CBSE Class 10 Science Control and coordination Sure Shot Questions Set 01

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CONTROL AND COORDNATION

 

ASSIGNMENT QUESTIONS SET - 1
CHAPTER - 7
CONTROL AND COORDINATION

 

1. What is a neuron? [1 Mark]

Answer:
1. A neuron is the structural and functional unit of the nervous system.
2. It is a specialized cell designed to transmit nerve impulses across the body.

Teacher's Note:
a) Neurons consist of a cell body (cyton), dendrites, and an axon.
b) They transmit information via electrical and chemical signals.

 

2. Name any two types of tropism. [1 Mark]

Answer:
1. Phototropism (movement in response to light).
2. Geotropism (movement in response to gravity).

Teacher's Note:
a) Tropisms are directional growth movements in plants.
b) Other valid examples include hydrotropism and chemotropism.

 

3. What is a phytohormone? Name any two phytohormones. [2 Marks]

Answer:
1. Phytohormones are naturally occurring organic substances synthesized in plant parts that regulate cellular activities, growth, and development.
2. Two examples are Auxin and Gibberellin.

Teacher's Note:
a) They are also known as plant growth regulators.
b) Mention both the definition and two clear examples to secure full marks.

 

4. Mention the receptors for light and sound in animals. [1 Mark]

Answer:
1. Photoreceptors are the receptors for light.
2. Phonoreceptors (or mechanoreceptors) are the receptors for sound.

Teacher's Note:
a) Photoreceptors are located in the eyes.
b) Phonoreceptors are located in the inner ear.

 

5. How does control and coordination takes place in plants? [3 Marks]

Answer:
1. Plants lack a nervous system and muscular tissue.
2. They coordinate their behavior and responses using chemical molecules known as phytohormones.
3. Plants also show tropic movements using electrical-chemical signals to transmit information from cell to cell.

Teacher's Note:
a) Highlight the absence of a nervous system in plants.
b) Distinguish clearly between growth-dependent movements and immediate responses.

 

6. Mention the names of various phytohormones. [2 Marks]

Answer:
1. Auxins
2. Gibberellins
3. Cytokinins
4. Abscisic acid

Teacher's Note:
a) Auxins, gibberellins, and cytokinins generally promote growth.
b) Abscisic acid typically inhibits growth and promotes dormancy or wilting.

 

7. Discuss phototropism. [2 Marks]

Answer:
1. Phototropism is the directional growth movement of a plant part in response to light.
2. The shoot system generally exhibits positive phototropism by bending towards the light source, while roots show negative phototropism.

Answer:

S.No.	Tropic Movements	Nastic Movements
1	These are directional growth movements.	These are non-directional movements.
2	The direction of response is determined by the direction of the stimulus.	The direction of response is independent of the direction of the stimulus.
3	These are slow growth-dependent movements.	These are often rapid movements not primarily based on growth.

Teacher's Note:
a) Use a tabular format for clear differentiation.
b) Emphasize the directional nature versus non-directional nature.
c) Mention speed and growth dependence as core differentiating factors.

 

9. Draw the diagram of a neuron. [2 Marks]

Answer:
1. A standard diagram of a neuron showing dendrites, cell body (cyton), nucleus, axon, myelin sheath, and axon terminals should be drawn.
2. Proper labeling of all parts is essential.

[Figure: Diagram of a neuron showing dendrites attached to a star-shaped cell body containing a nucleus, extending into a long axon wrapped in a myelin sheath, and ending in axon terminals.]

Teacher's Note:
a) Clear and neat labeling carries half the credit.
b) Ensure arrows point precisely to dendrites, cell body, axon, and nerve endings.

 

10. Draw a neat diagram of the nervous system in an insect. [3 Marks]

Answer:
1. The insect nervous system consists of a brain, a ventral nerve cord, and segmental ganglia.
2. A clear diagram illustrating these segmented ganglionic chains connected to the brain must be presented.

[Figure: Diagram of an insect nervous system showing a dorsal brain, circum-oesophageal connectives, and a double ventral nerve cord with segmental ganglia.]

Teacher's Note:
a) Insects possess a decentralized ladder-like ventral nerve cord.
b) Focus on labeling the brain and segmental ganglia correctly.

 

11. Describe the central nervous system in human beings. [3 Marks]

Answer:
1. The central nervous system (CNS) in human beings consists of the brain and the spinal cord.
2. The brain is the main coordinating center protected inside the skull (cranium) and is divided into forebrain, midbrain, and hindbrain.
3. The spinal cord originates from the medulla oblongata, runs down through the vertebral column, and handles reflex actions as well as communication between the brain and the body.

Teacher's Note:
a) State clearly that CNS comprises both the brain and the spinal cord.
b) Briefly outline the protective coverings like cranium and vertebral column.
c) Mention the primary functions of both components.

 

12. Write the functions of any one part of the hind - brain. [2 Marks]

Answer:
1. Cerebellum is a part of the hindbrain.
2. It is responsible for maintaining posture and balance of the body and coordinating precise voluntary muscle movements.

Teacher's Note:
a) Other parts of the hindbrain include the pons and medulla oblongata.
b) Medulla controls involuntary actions like blood pressure, salivation, and vomiting.

 

13. What is the autonomic nervous system? [2 Marks]

Answer:
1. The autonomic nervous system (ANS) is a component of the peripheral nervous system.
2. It regulates involuntary actions of internal organs, smooth muscles, and glands without conscious control.

Teacher's Note:
a) It is further divided into the sympathetic and parasympathetic nervous systems.
b) Examples of functions include heart rate regulation and digestion.

 

14. Define reflex action with suitable examples. [3 Marks]

Answer:
1. A reflex action is a sudden, rapid, involuntary, and automatic response of the body to a stimulus, controlled primarily by the spinal cord.
2. Example 1: Immediate withdrawal of the hand upon touching a hot object.
3. Example 2: Blinking of eyes when a bright light flashes or an object suddenly approaches.

Teacher's Note:
a) Define reflex action accurately highlighting its involuntary nature.
b) Provide at least two common everyday examples.
c) Mention the reflex arc as the pathway taken by nerve impulses during a reflex action.

 

15. Name the hormones secreted by thyroid, parathyroid and pancreas. Reaction of stimuli is a characteristic property of living organisms. Explain [4 Marks]

Answer:
1. The thyroid gland secretes thyroxine hormone.
2. The parathyroid gland secretes parathyroid hormone (parathormone).
3. The pancreas secretes insulin and glucagon.
4. Living organisms respond to changes in their environment (stimuli) such as light, heat, chemicals, or touch to adapt and survive, which is a fundamental characteristic of life.

Teacher's Note:
a) Ensure all three requested glands and their corresponding hormones are listed correctly.
b) Explain irritability or responsiveness as a core sign of living systems.
c) Mention coordination systems that enable these reactions in both plants and animals.

 

16. It usually takes lot of time to observe the effect of a stimulus on plants. Explain [2 Marks]

Answer:
1. Plant responses are primarily growth-dependent movements mediated by phytohormones.
2. Cell division and cell elongation take time, making the visible outcome of the stimulus slow compared to rapid animal reflex actions.

Teacher's Note:
a) Connect the slow response time to the absence of a nervous system.
b) Highlight the role of growth processes in tropic movements.

 

17. Why is control and coordination system necessary in organisms? [3 Marks]

Answer:
1. It helps multicellular organisms maintain internal stability and survive in changing external environments.
2. It ensures that various organs and systems work together harmoniously to perform vital life processes.
3. It protects the organism from harmful stimuli through coordinated responses like reflex actions.

Teacher's Note:
a) Emphasize survival and adaptation in changing environments.
b) Mention internal harmony and regulation among different organ systems.
c) Link control and coordination directly to homeostasis.

 

18. What is homeostasis? [2 Marks]

Answer:
1. Homeostasis is the ability of an organism to maintain a stable, relatively constant internal environment despite fluctuations in the external environment.
2. It is achieved through coordinated physiological and behavioral mechanisms.

Teacher's Note:
a) Mention internal stability and equilibrium.
b) Give examples like body temperature regulation or blood sugar levels.

 

19. Give examples of some of the movements shown by plants. [2 Marks]

Answer:
1. Phototropism (bending of shoots towards light).
2. Seismonastic movement (drooping of leaves of Mimosa pudica when touched).

Teacher's Note:
a) Include both growth movements (tropisms) and non-growth movements (nasties).
b) Mention hydrotropism or geotropism as alternative valid examples.

 

20. What are growth regulators? [2 Marks]

Answer:
1. Growth regulators are organic chemical substances synthesized by plants that regulate cellular growth, differentiation, and development.
2. They are commonly known as phytohormones.

Teacher's Note:
a) They can either promote or inhibit plant growth.
b) Mention auxins and gibberellins as standard examples.

 

21. What are the stages of growth in plants? [2 Marks]

Answer:
1. Cell division (formation of new cells).
2. Cell elongation (enlargement of newly formed cells) and cell differentiation (maturation into specialized tissues).

Teacher's Note:
a) Plant growth is localized in specific regions called meristems.
b) Distinguish between division, elongation, and differentiation stages.

 

22. Name the different phytohormones. [2 Marks]

Answer:
1. Auxins, gibberellins, and cytokinins (growth promoters).
2. Abscisic acid and ethylene (growth inhibitors or ripening agents).

Teacher's Note:
a) List at least four major plant hormones for complete credit.
b) Ethylene is gaseous and plays a key role in fruit ripening.

 

23. What are auxins? [2 Marks]

Answer:
1. Auxins are a class of plant hormones synthesized at the shoot tips.
2. They promote cell elongation and are primarily responsible for phototropic bending in plants.

Teacher's Note:
a) Indole-3-acetic acid (IAA) is the most common natural auxin.
b) Mention their role in cell enlargement and directional growth.

 

24. Give four major functions of auxins. [4 Marks]

Answer:
1. They promote cell elongation in stems and roots.
2. They regulate phototropic and geotropic responses by unequal distribution across plant organs.
3. They induce apical dominance, inhibiting the growth of lateral buds.
4. They promote root initiation on stem cuttings and prevent premature leaf and fruit fall.

Teacher's Note:
a) List four distinct, scientifically accurate functions.
b) Apical dominance is a crucial concept frequently tested in board examinations.
c) Mention root formation and prevention of abscission as key agricultural uses.

 

25. What are gibberellins and where are they synthesised? [2 Marks]

Answer:
1. Gibberellins are a group of plant hormones that help in growth, particularly in stem elongation and seed germination.
2. They are synthesised mainly in young tip regions of roots and leaves, developing seeds, and fruits.

Teacher's Note:
a) Gibberellins promote cell division and cell elongation in the internodal region.
b) They are naturally occurring phytohormones.

 

26. What is the most important commercial application of gibberellins? [1 Mark]

Answer:
1. The most important commercial application of gibberellins is to stimulate stem elongation in plants like grapes, sugarcane, and fruit crops to increase yield and fruit size.

Teacher's Note:
a) Gibberellins are widely sprayed on agricultural crops to enhance overall plant growth and length.

 

27. What are exocrine and endocrine glands? [2 Marks]

Answer:
1. Exocrine glands are glands that secrete their products through ducts directly onto epithelial surfaces or into body cavities.
2. Endocrine glands are ductless glands that release hormones directly into the bloodstream to target organs.

Teacher's Note:
a) Examples of exocrine glands include sweat glands and salivary glands.
b) Examples of endocrine glands include the thyroid gland and pituitary gland.

 

28. What are hormones? [1 Mark]

Answer:
1. Hormones are chemical messengers secreted by endocrine glands in very small amounts that coordinate various activities and growth of the body.

Teacher's Note:
a) They act directly on specific target organs and are transported via the blood.

 

29. What are the characteristics of hormones? [3 Marks]

Answer:
1. Hormones are secreted in very minute quantities by specific endocrine glands.
2. They are poured directly into the blood and transported to specific target organs.
3. They regulate various physiological processes and are destroyed after use, not stored in the body.

Teacher's Note:
a) Hormones act as chemical messengers in multicellular organisms.
b) Excess or deficiency of hormones can cause specific hormonal disorders.
c) They coordinate distant body parts unlike neural signals which use nerve impulses.

 

30. Name the various endocrine glands. [2 Marks]

Answer:
1. The major endocrine glands in the human body include the hypothalamus, pituitary gland, pineal gland, thyroid gland, and parathyroid glands.
2. Other important endocrine glands are the thymus, pancreas, adrenal glands, gonads (testis in males and ovary in females).

Teacher's Note:
a) The hypothalamus acts as a master control center linking the nervous and endocrine systems.
b) Endocrine glands secrete chemical messengers called hormones directly into blood.

 

31. What is TSH? Where is it produced? [2 Marks]

Answer:
1. TSH stands for Thyroid Stimulating Hormone, which stimulates the thyroid gland to secrete thyroxine.
2. It is produced and secreted by the anterior lobe of the pituitary gland.

Teacher's Note:
a) Pituitary gland is often called the master gland because it controls other endocrine glands.
b) TSH release is regulated by the hypothalamus.

 

32. Which gland has both exocrine and endocrine parts? [1 Mark]

Answer:
1. The pancreas acts as both an exocrine gland (secreting digestive enzymes through ducts) and an endocrine gland (secreting insulin and glucagon directly into the blood).

Teacher's Note:
a) The endocrine portion of the pancreas consists of clusters of cells called Islets of Langerhans.

 

33. Name the different regions of the brain and their parts. [2 Marks]

Answer:
1. Forebrain consists of the cerebrum, hypothalamus, and thalamus.
2. Midbrain and hindbrain consist of the cerebellum, pons, and medulla oblongata.

Teacher's Note:
a) The brain is the main coordinating center of the human body.
b) It is broadly divided into three main regions: forebrain, midbrain, and hindbrain.

 

34. What is cerebrum? What are its functions? [2 Marks]

Answer:
1. Cerebrum is the largest and main thinking part of the human brain located in the forebrain.
2. Its functions include controlling voluntary actions, reasoning, learning, memory, intelligence, and receiving sensory impulses.

Teacher's Note:
a) It is divided into left and right cerebral hemispheres.
b) Different regions of the cerebrum are specialized for hearing, sight, smell, and touch.

 

35. What is the importance of hypothalamus? [2 Marks]

Answer:
1. The hypothalamus regulates body temperature, urge for eating, and drinking (hunger and thirst centers).
2. It controls the secretions of the pituitary gland through releasing and inhibiting hormones.

Teacher's Note:
a) It is situated at the base of the cerebrum in the forebrain.
b) It serves as a vital link between the nervous and endocrine systems.

 

36. What are the functions of mid brain? [2 Marks]

Answer:
1. The midbrain controls reflex movements of the head, neck, and trunk in response to visual and auditory stimuli.
2. It also regulates reflex pupillary changes and changes in eye lens shape.

Teacher's Note:
a) It connects the forebrain to the hindbrain.
b) It helps process sensory information related to sight and sound.

 

37. What is cerebellum? Where is it present? What are its functions? [3 Marks]

Answer:
1. Cerebellum is a part of the hindbrain located at the base of the brain just below the cerebrum.
2. It maintains the posture and balance of the body during various activities.
3. It coordinates voluntary muscle movements ensuring smooth and precise actions like walking or riding a bicycle.

Teacher's Note:
a) Damage to the cerebellum results in loss of balance and uncoordinated body movements.
b) It is a prominent structure with folded surfaces to accommodate more neurons.
c) Unlike the cerebrum, it does not initiate voluntary actions but fine-tunes them.

 

38. What is the importance of medulla oblongata? [2 Marks]

Answer:
1. Medulla oblongata controls involuntary actions such as heartbeat, breathing, blood pressure, and peristalsis.
2. It also controls reflex actions like coughing, sneezing, salivation, and vomiting.

Teacher's Note:
a) It forms the lower part of the brainstem connecting to the spinal cord.
b) Injury to the medulla oblongata is usually fatal as it controls vital life-support functions.

 

39. What are the functions of spinal cord? [2 Marks]

Answer:
1. The spinal cord serves as the main pathway for conduction of sensory and motor messages between the brain and the rest of the body.
2. It is the center for spinal reflex actions which provide quick responses to sudden stimuli.

Teacher's Note:
a) It is enclosed and protected within the vertebral column (backbone).
b) It acts independently of the brain for rapid, automatic reflex arcs.

 

40. What is a reflex? [1 Mark]

Answer:
1. A reflex is an automatic, rapid, and involuntary response of the body to a stimulus that is controlled by the spinal cord without conscious involvement of the brain.

Teacher's Note:
a) Reflex actions protect the body from sudden potential harm or injury.

 

41. What are the two main types of reflexes? Give one example for each. [2 Marks]

Answer:
1. The two main types of reflexes are conditioned (acquired) reflexes and unconditioned (spinal/natural) reflexes.
2. Example of a conditioned reflex is salivation on seeing or smelling delicious food; example of an unconditioned reflex is the knee-jerk reflex or withdrawing the hand upon touching a hot object.

Teacher's Note:
a) Unconditioned reflexes are inborn and do not require prior experience.
b) Conditioned reflexes are acquired through learning and repeated practice.

 

42. What is a synapse? [1 Mark]

Answer:
1. A synapse is the functional junction between two adjacent neurons where nerve impulses are transmitted via chemical neurotransmitters from axon terminal to dendrite.

Teacher's Note:
a) Electrical signals convert into chemical signals at the synaptic cleft to cross over.

 

43. What are nerve fibres? [1 Mark]

Answer:
1. Nerve fibres are thread-like extensions of neurons (axons or dendrons) that transmit nerve impulses across different parts of the body.

Teacher's Note:
a) Bundles of nerve fibres bound together form a nerve.

 

44. What are nodes of Ranvier? [1 Mark]

Answer:
1. Nodes of Ranvier are periodic gaps in the myelin sheath along the axon of a neuron where the nerve fibre is exposed.

Teacher's Note:
a) They help speed up nerve impulse transmission through saltatory conduction.

 

45. What are the three types of nerves? [2 Marks]

Answer:
1. Sensory nerves, which carry impulses from receptors to the central nervous system.
2. Motor nerves, which carry impulses from the central nervous system to effectors, and mixed nerves, which perform both functions.

Teacher's Note:
a) Sensory neurons are also called afferent neurons.
b) Motor neurons are also called efferent neurons.

 

46. What are receptors? [1 Mark]

Answer:
1. Receptors are specialized cells or groups of receptor cells in sense organs that detect changes in the external or internal environment (stimuli).

Teacher's Note:
a) Examples include photoreceptors in eyes, thermoreceptors in skin, and gustatory receptors on the tongue.

 

47. What are effectors? [1 Mark]

Answer:
1. Effectors are muscles or glands that respond to nerve impulses received from the central nervous system to bring about an appropriate action.

Teacher's Note:
a) Muscles contract or relax, and glands secrete hormones in response to motor signals.

 

48. What is meningitis? [1 Mark]

Answer:
1. Meningitis is the inflammation of the meninges (protective membranes surrounding the brain and spinal cord), usually caused by bacterial or viral infection.

Teacher's Note:
a) It causes severe headache, fever, and stiffness in the neck.

 

49. What are the three divisions of the human nervous system? [1 Mark]

Answer:
1. Central Nervous System (CNS), Peripheral Nervous System (PNS), and Autonomous Nervous System (ANS).

Teacher's Note:
a) CNS includes the brain and spinal cord, while PNS includes cranial and spinal nerves.

 

50. What is the central nervous system composed of? [1 Mark]

Answer:
1. The central nervous system is composed of the brain and the spinal cord.

Teacher's Note:
a) It receives information from all parts of the body and integrates it.

 

51. How are organs of the central nervous system protected? [2 Marks]

Answer:
1. The brain is protected by a bony box called the cranium and enclosed within three protective membranes called meninges with cerebrospinal fluid cushioning it.
2. The spinal cord is protected by the bony vertebral column (backbone).

Teacher's Note:
a) Cerebrospinal fluid acts as a shock absorber protecting CNS from mechanical shocks.
b) Both brain and spinal cord are delicate organs requiring extensive skeletal protection.

 

52. Difference between dormancy and breaking of dormancy [3 Marks]

Answer:
1. Dormancy refers to a period of arrested plant growth where seeds or buds remain inactive under unfavorable conditions.
2. Breaking of dormancy is the resumption of active metabolic growth and germination when favorable conditions like temperature and moisture return.
3. Plant hormones such as abscisic acid maintain dormancy, while gibberellins play a major role in breaking dormancy.

Teacher's Note:
a) Dormancy is an evolutionary survival mechanism protecting plants from harsh environments.
b) Students often confuse dormancy with plant death; emphasize that it is a reversible state of suspended animation.
c) Mentioning specific hormones adds crucial precision for full marks.

 

53. Write Four major types of plant hormones and their functions [5 Marks]

Answer:
1. Auxin promotes cell elongation, stem growth, and phototropism.
2. Gibberellin stimulates stem elongation, seed germination, and flowering.
3. Cytokinin promotes cell division, delays leaf aging, and breaks seed dormancy.
4. Abscisic acid inhibits growth, promotes wilting of leaves, and induces dormancy.

Teacher's Note:
a) Plant hormones coordinate growth, development, and responses to environmental stimuli.
b) A common mistake is omitting abscisic acid, thinking all hormones promote growth.
c) State both growth promoters and growth inhibitors clearly.
d) Ethylene can also be mentioned as a gaseous plant hormone responsible for fruit ripening.

 

54. How does tropism helps in movement? [2 Marks]

Answer:
1. Tropism is a directional growth movement in plants in response to an external stimulus.
2. It helps plants grow toward beneficial stimuli like light and water or away from harmful conditions, ensuring survival.

Teacher's Note:
a) Tropisms are slow, growth-dependent directional movements.
b) Always distinguish tropism from immediate nastic movements.

 

55. Why does the stem of a plant bend to one direction? [2 Marks]

Answer:
1. When light falls on one side of a plant stem, auxin hormones diffuse toward the shady side.
2. Higher auxin concentration on the shady side causes cells there to elongate faster, bending the stem toward the light source.

Teacher's Note:
a) This differential growth is the core mechanism of phototropism.
b) Ensure students explain auxin redistribution clearly.

 

56. Explain the bending of plant root away from light by the action of auxin hormones [3 Marks]

Answer:
1. Roots exhibit negative phototropism by growing away from light.
2. Auxins accumulate on the darker side of the root due to light-induced lateral redistribution.
3. Unlike stems, high auxin concentrations inhibit cell elongation in roots, causing the illuminated side to grow faster and bend the root away from light.

Teacher's Note:
a) Root sensitivity to auxin is opposite to that of stem tissues.
b) A frequent error is assuming auxin promotes growth equally in all plant organs.
c) Emphasize that high auxin inhibits root cell elongation.

 

57. Give an example of chemotropism? With the help of diagram [3 Marks]

Answer:
1. The growth of a pollen tube towards the ovule during fertilization in a flower is a classic example of chemotropism.
2. This directional growth happens in response to chemical substances secreted by the ovule.
3.

[Figure: Diagram showing a pistil with pollen grain on stigma, and pollen tube growing down the style toward the ovule in the ovary]

Teacher's Note:
a) Chemotropism is directional growth driven by chemical stimuli.
b) Mentioning pollen tube growth is the standard textbook example.
c) Labeling the stigma, style, ovary, and pollen tube is essential in the diagram.

 

58. Roots can grow against the law of gravity. When does this happen? [2 Marks]

Answer:
1. Roots generally grow downward with gravity (positive geotropism).
2. However, pneumatophores or breathing roots in mangroves grow upward against gravity to obtain oxygen in waterlogged soils.

Teacher's Note:
a) Hydrotropism or chemotropism can also override geotropism under specific conditions.
b) Mangrove roots provide a prime biological exception to standard geotropic behavior.

 

59. Definition and Function of thigmotropism [3 Marks]

Answer:
1. Thigmotropism is the directional growth movement of a plant in response to touch or contact with a solid object.
2. The side of the tendril in contact with the support grows slower, while the opposite side grows faster.
3. This differential growth causes the tendril to coil around the support, providing structural support to weak-stemmed plants.

Teacher's Note:
a) Common in climbing plants and twiners.
b) Distinguish clearly between thigmotropism (growth movement) and thigmonasty (non-growth touch response like in Mimosa).

 

60. Why do followers open their petals in morning and close them in evening [2 Marks]

Answer:
1. Flowers open and close their petals in response to light or temperature changes through nastic movements like photonasty.
2. Differential growth or reversible turgor pressure changes in the cells of the petal cause this rhythmic daily movement.

Teacher's Note:
a) Note the paper's spelling typo 'followers' means flowers.
b) Nastic movements are non-directional responses to stimuli.

 

61. Name the Scientific terms for Bending of shoot towards sunlight [1 Mark]

Answer:
1. Positive phototropism.

Teacher's Note:
a) Always include the directional prefix positive or negative when naming scientific tropisms.

 

62. Name the Scientific terms for Growing of root towards the earth [1 Mark]

Answer:
1. Positive geotropism.

Teacher's Note:
a) Gravity is the stimulus, hence geotropism or gravitropism.

 

63. Name the Scientific terms for Growth of a pollen tube towards ovule [1 Mark]

Answer:
1. Chemotropism.

Teacher's Note:
a) Chemical gradients guide the directional growth here.

 

64. Name the Scientific terms for Bending of root towards water [1 Mark]

Answer:
1. Positive hydrotropism.

Teacher's Note:
a) Water availability acts as the directional stimulus.

 

65. Name the Scientific terms for Winding of tendril around a support [1 Mark]

Answer:
1. Thigmotropism.

Teacher's Note:
a) Touch or contact is the directional stimulus.

 

66. What is Receptor and write its role [2 Marks]

Answer:
1. A receptor is a specialized cell or a group of nerve cells located in sense organs that detect specific environmental stimuli.
2. Its role is to receive information from the surroundings and transmit the electrical signal to the sensory neuron.

Teacher's Note:
a) Receptors act as the starting point of nervous coordination.
b) Examples include photoreceptors in eyes and gustatory receptors on the tongue.

 

67. Explain the Function of Human nervous system [3 Marks]

Answer:
1. It receives sensory information from sense organs and internal receptors.
2. It processes, integrates, and analyzes this information to make appropriate decisions.
3. It transmits motor commands to effectors like muscles and glands to produce coordinated responses.

Teacher's Note:
a) The nervous system ensures rapid communication through electrical impulses.
b) It links environmental stimuli to body responses.
c) Mentioning the central and peripheral divisions enhances completeness.

 

68. Explain the function of electrical impulses [2 Marks]

Answer:
1. Electrical impulses transmit information rapidly along the length of a nerve cell from dendrites to axon terminals.
2. They allow quick communication and immediate reflex responses across the nervous system.

Teacher's Note:
a) Electrical impulses travel quickly but cannot reach every cell in the body.
b) Chemical signals bridge the gap at synapses.

 

69. Draw the diagram of neuron and explain its function [4 Marks]

Answer:
1.

[Figure: Diagram of a neuron showing dendrites, cell body, nucleus, axon, myelin sheath, and axon terminal]

2. Dendrites receive electrical signals from receptors or adjacent neurons.
3. The cell body processes information and passes it down the axon as an electrical impulse.
4. Axon terminals transmit the signal across synapses to the next target cell.

Teacher's Note:
a) The neuron is the structural and functional unit of the nervous system.
b) Labeling dendrites, cell body, and axon is mandatory for full marks.
c) Explain unidirectional impulse flow clearly.
d) Mentioning the myelin sheath adds extra technical accuracy.

 

70. How are messages transferred from one neuron to another? [2 Marks]

Answer:
1. When an electrical impulse reaches the axon terminal, it triggers the release of neurotransmitter chemicals.
2. These chemicals cross the synaptic cleft and start a new electrical impulse in the dendrite of the next neuron.

Teacher's Note:
a) Electrical signals convert to chemical signals at synapses.
b) This ensures unidirectional flow of nerve impulses.

 

71. Name the Gap between two neurons [1 Mark]

Answer:
1. Synapse (or synaptic cleft).

Teacher's Note:
a) The synapse acts as a chemical bridge between adjacent nerve cells.

 

72. Explain the types of peripheral nervous systemIn a reflex action, we are unaware that anything is going to happen to us. Explain [4 Marks]

Answer:
1. The peripheral nervous system consists of cranial nerves arising from the brain and spinal nerves arising from the spinal cord.
2. It includes the somatic nervous system controlling voluntary actions and the autonomic nervous system controlling involuntary functions.
3. In a reflex action, the sensory signal bypasses the conscious thinking areas of the brain and is processed directly by the spinal cord.
4. This rapid spinal pathway produces an instantaneous involuntary response before the brain registers the event, making us unaware until after it occurs.

Teacher's Note:
a) Note that the question text combines two separate concepts (PNS types and reflex awareness) into one.
b) Address both parts clearly to secure full marks.
c) Reflex actions ensure survival by saving processing time in dangerous situations.
d) The brain receives information about the reflex action after the response has already taken place.

 

73. Explain the Diagram of reflex arc with its details [4 Marks]

Answer:
1.

[Figure: Diagram of a reflex arc showing receptor in skin, sensory neuron, spinal cord with relay neuron, motor neuron, and effector muscle]

2. Receptor detects the stimulus and sends an electrical impulse via the sensory neuron to the spinal cord.
3. The relay neuron inside the central nervous system processes and transmits the signal to the motor neuron.
4. The motor neuron carries the command to the effector muscle, which contracts to produce the rapid response.

Teacher's Note:
a) A reflex arc is the shortest pathway taken by nerve impulses during a reflex action.
b) All five components (receptor, sensory neuron, integration center/relay neuron, motor neuron, effector) must be labeled.
c) Arrows must clearly indicate the direction of nerve impulse flow.
d) Emphasize that the spinal cord acts as the reflex processing center.

 

74. How effectors cause action [2 Marks]

Answer:
1. Effectors are muscles or glands that receive motor impulses from the nervous system.
2. Muscles contract by changing cellular protein shape in response to nerve signals, while glands secrete specific hormones or enzymes.

Teacher's Note:
a) Effectors execute the final response ordered by the nervous system.
b) Muscle tissue contraction involves specialized protein filaments.

 

75. What is Self governing nervous system and write its function [3 Marks]

Answer:
1. The self governing nervous system refers to the autonomic nervous system.
2. It regulates involuntary body functions such as heartbeat, digestion, respiration, and glandular secretion.
3. It operates independently of conscious control, maintaining internal body stability or homeostasis.

Teacher's Note:
a) Autonomic means self-governing.
b) Divided further into sympathetic and parasympathetic systems.
c) Essential for involuntary life-support processes.

 

76. What is the Functions of central nervous system? [3 Marks]

Answer:
1. It receives and integrates sensory inputs from all parts of the body.
2. It processes information, coordinates responses, and stores memory in the brain.
3. It controls reflex actions through the spinal cord for rapid protective responses.

Teacher's Note:
a) The central nervous system consists of the brain and spinal cord.
b) It acts as the primary control and command center of the body.
c) Crucial for both voluntary control and reflex integration.

 

77. Brain is the highest coordinating centre in the body. Explain [4 Marks]

Answer:
1. The brain receives sensory impulses from all receptors across the body and integrates this complex information.
2. It allows for conscious thinking, reasoning, learning, and memory storage.
3. It coordinates complex voluntary muscular actions through the cerebellum and cerebrum.
4. It regulates involuntary vital activities via the brainstem, ensuring overall body harmony and survival.

Teacher's Note:
a) The brain integrates inputs from multiple sources before sending commands.
b) Divided into forebrain, midbrain, and hindbrain with specialized functions.
c) Higher cognitive functions distinguish human neurological control.
d) Protected safely inside the bony cranium and cerebrospinal fluid.

 

78. Explain the Function of different part of brain. [5 Marks]

Answer:
1. Forebrain: It is the main thinking part of the brain and contains regions for hearing, smell, sight, and complex mental processes.
2. Cerebrum: Part of the forebrain that controls voluntary actions, memory, reasoning, intelligence, and receives sensory impulses.
3. Midbrain: Controls reflex movements of the head, neck, and trunk in response to visual and auditory stimuli.
4. Hindbrain: Consists of cerebellum, pons, and medulla oblongata, which regulate involuntary actions and posture.
5. Cerebellum, Medulla and Pons: Cerebellum maintains posture and balance; medulla controls involuntary activities like blood pressure, salivation, and vomiting.
6. Hypothalamus: Regulates body temperature, urge for eating, and drinking.

Teacher's Note:
a) The brain is broadly divided into forebrain, midbrain, and hindbrain.
b) Students must clearly distinguish between voluntary and involuntary functions.
c) Mentioning specific sub-parts like medulla and cerebellum ensures full credit.
d) Always link anatomical regions to their exact physiological roles.

 

79. How is all the voluntary action of body coordinated by cerebrum? [3 Marks]

Answer:
1. The cerebrum receives sensory impulses from various receptor organs across the body.
2. It processes this sensory information by interpreting it and matching it with past experiences.
3. It then sends motor impulses to the skeletal muscles to execute the desired voluntary physical action.

Teacher's Note:
a) Cerebrum is the seat of consciousness and voluntary control.
b) Motor neurons carry signals from the cerebrum to effectors.
c) Coordination involves sensory input, central processing, and motor output.

 

80. What is Animal hormones and write its functions [3 Marks]

Answer:
1. Animal hormones are chemical messengers secreted directly into the blood by endocrine glands to regulate physiological processes.
2. They help in coordinating body growth, development, and overall behavioral responses.
3. They maintain homeostasis by regulating metabolism, internal environment, and reproductive cycles.

Teacher's Note:
a) Hormones act as chemical messengers distinct from neural impulses.
b) They are transported via the circulatory system to target organs.
c) Mentioning target specificity is crucial for complete understanding.

 

81. Hormones are kind of chemical messengers. Explain [3 Marks]

Answer:
1. Endocrine glands synthesize and release hormones directly into the bloodstream in response to specific stimuli.
2. The blood carries these chemical substances to distant target organs or tissues in the body.
3. Upon reaching the target organ, they trigger specific metabolic changes or physiological responses.

Teacher's Note:
a) The analogy of a messenger highlights transport via blood to target cells.
b) Hormones regulate slow and long-lasting body responses.
c) Specific receptor sites on target cells receive these chemical messages.

 

82. Name all glands in our body having both exocrine and endocrine functions? [1 Mark]

Answer:
1. Pancreas is the primary gland in the human body having both exocrine and endocrine functions.

Teacher's Note:
a) Such glands are known as heterocrine or mixed glands.
b) Pancreas secretes digestive enzymes externally and hormones internally.

 

83. What is hormonal system? Position of endocrine glands in human body. [5 Marks]

Answer:
1. Hormonal system consists of various endocrine glands that secrete chemical messengers to coordinate body functions.
2. Hypothalamus, pituitary gland, and pineal gland are located in the brain.
3. Thyroid and parathyroid glands are situated in the neck region.
4. Thymus is located in the chest cavity near the heart.
5. Adrenal glands are positioned on top of both kidneys, and pancreas is located near the stomach.
6. Gonads (testes in males and ovaries in females) are located in the lower abdomen and pelvic region respectively.

Teacher's Note:
a) The endocrine system works alongside the nervous system for body control.
b) Anatomical positions must be listed systematically from head to toe.
c) Mentioning all major glands ensures maximum marks.
d) Diagrams can be used mentally to recall positions accurately.

 

84. Explain the Functions of all glands in our body [5 Marks]

Answer:
1. Hypothalamus regulates releasing hormones that control the pituitary gland.
2. Pituitary gland secretes growth hormone and tropic hormones controlling other glands.
3. Thyroid gland secretes thyroxin to regulate carbohydrate, fat, and protein metabolism.
4. Adrenal glands secrete adrenaline to prepare the body for emergency fight or flight situations.
5. Pancreas secretes insulin and glucagon to maintain blood glucose levels.
6. Gonads secrete testosterone or estrogen and progesterone to regulate secondary sexual characters and reproduction.

Teacher's Note:
a) Each gland has specific target organs and distinct hormonal secretions.
b) Balance of hormones is critical for healthy human metabolism.
c) Grouping related functions helps in concise memorization.
d) Mentioning master gland status for the pituitary adds extra value.

 

85. What are the two main centers for the coordination of two systems? [2 Marks]

Answer:
1. The nervous system and the endocrine system are the two main systems for body coordination.
2. The central nervous system (brain and spinal cord) and the hypothalamus act as the primary integration centers.

Teacher's Note:
a) Coordination requires both rapid electrical signals and slow chemical signals.
b) Hypothalamus links the nervous system directly to the endocrine system.

 

86. What all can happens if the pituitary glands do not function properly [3 Marks]

Answer:
1. Deficiency of growth hormone during childhood leads to dwarfism.
2. Excess secretion of growth hormone during childhood leads to gigantism.
3. Improper secretion affects the functioning of other dependent endocrine glands like thyroid, adrenals, and gonads.

Teacher's Note:
a) Pituitary is often called the master gland due to its control over others.
b) Hormonal imbalances produce distinct clinical conditions.
c) Both hypersecretion and hyposecretion cause major disorders.

 

87. How hormones help in coordinated growth? [2 Marks]

Answer:
1. Hormones like growth hormone regulate overall physical stature and bone elongation.
2. Thyroxin ensures balanced metabolic rate required for proper tissue growth and organ development.

Teacher's Note:
a) Growth requires precise chemical regulation over prolonged developmental periods.
b) Synergy between multiple hormones ensures proportional body growth.

 

88. Write the Sense organs of our body [1 Mark]

Answer:
1. The five sense organs of our body are eyes, ears, nose, tongue, and skin.

Teacher's Note:
a) Sense organs contain specific receptors for external environmental stimuli.

 

89. Is walking different from reflex action [3 Marks]

Answer:
1. Walking is a voluntary action controlled consciously by the cerebrum, whereas reflex action is an involuntary, automatic response.
2. Walking requires conscious thought, planning, and learning, while reflex actions are hardwired and bypassing conscious thought.
3. Walking involves complex skeletal muscle coordination through the brain, while reflexes are mediated primarily by the spinal cord via a reflex arc.

Teacher's Note:
a) Contrast voluntary versus involuntary pathways clearly.
b) Reflex actions are protective and extremely fast.
c) Walking can be initiated or stopped at will.

 

90. What do you understand by CNS? Explain [3 Marks]

Answer:
1. CNS stands for Central Nervous System.
2. It comprises the brain and the spinal cord.
3. It receives information from all parts of the body, integrates it, and coordinates responses.

Teacher's Note:
a) CNS acts as the main processing command center of the body.
b) Brain handles complex processing while spinal cord manages quick reflexes.
c) It connects with the peripheral nervous system for sensory-motor communication.

 

91. Draw Flow chart to show the classification of nervous system into various parts [3 Marks]

Answer:
1. Nervous System splits into Central Nervous System (CNS) and Peripheral Nervous System (PNS).
2. CNS comprises the Brain and the Spinal Cord.
3. PNS comprises the Cranial Nerves and Spinal Nerves, further branching into Somatic and Autonomic Nervous Systems.

Teacher's Note:
a) Hierarchical representation is essential for classification charts.
b) PNS connects the CNS to limbs and organs.
c) Autonomic system controls involuntary visceral functions.

 

92. What is synapse? What happens at the synapse between two neurons? How are the messages carried? [3 Marks]

Answer:
1. A synapse is the microscopic functional gap between the axon terminal of one neuron and the dendrite of the next neuron.
2. When an electrical impulse reaches the axonal end, it triggers the release of neurotransmitter chemicals into the synaptic cleft.
3. These chemicals cross the gap and start a similar electrical impulse in the dendrite of the next neuron.

Teacher's Note:
a) Synapses ensure one-way transmission of nerve impulses.
b) Neurotransmitters act as chemical bridges across the physical gap.
c) Electrical signals convert to chemical signals and back to electrical signals.

 

93. Who detects smell and taste in our body? [2 Marks]

Answer:
1. Olfactory receptors located in the nasal cavity detect smell.
2. Gustatory receptors located on the tongue detect taste.

Teacher's Note:
a) Olfactory receptors are chemo-receptors for airborne molecules.
b) Gustatory receptors respond to dissolved chemical substances in food.

 

94. Why does the food taste different when you nose is blocked? [3 Marks]

Answer:
1. Taste and smell work closely together in our brain to perceive complete flavor.
2. A blocked nose prevents volatile food odors from reaching the olfactory receptors.
3. Without olfactory input, the gustatory sense alone provides incomplete flavor perception.

Teacher's Note:
a) Flavor is a combined perception of taste and smell.
b) Nasal congestion blocks olfactory receptor stimulation.
c) This explains why food lacks appeal during a severe cold.

 

95. Explain Insulin and diabetes. [3 Marks]

Answer:
1. Insulin is a hormone secreted by the pancreas that regulates blood glucose levels by converting excess sugar into glycogen.
2. Diabetes mellitus occurs when the pancreas fails to produce sufficient insulin or body cells stop responding to it.
3. This leads to high blood sugar levels, causing frequent urination, fatigue, and excess glucose in urine.

Teacher's Note:
a) Insulin maintains sugar homeostasis in human blood.
b) Insufficient insulin leads to chronic hyperglycemia.
c) Regular medication or insulin injections are used to manage diabetes.

 

96. Draw and mark Location of all glands in the human body [5 Marks]

Answer:
1. Hypothalamus, pituitary, and pineal glands are marked in the head.
2. Thyroid and parathyroid glands are marked in the throat/neck region.
3. Thymus is marked in the chest, and pancreas in the upper abdomen.
4. Adrenal glands are marked as caps on both kidneys.
5. Testes (in males) or ovaries (in females) are marked in the lower abdomen.

Teacher's Note:
a) Diagram must clearly indicate relative positions from head to pelvis.
b) Labeling lines should point directly to the correct organ.
c) Both male and female specific gonad placements should be understood.
d) Neat sketching carries full marks in board examinations.

 

97. Write the Function of thyroxin hormone [2 Marks]

Answer:
1. Thyroxin regulates carbohydrate, protein, and fat metabolism in the body.
2. It promotes overall physical growth and balanced body development.

Teacher's Note:
a) Iodine is essential for the synthesis of thyroxin.
b) Iodine deficiency causes goiter.

 

98. Name one hormone found in male [1 Mark]

Answer:
1. Testosterone is the primary hormone found in males.

Teacher's Note:
a) It is secreted by the testes and controls male secondary sexual characteristics.

 

99. Write the Function of hypothalamus, pituitary gland and cerebrum [3 Marks]

Answer:
1. Hypothalamus regulates body temperature, hunger, thirst, and controls pituitary hormone secretion.
2. Pituitary gland secretes growth hormone and acts as the master gland controlling other endocrine glands.
3. Cerebrum controls voluntary actions, memory, reasoning, and processes sensory information.

Teacher's Note:
a) Hypothalamus links nervous and endocrine systems.
b) Pituitary coordinates secondary endocrine responses.
c) Cerebrum is the primary center for intelligence and thinking.

 

100. Explain the Main thinking part of brain [2 Marks]

Answer:
1. The forebrain is the main thinking part of the brain.
2. It contains regions that receive sensory impulses, process information, and control voluntary actions.

Teacher's Note:
a) Forebrain forms the largest and most complex part of the human brain.
b) It manages memory, learning, and reasoning.

 

101. Explain the Parts covered under hind brain [3 Marks]

Answer:
1. Cerebellum: Responsible for maintaining posture, balance, and precision of voluntary movements.
2. Medulla Oblongata: Controls involuntary actions like blood pressure, heartbeat, salivation, and vomiting.
3. Pons: Acts as a bridge relaying signals between the cerebrum and cerebellum.

Teacher's Note:
a) Hindbrain manages vital involuntary life functions.
b) Damage to medulla can result in fatal consequences.
c) Cerebellum coordinates muscle movement smoothness.

 

102. Name the part which control blood pressure, salivation and vomiting control [1 Mark]

Answer:
1. Medulla oblongata in the hindbrain controls blood pressure, salivation, and vomiting.

Teacher's Note:
a) These are involuntary reflex actions managed without conscious thought.

 

103. What do you understand by the term reflex arc [3 Marks]

Answer:
1. The pathway taken by nerve impulses in a reflex action is called a reflex arc.
2. It consists of a receptor, sensory neuron, integration center in the spinal cord, motor neuron, and an effector.
3. It provides a rapid, automatic response to harmful stimuli to prevent physical injury.

Teacher's Note:
a) Reflex arcs bypass the brain for faster response times.
b) The spinal cord processes the immediate signal.
c) Effector muscles or glands execute the protective reaction.

 

104. Write the Function of gustatory receptor [1 Mark]

Answer:
1. Gustatory receptors detect the sense of taste from food substances.

Teacher's Note:
a) These are chemical receptors located primarily on the tongue.

 

105. Write an assay on reflex action [5 Marks]

Answer:
1. Definition: A reflex action is a rapid, automatic, and involuntary response of the body to a specific stimulus.
2. Pathway: The nerve pathway involved in carrying electrical signals during a reflex action is known as a reflex arc.
3. Components: It starts at sensory receptors, passes through sensory neurons to the spinal cord, and travels via motor neurons to effectors.
4. Significance: It protects the body from sudden potential harms like burning or pricking by acting instantly.
5. Brain Involvement: While the spinal cord coordinates the quick response, information also reaches the brain so we become aware of the action afterwards.

Teacher's Note:
a) Essays should cover definition, pathway, components, and biological importance.
b) Emphasize the protective role of reflexes in daily life.
c) Mentioning the spinal cord as the processing center is vital.
d) Clear separation of points helps achieve full marks.