Grade 9: Body structure and life Process

Cell Tissue and organs

Very short answer type questions.

1.     Where is apical meristem present?

Apical meristem is found at the tip of root and stem.

2.     Name the tissue which transport food from leaves to other parts of the plant.

Phloem is the name of tissue which transport food from leaves to other parts of plant.

3.     What happens to a plant if its all apical meristematic tissues stop functioning?

If all the apical meristematic tissue stops functioning then the plant will not grow taller in heigh.

4.     Name the tissue present at the growing tip of stem and roots.

Apical meristematic tissue is present at the growing tip of stem and roots.

5.     Name the tissue at the base of the leaves or internodes on twigs.

Intercalary meristem is present at the base of the leaves or internodes on twigs.

6.     Which type of muscle is found in intestine?

Smooth (involuntary) muscle is found in the intestine.

7.     Define voluntary muscles.

Muscles that can be moved under the control of our will are called voluntary muscles.

8.     Define involuntary muscles.

Muscles that are not under the control of our conscious mind are called voluntary muscles.

9.     Name the hardest and softest tissue of animals.

The hardest tissue is tooth enamel and the softest tissue of animal is brain tissue.

10.                        Define adipose tissue.

A connective tissue that stores fat, provides insulation, and cushions body organs is defined as adipose tissue.

Short answer type questions.

11.                        Xylem and phloem are also called Vascular tissues or conducting tissues. Why?

Xylem and phloem are also called vascular tissues or conducting tissues because they transport water and minerals to the leaves for photosynthesis and prepared food for production of energy and storge to different parts of plant.

12.                        Write two differences between axon and dendron.

Axon	Dendron
1. A single, long, thin extension of a neuron.	1. Short, branched extensions of a neuron.
2. Carries nerve impulses away from the cell body.	2. Carries nerve impulses towards the cell body.

13.                        If an apex of a plant is cut down, it does not grow long. why?

Cutting off a plant's apex, prevents it from growing long because the apical meristem at tip is what causes the plant to grow lengthwise ; cutting the apex removes this meristematic tissue, which prevents the plant from elongating Rather than growing tall, the plant begins to grow sideways by generating more branches from the lateral buds.

14.                        Write any two differences between xylem and phloem.

Any two differences between Xylem and Phloem

Xylem	Phloem
1. Transports water and minerals from roots to other parts.	1. Transports food (prepared in leaves) to other parts.
2. Consists mainly of dead cells (except xylem parenchyma).	2. Consists mainly of living cells (except phloem fibers).

 

15.                        Intercellular species are absent in cell of Sclerenchyma Give a reason.

16.                        Intercellular spaces are absent in sclerenchyma cells because the cells of sclerenchyma are thick-walled and tightly packed with lignin deposition, leaving no intercellular space.

17.                        Write two differences between sclerenchyma and parenchyma tissue.Two differences between Sclerenchyma and Parenchyma tissue

Sclerenchyma	Parenchyma
1. Cells are thick-walled and lignified.	1. Cells are thin-walled.
2. Provides mechanical support.	2. Stores food and performs photosynthesis.

 

18.                        Write to similarities between straited and cardiac muscles.

Two similarities between Striated and Cardiac muscles

1.     Both are striated (striped) in appearance under a microscope.

2.     Both help in movement by contraction and relaxation.

19.                        Blood is considered as a fluid connective tissue. Give a reason.

blood considered a fluid connective tissue because blood connects different organs of the body by transporting oxygen, food, hormones, and wastes. It also has a liquid matrix (plasma) in which cells are suspended.

20.                        Why is connected tissue called so?

21.                        connective tissue called so because it connects, supports, and binds different organs and tissues of the body together.

22.                        Write to differences between cartilage and bone.

·       Two differences between Cartilage and Bone

Cartilage	Bone
1. Soft, flexible, and elastic connective tissue.	1. Hard, rigid, and strong connective tissue.
2. Cells are embedded in a flexible matrix of chondrin.	2. Cells are embedded in a hard matrix of calcium salts.

 

Long Answer type questions:

1. Draw the structure of meristematic tissue and label its any two parts.

2. Draw a neat diagram of transverse section of collenchyma tissue and label its any four parts.

3. Draw a well labelled diagram of nerve cell.

5. Draw unstraited muscle tissue and mention its occurrence, characteristics and function.

Occurrence of Unstriated Muscles

Unstriated muscle tissue, also known as smooth muscle, is found mainly in the walls of internal organs such as the stomach, intestines, urinary bladder, uterus, blood vessels, and respiratory tract.

Characteristics of Unstriated Muscles

 

• Composed of elongated, spindle-shaped cells with a single, centrally located nucleus.
• Lacks striations, appearing smooth under a microscope.
• Cells are arranged in sheets or layers within the organ walls.

Functions of Unstriated Muscles

• Movement of internal organs: Propel food and fluids through digestive tract, regulate diameter of blood vessels, and control airflow in the respiratory tract.
• Involuntary actions: Responsible for involuntary motions such as peristalsis, vasodilation/constriction, and moving urine through the urinary system.

5. Xylem and phloem tissues are very important for plants. Explain.

Xylem and phloem tissues are very important for plants because of the following reasons.

Xylem

• It transports water and dissolved minerals absorbed from the soil through roots to all parts of the plant, primarily upwards.
• It provides mechanical support to the plant due to lignified, thick walls of xylem cells, helping plants stand upright.

It ensures hydration and nutrient supply essential for plant growth, photosynthesis, and metabolic activities.

Phloem

• It transports organic nutrients, mainly sugars (products of photosynthesis), from the leaves where they are synthesized to other parts like stems, roots, and storage organs.
• It acts as a distribution system delivering nutrients both upward and downward as per the plant’s needs.

It supplies energy materials for growth, development, and storage in non-photosynthetic parts.

6. Xylem is complex permanent tissue. Justify.

7. Explain the utility of tissue in multicellular organisms.

8. Given alongside is a structure of a tissue. Study the diagram and answer the following question.

a) Name the structure shown in diagram.

The structure shown in the diagram is cubical epithelium.

b) Name the parts labelled as A, B and C.

A is Cuboidal cell, B is nucleus and C is basement membrane.

c) Where is this structure located in our body?

It is located in the uriniferous tubules of kidneys, gonads, sweat glands, germinal layer of testis and ovary.

d) Write its importance for animal body.

 It is important for animal body as it give protection to the internal organ, it secretes various kinds of juices, enzymes and hormones, sex cells, filters blood and excrete urine, sweat and unwanted waste products.

9. Observe the figure and answer the following question:

a) What does the figure show?

The figure shows the meristematic tissue.

b) Label the parts A, B and C.

Part A is apical meristem, Part B is intercalary meristem and part C is lateral meristem.

c) Write the function of A and C.

A increases the length of the stem and twigs and C increases the girth.

d) Which part is responsible for increasing the growth of internode?

Part B (intercalary meristem) is responsible for increasing the growth of internode.

10. Study the given diagram and answer the following questions.

a) Identify figure: A, B and C.

Figure A is sclerenchyma, B is parenchyma and C is collenchyma?

b) Which one of them provides both mechanical strength as well as flexible?

Figure A (Sclerenchyma) provides both mechanical strength as well as flexibility.

c) Which one of them is commercially exploited to obtained Hemp and jute?

Figure A (Sclerenchyma) is commercially exploited to obtained Hemp and jute.

d) Which one of them can be modified to form air cavities in aquatic plants?

Figure B  (Parenchyma) can be modified to form air cavities in aquatic plants.

e) Which one of them has heavy deposition of lignin?

Figure A (Sclerenchyma) has heavy deposition of lignin.

11. The diagram given alongside are types of animals tissues. Study the diagram and answer the following questions.

a) Identify the diagram A and B.

The diagram A is cardiac muscles and B is skeletal muscle.

b) Label the parts X and Y.

The part x is nucleus and Y is straitation.

c) Write the special nature of A.

The special nature of A is that it keeps on contracting and relaxing without being fatigue throughout the life.

d) Which one is under the control of our will?

Figure B (Skeletal muscle) is under the control of our will.

HUMAN NERVOUS SYSTEM

Very short answer type questions:

1. What is the structural and functional unit of nervous system?

 The neuron is the structural and functional unit of the nervous system.

2. What are the three major parts of human brain?

The three major parts are:

• Cerebrum
• Cerebellum
• Medulla oblongata (part of brain stem)

3. Which part of brain controls heart beat?

 The medulla oblongata controls heartbeat (as well as breathing and blood pressure).

4. What do we call the state in a human body if cerebrum is not functioning well?

 If the cerebrum does not function well, the state is called coma.

5. Define sensory nerve (afferent) and motor nerve (efferent).

• Sensory nerve (afferent): A nerve that carries impulses from sense organs to the brain or spinal cord.
• Motor nerve (efferent): A nerve that carries impulses from the brain or spinal cord to muscles or glands.

6. What is reflex arc?

 A reflex arc is the shortest pathway of nerve impulse involved in a reflex action.

7. Define neuron, axon and dendrite.

• Neuron: The basic structural and functional unit of the nervous system specialized to transmit nerve impulses.
• Axon: The long fiber of a neuron that carries impulses away from the cell body to other neurons, muscles, or glands.
• Dendrite: The short, branched projections of a neuron that receive impulses from other neurons and carry them toward the cell body.

8. What is synapse?

A synapse is the junction between two neurons, where the transmission of nerve impulses takes place, usually through chemical neurotransmitters.

Short answer type question.

1. What will happen if spinal cord is injured at any point due to disease or accident? Write any two effects of it.

If spinal cord is injured at any point due to disease or accident, the following are the effects of it are:

• Loss of sensation in body parts below the injury.
• Loss of movement (paralysis) in body parts below the injury.

2. Write two functions that will be affected if cerebellum gets damaged.

• Body balance and posture will be affected.
• Coordination of voluntary movements will be disturbed.

3. Draw a neat and labelled diagram of nerve cell (neuron).

4. Why does reflex arc evolve in animals?

Reflex arc evolved to provide quick and automatic responses to harmful stimuli, protecting animals from injury and ensuring survival.

5. Write any two differences between axon and dendrites.

Axon Dendrites Long fiber carrying impulses away from cell body. Short, branched fibers carrying impulses to cell body. Usually one per neuron. Many per neuron.

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6. Write any two functions of cerebrospinal fluid.

Two functions of cerebrospinal fluid are:

• Protects brain and spinal cord by cushioning against shocks.
• Provides nutrients and removes waste from brain tissues.

7. Write two differences between sensory nerve and motor nerve.

Sensory Nerve Motor Nerve Carries impulses from sense organs to brain/spinal cord. Carries impulses from brain/spinal cord to muscles or glands. Helps in sensation (touch, pain, etc.). Helps in action (movement, secretion).

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8. Write two differences between cerebrum and cerebellum.

Cerebrum	Cerebellum
Largest part of brain, controls thinking, memory, emotions, voluntary actions.	Smaller part, controls balance, posture, coordination of movement.
Responsible for intelligence and consciousness.	Responsible for smooth body movement.

9. Write any two differences between spinal nerve and cranial nerve.

Spinal Nerve Cranial Nerve Arises from spinal cord. Arises from brain. 31 pairs in humans. 12 pairs in humans.

10. Hand is pulled quickly when a hot object is touched suddenly. Give a reason.

Hand is pulled quickly when a hot object is touched suddenly because of a reflex action. The sensory nerves send impulses to the spinal cord, which immediately sends a signal back through motor nerves to withdraw the hand, without waiting for the brain.

Long answer type questions.

1.     How does neuron work? Explain.

A neuron is the basic structural and functional unit of the nervous system. Its work is to receive, process, and transmit information in the form of nerve impulses (electrical signals).

The followings are the steps of how a neuron works:

The dendrites of a neuron receive signals from sense organs (like skin, eyes, ears) or from another neuron. These signals are in the form of tiny electrical changes.

The stimulus travels to the cell body  where the nucleus helps process the signal and maintain the cell’s functions. The message travels quickly along the axon.

At the end of the axon are axon terminals, which connect to another neuron by a gap called synapse. At synapse neuron release chemicals called neurotransmitters. These chemicals carry the message across to the next neuron or to an effector (muscle/gland).

If the message goes to a muscle, the muscle contracts, If it goes to a gland, the gland secretes something and if If it goes to another neuron, the process continues until the brain/spinal cord receives it.

 

 

 

 

 

 

 

 

 

2.      Explain the role of brain in reflex action.

In most reflexes, the spinal cord controls the action immediately, without waiting for the brain. This saves time and protects the body from harm.

After the reflex action happens, the spinal cord also sends information to the brain. This allows the brain to understand what happened (for example, that you touched something hot). The brain does not start the reflex, but it helps in recording, analyzing, and learning from the experience.

3.      What happens at the synapse between two neurons?

A synapse is the tiny gap between the axon terminal of one neuron and the dendrite of the next neuron. Nerve impulses cannot jump directly across this gap. Instead, a special process occurs:

o   An electrical nerve impulse travels down the axon of the first neuron to its axon terminal.

o   The axon terminal releases chemical messengers called neurotransmitters into the synaptic gap.

o   These neurotransmitters diffuse across the synapse and bind to receptors on the membrane of the next neuron’s dendrite.

o   This binding creates a new electrical impulse in the second neuron.

o   The impulse keeps traveling along the new neuron’s axon, carrying the message forward.

 

4.      On touching a hot plate, you suddenly withdraw your hands. Which category of neurons become active first and which one next?

On touching a hot plate, Sensory neurons (afferent neurons) activated first. In this case,

o   The heat is detected by receptors in the skin. Sensory neurons immediately carry this message (nerve impulse) from the skin to the spinal cord.

Next Motor neurons (efferent neurons) activated. Here, the spinal cord quickly processes the impulse through a reflex arc. Then motor neurons carry the command from the spinal cord to the muscles of the hand. The muscles contract, and we withdraw your hand quickly.

 

5.      Draw a schematic diagram to show reflects arc. Label the components of pathway.

6.      Draw a level diagram of human brain.

7.      Damage to medulla oblongata causes death of a human. Justify with a reason.

Damage to medulla oblongata causes death. The reason behind it is,

·       The medulla oblongata is the lowest part of the brain stem.

·       It controls the most vital involuntary activities of the body, such as:

o   Heartbeat regulation

o   Breathing (respiration)

o   Blood pressure

o   Swallowing and digestion reflexes

If the medulla oblongata is damaged, these life-sustaining functions stop immediately.

Without heartbeat and breathing, a person cannot survive.

8.      Suppose a motorcycle rider without helmet has just an accident and has suffered a spinal cord injury in this case which signal will get disrupted? And why?

Both sensory and motor signals will be disrupted, because the spinal cord is the main pathway for communication between brain and body.

As a result, the rider may suffer from loss of sensation and paralysis in body parts below the injured area.

9.      Give a schematic representation of the sequence of events which occur when bright light is focused on your eyes.

Sequence of Events (Pupil Reflex in Bright Light):

Bright light enters the eye → detected by receptors in the retina.

Sensory neurons carry the impulse to the brain (specifically, midbrain).

Brain (reflex center) processes the signal.

Motor neurons carry instructions to the muscles of the iris.

Circular muscles of the iris contract.

1.      Pupil becomes smaller (constricts) → less light enters the eye to protect the retina.

Schematic Representation (Flowchart Style):

Bright light

⬇️

Retina (receptor)

⬇️ (via sensory neuron)

Brain (reflex center)

⬇️ (via motor neuron)

Iris muscles (effector)

⬇️

Pupil constricts

10. How does impulse transmit in the reflex action when a hot body is touched?

11. Given alongside is a figure of a human brain in a vertical section.

a) Label the parts A, B, C and D.

b) What is the function of parts A B and C?

c) The path a has many folds. Write its advantage.

12. The diagram given below is a typical reflex arc.

a)      Name the parts labelled A, B, C and D.

b)     Why is it called a reflex arc?

c)      Name on simple reflex action which occurs along the path of a reflex arc.

 

 GLANDULAR SYSTEM

1. How does chemical coordination take place in animals?

Chemical coordination in animals takes place through hormones, wh ich are chemical messengers secreted by endocrine glands. Hormones travel via blood to target organs and regulate growth, metabolism, reproduction, and other body functions.

2. What will happen if a person does not consume iodine in his diet? Explain.

If iodine is not consumed, the thyroid gland cannot produce thyroxine hormone. This causes goitre, a disease in which the neck swells due to enlargement of the thyroid gland.

The adrenal gland secretes hormones like adrenaline (for stress response) and cortisol, aldosterone (for metabolism and salt balance). If it is removed:

• The body cannot respond properly to stress.
• Blood pressure, water–salt balance, and sugar metabolism are disturbed.
• The person cannot survive without adrenal gland.

3. What will happen if adrenal gland is removed? Explain.

The adrenal gland secretes hormones like adrenaline (for stress response) and cortisol, aldosterone (for metabolism and salt balance). If it is removed:

• The body cannot respond properly to stress.
• Blood pressure, water–salt balance, and sugar metabolism are disturbed.
• The person cannot survive without adrenal gland.

4. What will happen if thyroid does not function properly? Explain.

• If thyroid secretes less thyroxine → stunted growth, goitre, obesity, tiredness.
• If thyroid secretes too much thyroxine → weight loss, restlessness, anxiety.
• Thus, thyroid malfunction disturbs metabolism and body growth.

5. How does chemical coordination occur in plants?

In plants, chemical coordination is controlled by plant hormones (phytohormones) like:

• Auxins → cell elongation, phototropism.
• Gibberellins → stem elongation, seed germination.
• Cytokinins → cell division, delay ageing.
• Abscisic acid (ABA) → inhibits growth, causes wilting.
• Ethylene → fruit ripening.

6. Nervous and hormonal system together perform the function of coordination in human being. Justify the statement.

The nervous system coordinates quick responses through electrical impulses (e.g., reflex action).

The hormonal system controls slower but long-lasting processes (e.g., growth, puberty, metabolism).

Together, they maintain balance and coordination in the body. Example: in stress, brain signals adrenal glands to release adrenaline.

7. What is the need for a system of control and coordination in an organism?

Organisms need control and coordination to:

• Respond to internal and external stimuli.
• Regulate body functions like growth, respiration, digestion, reproduction.
• Maintain balance (homeostasis).
• Ensure survival in changing environments.

Without coordination, body parts cannot work harmoniously.

 

8. Given alongside is a diagram of male glandular system, study it and answer the following questions.

a) Write the name of parts A and D in the given diagram.

A is pituitary gland and D is Adrenal gland.

b) Write a similarity between thyroid gland and parathyroid gland.

Both thyroid and parathyroid glands are located in neck region and they are endocrine glands.

c) Write an effect for each due to over and under secretion of hormone secreted by master gland.

Due to the over secretion of hormone by master gland, gigantism occur in which height of a person dramatically increases and under secretion of it causes dwarfism.

d) In what respect is male human glandular system different from female human glandular system?

The male and female glandular systems mainly differ in the type of sex glands and the hormones they secrete: males have testes (testosterone), while females have ovaries (estrogen and progesterone).

Male	Female
Testes are the male sex glands.	Ovaries are the female sex glands.
Testes secrete testosterone, which controls male secondary sexual characters (beard, deep voice, muscle growth).	Ovaries secrete estrogen and progesterone, which control female secondary sexual characters (breast development, menstrual cycle, pregnancy).

9. A boy was not able to gain height. The doctor diagnosed that it is due to the deficiency of hormone. Study the above statement and answer the following questions.

a) Name the hormone and the gland which secretes this hormone.

Hormone: Growth hormone (Somatotropin)

Gland: Pituitary gland (Anterior lobe)

b) Which disease is he suffering from?

Dwarfism (due to deficiency of growth hormone in childhood).

c) Write the nature of this type of gland.

The pituitary gland is an endocrine gland. It secretes hormones directly into the bloodstream.

d) Explain the importance of this type of hormone for human being.

• Growth hormone is essential for the normal growth of bones and muscles.
• It regulates height, body structure, and physical development.
• It helps in protein synthesis and cell division.
• Proper secretion ensures healthy development during childhood and adolescence.

10. Given along side is a portion of the human body showing some important structure in ventral view. Study the diagram and answer the following question.

a) Identify the diagram as a gland. The gland is thyroid gland.

b) Label the parts A, B and C.

The part A is thyroid gland, B is Isthmus and C is trachea.

c) What will happen if this gland does not work properly.

If this gland does not work properly, then cretinism, myxoedema, goitre and hyperthyroidism may occur.

d) Is there any duct to carry the secretion of part A? If so, give its name.

No, there is not any duct to carry secretion of part A since it is an endocrine gland.