. Digestion, Transpiration, Circulation, Excretion.

Ans. Transpiration. It is a process which takes place in plants whereas therest are processes occurring in animals.

2. Seismonastic, Phototropic, Chemotropic, HydrotropicAns. Seismonastic. It is a growth independent movement whereas rest are

growth dependent movements.3. Gibberellins, Auxins, Cytokinins, Thyroxine.

Ans. Thyroxine. It is a growth hormone in animals whereas the rest are growthhormones in plants.

4. Spinal cord, Cerebrum, Cerebellum, Medulla oblongata.Ans. Spinal cord. It is not a part of the brain, whereas the rest are the three

regions of the brain.5. Dendrite, Cell body, Axon, Synapse.

Ans. Synapse. It is a microscopic gap between two neurons whereas the restare main parts of the neuron.

6. Auxin, Gibberellins, Insulin, Abscissic acid.Ans. Insulin. It is a hormone in animals whereas the rest are hormones in plants.

Q.I (F) Write the correlated terms :1. Loss of water : Transpiration :: Ascent of sap : ....................... .

Ans. Translocation.2. Movement of shoot system : Phototropic :: Movement of root system :

....................... .Ans. Gravitropic and hydrotropic.

3. Brain : Cranium :: Spinal cord : ....................... .Ans. Vertebral column.

4. Cavities of the brain : Ventricles :: Cavity of the spinal cord : ....................... .Ans. Central canal.

5. Central nervous system : Brain and spinal cord :: Peripheral nervous system: ....................... .

Ans. Nerves.6. Involuntary activities : Medulla oblongata :: Balance of the body :

....................... .Ans. Cerebellum.

7. Tip of the tongue : Sweet taste :: Back of the tongue : ....................... .Ans. Bitter taste.

8. Bending of stem towards light : Phototropism :: Growth of pollen tube towardsovules : ....................... .

Ans. Chemotropism.9. Growth of the stem : Gibberellins :: Wilting of leaves : ....................... .

Ans. Abscissic acid.


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Q.II (A) Name the following :*1. Growth of plant in response to external factors.

Ans. Tropism.*2. Maintenance of steady state by different systems in an organism.

Ans. Homoeostasis.*3. Cells those assist the neurons in their function.

Ans. Neuroglia.*4. The small gap between the consecutive neurons.

Ans. Synapse.*5. Part of the brain that co ordinates the voluntary movements.

Ans. Cerebellum.6. The bony structure protecting the brain.

Ans. Cranium (skull).7. The bony structure protecting the spinal cord.

Ans. Vertebral column (Backbone).8. Protective membranes in the space between the soft CNS and bone.

Ans. Meninges.9. Cavities present on the different parts of the brain.

Ans. Ventricles.10. Long cavity present in the spinal cord.

Ans. Central canal.11. Fluid present in the cavities of brain, spinal cord and space between

meninges.Ans. Cerebrospinal fluid.

Q.II (B) Define the following :1. Homoeostasis.

Ans. The maintenance of the steady state by different systems of an organismfor its optimal functioning because of a perfect co-ordination is calledhomoeostasis.

2. Tropism OR Tropic movements.Ans. The movement or growth of any part of a plant in response to an external

stimulus is called tropism or tropic movements.3. Reflex action.

Ans. Any sudden action in response to some happening in the environment,without thinking about it or without feeling in control of our reactions iscalled reflex action.

Q.III (A) Give scientific reasons :*1. Roots of plants go away from light.

Ans. 1. The roots of plants respond to the stimulus of gravity and water.2. These responses are called gravitropic and hydrotropic movements

respectively.3. Plants absorb water in which minerals are dissolved, from the soil with

the help of their roots.4. Therefore, roots of plants go away from light.

*2. Hormones secreted by the endocrine glands are present everywhere inthe body.

Ans. 1. The chemical control is brought about by chemical substances called hormones.2. These hormones are secreted by endocrine glands or ductless glands.3. These glands do not have any duct to store or transport their secretions.4. Thus, on production these hormones are directly released into the

blood stream.


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5. Due to this, the hormones reach everywhere in the body, though thegland secreting them is located in a particular place.

6. Therefore, hormones secreted by the endocrine glands are presenteverywhere in the body.

*3. Insulin plays an important role in controlling the sugar level of blood.Ans. 1. Insulin is a hormone which controls the sugar level of blood.

2. It is very important that insulin should be secreted according to theamount of sugar in the blood.

3. The required quantity of insulin released and the time of released areregulated by feedback mechanisms.

4. When the sugar level of blood rises, it it detected by the cells of thepancreas which respond to the situation by producing more insulin sothat the sugar level comes back to normal.

5. On the other hand, as the sugar level of the blood falls, the secretion ofinsulin is reduced.

6. Therefore, insulin plays an important role in controlling the sugar levelof blood.

4. Tendril entwines itself around the object and clings to it.Ans. 1. Tendrils are sensitive to touch.

2. When they come in contact with any object, the portion of the tendril whichis in contact, becomes sluggish whereas growth is faster at the other portion.

3. This causes the tendril to entwine itself around the object and thuscling to it.

5. Reflex arcs are evolved in animals.Ans. 1. In animals, the thinking process of the brain is a bit slow.

2. In many animals, specially lower animals the complex neuron networkneeded for thinking is not there or is not well developed.

3. Hence reflex arcs have been evolved as efficient ways of functioning inthe absence of the true thought process.

4. However, in spite of the presence of complex neuron networks, reflexarcs continue to be more efficient for quick responses.

Q.III (B) Answer the following questions in short :1. State the characteristic features of living organisms. Which

characteristic feature is less conspicuous in plants ?Ans. 1. Living organisms are made up of cells.

2. They need nutrition.3. They grow and develop up to certain limits.4. They receive stimuli from the environment and respond to the same.5. They reproduce.6. They show structural and functional organization.7. They show ability to adapt to changes in their environment.Out of these features, showing the ability to adapt to the changes in theirenvironment is less conspicuous in plants.

2. How do we taste food ?Ans. 1. There are distinct regions on the tongue where main tastes are detected

or recognized.2. Taste buds at the tip of the tongue detect sweet tastes, those at the

back detect bitter tastes and those at the side of the tongue detectsalty and sour tastes.

3. The taste buds on the tongue transmit the different taste informationas a message to the brain.

4. Brain processes the information and tells us what food is actually inour mouth.


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3. How do we smell ?Ans. 1. Smells enter the back of the nose when you inhale. They also rise up

from the back of the mouth as we eat, which is why smell is such animportant part of tasting and enjoying food.

2. This is the reason why food tastes odd when we have a cold as thenasal organs become inflamed and the sense of smell is temporarilysmothered.

4. How does our memory work ?Ans. 1. Sensory memory is brief, it tells us what is happening around us.

2. Short term memory lasts only for 30 seconds. Eg. We remember aphone number and dial it and then it vanishes.

3. Long term memory is for the things that we have carefully learned andmemorized.

*5. Classify the following as voluntary and involuntary movements.1. Coughing 2. Food getting digested3. Moving a table 4. Kicking a ball5. Beating of heart 6. Release of hormones into blood7. Flying a kite.

Ans. 1. Coughing – Involuntary2. Food getting digested – Involuntary3. Moving a table – Voluntary4. Kicking a ball – Voluntary5. Beating of heart – Involuntary6. Release of hormones into blood – Involuntary7. Flying a kite – Voluntary.

6. Give examples of growth independent movements in plants.Ans. 1. Closing of leaflets of mimosa plant when touched.

2. Opening of lotus in the morning and tuberose at night.3. Insectivorous plants like drosera curl inwards at the touch of an insect

and trap the insect.4. The explosive fruit of balsam plant bursts open at an appropriate time

thus scattering the seeds.7. How does the Venus flytrap traps insects ?

Ans. 1. The Venus flytrap has a trap which looks an smells like a flower to insects.2. When insects land on it, they touch a trigger hair which slams the trap

shut and they are then digested by the plant.8. How are neurons classified ? State their functions.

Ans. 1. Neurons are of three types i.e. sensory neuron, motor neuron andassociation neuron.

2. Sensory neurons conduct impulses from the sense organs to the brainand spinal cord.

3. Motor neurons conduct impulses from the brain and spinal cord to theeffector organs like muscles and glands.

4. Association neurons perform integrative functions of the nervous system.9. How are nerves categorized based on their functions ?

Ans. 1. On the basis of their functions, the nerves are categorized as afferentnerves and efferent nerves.

2. Afferent nerves carry impulses from the sensory organs to the brain.3. Efferent nerves carry impulses from the brain to the sensory organs.

Q.III (C) Write short notes for the following :*1. Reflex action.

Ans. 1. Any sudden change in response to some happening in the environment,is called as reflex action.


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2. We react to such a situation without thinking about it or without feelingin control of our reactions.

3. Example : When we touch a vessel containing very hot tea, immediatelythe hand is withdrawn.

4. In this case, the nerves that detect pain are connected to the nervesthat bring about the action of the muscle, hence the action is completedquickly.

5. Nerves from all over the body meeting in a bundle in such a connectionis called as the spinal cord.

6. Hence reflex arcs are formed in the spinal cord, although the messagesreach the brain.

*2. Co-ordination in plants.Ans. 1. Plants do not have a nervous system or muscular system.

2. The movements exhibited by plants are mainly in response to thestimulus.

3. In certain sensitive plants like Mimosa, movement is in response tothe stimulus of touch. This movement is known as seismonasticmovement. There is no growth involved in this movement.

4. On the other hand, the movement of a seedling is because of growth. Ifgrowth is prevented, it does not exhibit any movement.

5. Thus, we conclude that plants exhibit two types of movement, one whichis growth dependent movement and the other which is growthindependent movement.

Q.IV (A) Distinguish between :*1. Voluntary movements and Involuntary movements.

Ans.

2. Growth dependent movements and Growth independent movements.Ans. Growth dependent movements

1. Growth dependent movementsresult in growth of the plants.

2. Growth dependent movementsare also called as tropicmovements.

3. Growth dependent movementsare in response to the stimulusof light, water, gravity etc.

4. Eg. Bending of stem towardslight, movement of roots towardsgravity and water.

Growth independent movements

1. Growth independent movementsdo not result in growth of theplants.

2. Growth independent movementsare also known as nasticmovements.

3. Growth independent movementsare in response to the stimulusof touch.

4. Eg. Closing of leaflets in mimosaplant, shutting of Venus flytrap.

Voluntary movements

1. Movements which are under ourcontrol are called voluntarymovements.

2. Voluntary movements requirethinking.

3. Voluntary movements arecontrolled by cerebellum.

4. Eg. Moving a table, kicking a ball,walking, clapping hands etc.

Involuntary movements

1. Movements which are not underour control are called involuntarymovements.

2. Involuntary movements do notrequire thinking.

3. Involuntary movements arecontrolled by midbrain andhindbrain.

4. Eg. Blood flow, breathing,sneezing etc.


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3. Central nervous system and Peripheral nervous system.Ans.

4. Cerebrum and Cerebellum.Ans.

Q.IV (B) Draw a neat and labelled diagram of the following :1. Human brain showing different areas and their responsibilities.

Ans.

2. V.S. of human brain.Ans.

Corpuscallosum

Pituitary gland

Pons varolii

Medulla oblongata

Cerebrum

Pineal body

Arbor vitae

Cerebellum

Central nervous system

1. Central nervous system iscomposed of brain and spinalcord.

2. Central nervous system islocated in the centre of the body.

Peripheral nervous system

1. Peripheral nervous system iscomposed of all the nerves.

2. Peripheral nerves are spreadthroughout the body.

Cerebrum

1. Cerebrum is the part of forebrain.

2. Cerebrum is responsible forthinking and interpretingsensory information.

Cerebellum

1. Cerebellum is the part ofhindbrain.

2. Cerebellum is responsible forcoordinating the voluntarymovements and also maintainingthe balance of the body.

Thought area

Movement areaTouch area

Hearing area

Vision area

Speed


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3. Neuron.Ans.

4. Neuromuscular junction.Ans.

5. Chemotropism (Growth of Pollen tube towards the ovules).Ans.

Pollen tube

Ovum(a) (b)

Pollen grain (germinating)

Zygote formation

Dendrites

Cyton (cell body)

Nucleus

Axon

Axon Neuromuscularjunction

Muscle fiber

Capillary Mitochondrion


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6. Reflex arc.Ans.

Q.V Answer the following in detail :1. What is co ordination ? Explain its importance.

Ans. 1. Co ordination means orderly execution of the activities, so that anorganism shows proper growth and development.

2. For example, man sees food, hand picks it up and puts it into themouth. The morsel of food is chewed in the mouth with the help ofteeth assisted by the tongue. The food is mixed with the enzymes inthe saliva secreted by salivary glands.

3. For further biochemical reactions, the food is sent to stomach and thecomplex food materials are broken down into simple forms such asglucose, amino acids and fatty acids.

4. The simple digested food is absorbed into blood through intestines andundigested food is excreted.

5. Thus digestion, absorption, circulation, excretion are interdependent.6. Oxygen is necessary to obtain energy from glucose and fatty acid.

Oxygen is supplied by the process of respiration.7. Thus, various organ systems function in a synchronized manner. Co-

ordination is necessary between organs and organ systems that bringabout all the inter-related life processes.

8. Any disturbance at any stage due to lack of co-ordination can leave thedesired process incomplete.

9. Thus for successful completion of desired process, there has to be perfectco ordination between different systems and / or organs involved atevery step.

2. What is homoeostasis ? How is it maintained in an individual’s body ?Ans. 1. The maintenance of the steady state by different systems of an organism

for its optimal functioning because of a perfect co ordination is calledhomoeostasis.

2. Control and co ordination provide stability and maintenance of the steadystate i.e. creation of a relatively constant environmental condition withinany organism.

3. In an individual’s body perfect co ordination between internal activitiesof the body caused due to water or enzyme level and temperature etc.and similar such external environmental stimuli must be there toachieve homoeostasis (e.g. In summer, with excessive sweating wefeel more thirsty.)

4. In animals, nervous system along with hormones bring about coordination.

5. In plants, due to lack of nervous system only hormones bring aboutchemical co ordination.

Spinal chord (CNS)Messageto brain

Relay neuron

Motorneuron

Effector-muscle in arm

Sensory neuron

Receptors-heat painReceptors in skin


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3. What is tropic movement ? Describe the different types of tropicmovements.

Ans. The movement or growth of any part of a plant in response to an externalstimulus is called tropism or tropic movement.Tropic movements are of three types :1. Phototropic movement (Phototropism) : The movement of a plant in

response to the stimulus of light is called phototropism. E.g. the shootsystem of any plant responds towards the stimulus of light i.e. it growsin the direction of source of light.

2. Gravitropic movement (Gravitropism) : The root system of the plantsresponds to the stimulus of gravity. This movement is called asgravitropic movement.

*3. Hydrotropic movement (Hydrotropism) : The root system of the plantsresponds to the stimulus of water. This movement is called hydrotropicmovement.

4. Chemotropic movement (Chemotropism) : It is the movement of aplant part in response to certain chemicals. E.g. the growth of pollentube towards the ovules.

4. Which are the different parts of the human nervous system?Ans. The human nervous system can be divided into :

1. The Central Nervous System (CNS) : It comprises of the brain andspinal cord and regulates all activities of the body.

2. The Peripheral Nervous System (PNS) : It includes all the nerves. Thenerves form a network and spread throughout the body. They areinstrumental in connecting all parts of the body to the central nervoussystem.

3. The Autonomic Nervous Sytem (ANS) : If comprises of all the nervespresent in the involuntary organs like heart, stomach, lungs etc.

4. On the basis of their function, the nerves are categorized as afferentand efferent nerves.

5. The nerves are composed of neurons and neuroglia. The neurons arespecialized cells capable of creating and transmitting electrochemicalimpulses. The neuroglia are supportive cells which assist the neuronsin their function.

5. Describe the Central Nervous System in human beings.Ans. 1. The central Nervous system is a delicate structure composed of the

brain and spinal cord.2. The brain is protected by a bony structure called cranium or skull and

the spinal cord is protected by the vertebral column or the back bone.3. In between the soft CNS and the bone are present protective membranes

called the meninges.4. There are cavities present on the different parts of brain known as

ventricles, while the long cavity of the spinal cord is called centralcanal.

5. The ventricles, central canal and the space between the meninges arefilled with cerebrospinal fluid (CSF).

6. The CSF keeps the CNS well nourished and also protects it fromabsorbing mechanical shocks.

7. The brain is a complex organ divided into three regions : the forebrain,midbrain and hindbrain.

8. The forebrain or cerebrum is the main thinking part of the brain. It hasregions which receive the sensory impulses from various receptors.The areas for smell, hearing, vision etc. are separate.


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9. Even there are different areas where the sensory information is receivedand interpreted and put together with the information received fromother receptors as well as the information that is already stored in thebrain. Such centres are known as association centres.

10. Involuntary activities like blood flow, breathing, sneezing etc. arecontrolled by Medulla oblongata, a component of the hind brain.

11. Another component of the hind brain is cerebellum. It is responsiblefor co-ordinating the voluntary movements and also maintaining thebalance of our body. Eg. riding a bicycle, picking up an object from thefloor, running along a straight line etc.

12. Spinal cord is an important part of the CNS which extends through thevertebral column. It controls the reflex actions.

13. Each side of our brain controls the opposite side of the body. Usuallythe left side of the brain controls speaking, writing and logical thought.The right side of the brain controls artistic abilities.

*6. Describe chemical co ordination in animals.Ans. 1. The chemical control is brought about by chemical substances called

hormones.2. These hormones are secreted by endocrine glands also known as the

ductless glands.3. On production these hormones are directly released into the blood

stream, due to this the hormones reach every where in the body thoughthe gland secreting them is located in a particular place.

4. The endocrine system shares its responsibility of control and coordination with the nervous system. Both systems work in co-operationto integrate and control various body activities.

5. The significant difference between the two systems is that the nerveimpulses are rapid and are usually of short duration while the hormonalaction is much slower and longlasting.

6. Eg. Suppose some animal like rabbit is caught in a scary situation, itsbody has to be prepared either to fight with the situation or to run awayfrom there. Both are extremely complicated activities that will utilize agreat deal of energy in controlled ways.

7. If the body of the rabbit has to trust only the electrical impulses throughnerve cells, then the tissues instructed to get prepared for the activitywould be limited. On the other hand, if chemical signals were to besent, it would reach each and every cell of the body and render a widerange of changes that are needed.

8. In chemical co-ordination, the hormones are secreted according to therequirement. The required quantity of hormone released and the timeof release is regulated by feedback mechanisms.Example : When the sugar level of blood rises, it is detected by thecells of the pancreas which respond to the situation by producing moreinsulin. As the sugar level of the blood falls, the secretion of insulin isreduced.

7. Describe the conduction of nerve impulse.Ans. 1. Nerves are composed of neurons and neuroglia. The neurons are

specialized cells capable of creating and transmitting electrochemicalimpulses.

2. All the information from our environment is picked up by the specializedtips of dendrites of a neuron.

3. This sets off a chemical reaction producing an electrical impulse whichtravels from dendrite to cell body, from there through the axon (nervefibre) to its end.


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4. At the end of the first axon, the electrical impulse induces release ofsome chemicals.

5. These chemicals produced go across the small gap (synapse) of 2 -20nm between the neurons and start a similar electrical impulse inthe dendrite of the next neuron.

6. The impulses travel in body in the above manner from the neurons andare delivered to the muscle cell or glands.

7. When an action or movement has to be brought about, the muscletissue does the final job. Muscle cells possess special kinds of proteinswhich are capable of bringing about change in their shape and makethe cell capable to respond to the nervous electrical impulses.

8. Describe the movements in plants which are growth independent.Ans. 1. Certain movements of plants do not result in their growth and are

termed as growth independent movements.2. Hormones bring about various movements in plants in response to the

changes occuring in their surroundings.3. These movements also happen at a place different from the place of

touch. This means that the information that a touch has occured hasbeen communicated. Eg. Closing of leaflets of Mimosa on touch.

4. Plants use electrochemical means to transfer information from cell toanother as there is no specialized tissue for the conduction ofinformation.

5. Then the movement is brought about as the plant cells change theirshapes by altering the amount of water in them. By this the cellseither swell or shrink and thus change their shape.

6. Some other movements seen in plants which are growth independentare - lotus opens in the morning and the tube rose opens at night, thetentacles on the leaves of the insectivorous plants like Drosera curlinwards at the touch of an insect and trap the insect, the explosivefruit of balsam plant bursts open at appropriate time thus scatteringthe seeds.

7. The Venus flytrap which looks and smells like a flower to insects.When they land on it they touch a trigger hair which slams the trapshut and they digested by the plant.

9. Describe the growth dependent movements in plants.Ans. 1. The movement or growth of any part of a plant in response to an external

stimulus is called tropism or tropic movements.2. The shoot system of any plant responds towards the stimulus of light

i.e., it grows in the direction of source of light. When a potted plant iskept near the window in a room, the stem bends slightly towards thewindow. This movement exhibited by the plant is called phototropicmovement.

3. When light falls on a part of growing plant, a hormone called auxinwhich is synthesized at the tip of the shoot helps the cells to growlonger. As the light is falling on one side of the plant, this hormoneauxin diffuses towards the shady side of the shoot and stimulates thecells to grow longer.

4. On the other hand, the root system of the plants responds to the stimulusof gravity and water. These responses are called gravitropic andhydrotropic movements respectively.

5. The movement of plant part in response to certain chemicals.Eg. The growth of pollen tubes towards the ovules.


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Q.VI Answer the following questions in one sentence each :1. Name the sense organs.

Ans. The sense organs are eyes, nose, ears, tongue, skin.2. Where do you find the gustatory and olfactory receptors ?

Ans. Gustatory receptors are located on the tongue and olfactory receptors arelocated in the nose.

3. What do the gustatory and olfactory receptors detect ?Ans. Gustatory receptors detect tastes and olfactory receptors detect smell.

4. How are life processes controlled in unicellular amoeba ?Ans. In unicellular amoeba, there is no nervous system. The cell is sensitive

enough to control its own life processes or activities.5. How is the nerve cord formed in annelidans like earthworm ?

Ans. In annelidans like earthworm a number of nerve cells come together andform a cluster. These clusters are joined together to form a beaded structurecalled the nerve cord.

6. What is short term memory ?Ans. Short term memory lasts only for 30 seconds. Eg. Remember a phone

number and dial it and then it vanishes from memory.7. What is long term memory ?

Ans. Long term memory is the memory for things that we have carefully learnedand memorized.

8. What is a neuron ?Ans. Neuron is a specialized cell capable of creating and transmitting

electrochemical impulses.9. What is the function of hormones in arthropods ?

Ans. In arthropods, hormones induce colour changes and are influential inregulating development.


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ACTIVITY BASED QUESTIONS

ACTIVITY : 11.1

Q. Take out from the refrigerator the polyethylene bag in which vegetablesare kept. After 5 minutes, remove the vegetables from the bag and feelthe inside of the bag. What is your observation ?

Ans. The inside of the bag feels moist. This is due to loss of water from thevegetables. This loss of water is called transpiration.

ACTIVITY : 11.2

• Take a shallow bottle with a wide mouth.• Put some moist cotton in it.• Place a few sprouted seeds on it.

Q. Observe the directions of growth of radicle and plumule.Ans. The radicle grows downwards and the plumule grows upwards.

• Pick up one of the sprouts and place it in such a way that the radicle istowards the source of light and the plumule is away from light.

Q. Observe the directions of growth daily.Ans. The radicle bends downwards and the plumule bends towards light.

Q. What do you conclude from your observations ?Ans. The radicle is the part which forms roots so it bends downwards towards

the stimulus of gravity and water whereas the plumule is the part whichforms the stem so it bends towards the source of light.

ACTIVITY : 11.3

• Look for Mimosa plants in the garden or along the hedges. Touch theleaves of this plant.

Q. What do you observe ? What happens to them ?Ans. The leaflets of Mimosa plant fold and droop down.

Q. After half an hour, observe the same plant. Note down you observation.Ans. The leaflets again unfold and return to their normal position.

ACTIVITY : 11.4

Q. An inter-house Basketball match is in progress at your school’s court.List a few actions of the players where you observe control and co-ordination in their movements.

Ans. Control and co-ordination is observed in dodging the ball, jumping, running,passing it to the team mate and dribbling the ball.

ACTIVITY : 11.5

Q. Your pet dog Dollar is comfortably taking a nap. Go near him and drop astainless steel spoon on the floor. What do you observe ?

Ans. The dog startles and wakes up and his ear pinnae are raised.


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ACTIVITY : 11.6

Q. List the endocrine glands present in human beings. Where are theypositioned in our body ? Consult books in the library to find out abouttheir functions.

Ans.

Location

Brain

Base offorebrain

Lower part of theneck

A pair of capshaped organsabove eachkidney

In the curve ofthe smallintestine

Lie on thelateral walls ofthe pelvis

In the scrotum

Near the centerof the brain,between the twohemispheres

Behind thesternum andabove thetrachea andheart

Hormones

Releasinghormones

Growthhormones

Trophichormones

Prolactin

Vasopressin

Oxytocin

Thyroxine

AdrenalineandCortisone

Insulin andglucagon

OestrogenandProgesterone

Testosterone

Melatonin

Thymosin

Endocrineglands

Hypothalamus

Pituitary(Master gland)

Thyroid

Adrenal

Pancreas

Ovary(In females)

Testis(In males)

Pineal

Thymus

Functions

Regulation of the secretion ofhormones from the pituitary gland.

Development of bones and tissues.

Regulation of the secretion ofhormones from other endocrineglands.

Regulation of the function ofmammary glands.

Regulation of water and electrolytebalance.

Stimulates contractions of smoothmuscles, helps in child birth andlactation.

Regulates rate of growth andmetabolism.

Regulation of blood pressure, heartrate. Carbohydrate metabolism andmineral balance.

Regulates sugar metabolism.

Development of secondary sexualcharacters. Eg. Development ofbreasts in female. Regulation ofmenstrual cycle.

Development of secondary sexualcharacters in male. (Masculinefeatures such as growth ofmoustaches and beard.)

Its regulates the wake/sleeppatterns and seasonal functions.

It stimulates the activity of the T-lymphocytes which are responsiblefor invading organisms and killingthem.

Sr.No.

1.

2.

3.

4.

5.

6.

7.

8.

9.


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HOTS QUESTIONS & ANSWERS

1. The plant which has fruits is seen bending towards sunlight. Thisresponse of the plant to light is because of a hormone which is responsiblefor ...(a) helping the cells of the shoot to grow longer.(b) helping the cells of the fruit to divide.(c) helping the inhibition of growth of the part of the plant which is

directly in contact with the sunlight.Ans. Helping the cells of the shoot to grow longer.

2. State whether afferent or efferent nerves would be responsible forpassing the impulses between the brain and sensory organs or musclesor other body organs.(a) My finger got burnt while cooking.(b) The wild life photographer started running after the lion suddenly

jumped before him from nowhere.Ans. (a) Afferent nerve carried the impulse from finger to the brain.

(b) Efferent nerve carried the impulse from brain to the muscles of theleg.

3. In some of the plants, as a response to a stimulus, a small part of aplant such as a leaf, alters its shape. Explain.

Ans. Various stimuli such as touch or an insect make some of the plants respondby altering its shape. The information about the stimulus is passed onfrom one cell to another with the help of electrical or chemical means.Then, the alteration in shape or movement is brought about by changingthe amount of water inside the cells i.e. either by swelling or shrinking,thus changing the shape. Hormones are mainly responsible cause for thesemovements in the plant as a response to the stimuli.

4. Look at the following actions. Write the name of that part of the brainwhich controls them.(a) Riding a bicycle (b) Sneezing(c) Thinking (d) Speaking(e) Artistic abilities.

Ans. (a) Hind brain – Cerebellum.(b) Hind brain – Medulla oblongata.(c) Fore brain – Cerebellum.(d) Left part of the brain.(e) Right part of the brain.

5. Classify the following actions into voluntary and involuntary.(a) Mr. Ajay’s blood pressure shot up after a fight with his neighbour.(b) Shantanu was forced by his friends to tell a lie.

Ans. (a) Involuntary.(b) Voluntary.


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6. The following statement is false. What is the truth ? Why ?In human beings, in order to facilitate the secretion of hormones,endocrine glands are placed in ducts.

Ans. Endocrine glands are ductlesss glands. They are also called as ‘glands ofsecretion’. The hormone is secreted directly into the blood stream. Thisprovision is made to facilitate the transport of hormone to all the parts ofthe body in order to activate necessary body organs in a short duration.The hormone secreted is called as ‘chemical messenger’.

7. Evaluate the following situations and state if the movements werecontrolled by central and peripheral nervous system or autonomousnervous system :(a) Ram bent down to pick up his books on the floor.(b) My heart started beating very rapidly.(c) He blinked when he had to face a sudden flash of light.(d) Shyam was flying kite.(e) Seema’s stomach was upset after eating stale food.

Ans. (a) Central and peripheral nervous system.(b) Autonomous nervous system.(c) Autonomous nervous system.(d) Central and peripheral nervous system.(e) Autonomous nervous system.

8. Imagine that you are given powers to bring out changes in the systemof plants. What should be done to ...(a) stop the growth of the root towards water ?(b) expedite the process of cell division ?

Ans. (a) Remove the hormone auxin which is responsible for the growth andinduce Abscissic acid which inhibits the growth of a plant.

(b) Induce the hormone cytokinins which promotes the cell division.

9. Give three names of animals in accordance with the advancement oftheir nervous system. Justify.

Ans. (a) Amoeba. There is no nervous system at all. The cell carries out all thefunctions.

(b) Any member of the family of annelids in which a number of nerve cellscome together to form a cluster called nerve cord. (E.g. Earthworm)

(c) Human beings in which a well developed nervous system is presentconsisting of CNS (Central nervous system), PNS (Peripheral nervoussystem), ANS (Autonomous nervous system).

10. What would happen if ...(a) leaves a plant are coated with paint.(b) animals loose the capacity of reflex action.(c) plants lack Abscissic acid.(d) peripheral and autonomous nervous systems are detached from each

other and from Central nervous system.


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(e) there appears malfunctioning in the mid and hind brain whichcontrols involuntary action in the body of animals.

Ans. (a) The stomata would get blocked. Transpiration of water and gases wouldnot happen resulting into death of the plant.

(b) They would not be able to defend themselves from emergencies resultinginto injury or death.

(c) Abscissic acid is a hormone responsible for inhibiting growth of theplant. The plants would grow limitlessly. The leaves would not wilt.

(d) There would not be any co-ordination in the body of the animals andtheir existence would be impossible.

(e) The heart would stop as its beating is an involuntary action. Theanimals would be dead.

11. The movement of a plant organ in response to the stimulus of contact iscalled thigmotropism. It is seen in plants which climb by means of tendrilswhich are sensitive to the contact stimulus. Tendrils are found in plantslike Cucurbita and grapevine. Only the apical part of the tendril is sensitiveto contact.Questions :(a) What is thigmotropism ?(b) Which plants show thigmotropism ?(c) Give the names of any two plants which show tendrils.(d) Which part of the tendril is sensitive to contact ?

Ans. (a) The movement of a plant organ in response to the stimulus of contactis called thigmotropism.

(b) Thigmotropism is seen in plants which climb by means of tendrils.(c) Plants such as Cucurbita and grapevine show tendrils.(d) The apical part of the tendril is sensitive to contact.

12. Name the plant hormone :(a) Which inhibits growth and causes wilting of leaves ?(b) Which promotes cell division ?

Ans. (a) Abscissic acid.(b) Cytokinins.


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is is controlled by

Found in Found in

helps in

MovementMovement

Growthdependent

Growthindependent Nerves Chemicals

hormones fromlead to

Endocrine glands

BrainSpinal cord

comprises of

Hind brainMid brainForebraincontrols

VoluntaryAction

InvoluntaryAction

ReflexAction

sometimes influencethe action of

responsiblefor

Plants Animals

CONCEPT MAP

Control and Co-ordination

Q.I [A] Fill in the blanks : 21. ..................... do not possess a nervous system.2. Response to the stimulus of touch is called ..................... whereas

response to the stimulus of chemicals is called as ..................... .3. Brain is the main ..................... centre of the body.4. The loss of water from the plants is known as ..................... .

Q.I [B] Match the columns : 2Column A Column B

1. Gibberellins (a) Promoting cell division in fruits andseeds

2. Cytokinins (b) Tip of shoot to grow longer3. Abscissic acid (c) Promoting growth of stem4. Auxins (d) Wilting of leaves

Q.I [C] Name the following : 31. Maintenance of steady state by different systems in an organism.2. Cells those assist the neurons in their function.3. The small gap between the consecutive neurons.

Q.II Give scientific reasons : (Any Two) 41. Roots of plants go away from light.2. Hormones secreted by the endocrine glands are present everywhere

in the body.3. Insulin plays an important role in controlling the sugar level of blood.

Q.III Answer the following questions : (Any Two) 41. Write a note on Reflex action.2. Write a note on Co-ordination in plants.3. Distinguish between Voluntary and Involuntary movements.4. What is tropic movement ? Describe the different types of tropic

movements.

Q.IV Answer the following : (Any One) 51. Describe chemical co-ordination in animals.2. Describe the conduction of nerve impulse.

CHAPTER 11 : REGULATORS OF LIFE

S.S.C.

SCIENCE

Marks : 20

Duration : 1 hr.

Best Of Luck

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11. The Regulators of Life - .::Login Page::.mt-iconnect.com/MTE_Content/MTE/Notes_Question Paper/X...Transpiration takes place in the leaves through stomatal openings. Ans. True