Case Based Questions : Tissues | Science Class 9 PDF Download

Q1: Read the following passage and answer the questions that follow:

Plants have two main types of tissues: meristematic tissue (which helps in growth) and permanent tissue (which performs specialized functions). Meristematic tissue is found at the tips of roots and shoots and allows the plant to grow in length. It also occurs at the base of leaves in some plants, allowing regrowth.Once meristematic cells divide, they differentiate and form permanent tissues that perform different functions. For example, parenchyma stores food, collenchyma provides flexibility, and sclerenchyma gives strength.

i. Where is apical meristem found in plants? (1 mark)
ii. How does meristematic tissue differ from permanent tissue? (2 mark)
iii. Why does cutting the tip of a plant shoot stop its growth? (1 mark)

Ans:
i. Apical meristem is found at the tips of roots and shoots, helping plants grow in length.
ii. Meristematic tissue is made of actively dividing cells, while permanent tissue consists of differentiated cells that perform specialized functions like support and storage.
iii. If the tip of a plant is cut, apical meristem is removed, stopping growth in that direction because no new cells are produced for elongation.

Q2: Read the following passage and answer the questions that follow:

Plants need a transport system to move water and food. Xylem transports water and minerals from roots to the entire plant, while phloem transports food from the leaves to other parts.Xylem consists of tracheids and vessels (which transport water), xylem fibers (which provide support), and xylem parenchyma (which stores food). Phloem consists of sieve tubes, companion cells, phloem fibers, and phloem parenchyma. Unlike xylem, phloem cells are living.

 i. Name any two components of xylem. (1 mark)
ii. How does xylem differ from phloem in structure and function? (2 mark)
iii. Why do plants need both xylem and phloem? (1 mark)

Ans:
i. Two components of xylem: Tracheids and vessels.
ii. Differences between xylem and phloem:
Xylem: Transports water; consists of dead cells like tracheids and vessels.
Phloem: Transports food; consists of living cells like sieve tubes.
iii. Plants need xylem for water transport and phloem for food transport to support growth and survival.

Q3: Read the following passage and answer the questions that follow:

Epithelial tissue forms the protective covering of the body and lines internal organs. There are different types:
Squamous epithelium (flat cells) helps in exchange of substances (e.g., lung alveoli).
Cuboidal epithelium (cube-shaped cells) is found in kidney tubules and glands.
Columnar epithelium (tall cells) lines the intestine and helps in absorption.
Ciliated epithelium has hair-like cilia that move mucus in the respiratory tract.

i. What is the function of squamous epithelium? (1 mark)
ii. How does ciliated epithelium help in the respiratory system? (2 mark)
iii. Why do epithelial cells have no intercellular spaces? (1 mark)

Ans:
i. Squamous epithelium allows exchange of gases in the lungs and diffusion of substances in blood vessels.
ii. Ciliated epithelium has hair-like cilia that move mucus and trapped dust particles out of the respiratory tract, keeping the airways clear.
iii. Epithelial cells form a protective barrier, so they are tightly packed with no spaces to prevent substances from passing through unwanted areas.

i. Which type of muscle is found in the heart? (1 mark)
ii. How do striated and smooth muscles differ in structure and function? (2 mark)
iii. Why does cardiac muscle never fatigue? (1 mark)

Ans:
i. Cardiac muscle is found in the heart.
ii. Striated muscles are voluntary, cylindrical, and multinucleate, helping in body movement.
Smooth muscles are involuntary, spindle-shaped, and uninucleate, helping in internal organ movement.
iii. Cardiac muscles never fatigue because they have a high number of mitochondria, ensuring a continuous supply of energy.

Q5: Read the following passage and answer the questions that follow:

Nervous tissue helps in transmitting signals in the body. It consists of neurons, which have:
Dendrites (receive signals)
Axons (transmit signals)
Synapses (pass signals to other neurons)
The brain, spinal cord, and nerves are made of nervous tissue, allowing quick responses to stimuli.

i. Name any two parts of a neuron. (1 mark)
ii. How does a neuron transmit signals in the body? (2 mark)
iii. Why do nerve cells have long axons? (1 mark)

Ans:
i. Two parts of a neuron: Dendrites and axon.
ii. Neurons receive signals through dendrites, transmit them via the axon, and pass them to another neuron or muscle at the synapse.
iii. Axons are long to allow faster transmission of signals over long distances in the body.

Q6: Read the following passage and answer the questions that follow:

Plants need protective tissues to prevent water loss and protect against mechanical injury and infections. The epidermis is a single layer of cells covering the plant body. It secretes a waxy cuticle in some plants to prevent water loss.
In older plants, the outer layer of the stem changes into cork (bark), made of dead cells. Cork cells contain suberin, a waterproof substance that prevents the entry of water and gases.

i. What is the function of the waxy cuticle on the epidermis? (1 mark)
ii. How does cork protect a plant? (2 mark)
iii. Why do desert plants have a thicker epidermis? (1 mark)

Ans:
i. The waxy cuticle on the epidermis reduces water loss by preventing excessive evaporation.
ii. Cork protects a plant by forming a thick, waterproof barrier that prevents water loss, microbial infections, and mechanical damage.
iii. Desert plants have a thicker epidermis to reduce water loss, helping them survive in dry conditions.

Q7: Read the following passage and answer the questions that follow:

Connective tissues provide support and connection in the body.

i. Which connective tissue joins muscles to bones? (1 mark)
ii. How do ligaments differ from tendons? (2 marks)
iii. Why can we bend our ear but not our bones? (1 mark)

Ans:
i. Tendons join muscles to bones.
ii. Ligaments are elastic and join bones to bones, allowing some movement. Tendons are stronger but less elastic, helping muscles move bones.
iii. The ear has cartilage, which is flexible, while bones are hard and rigid.

Q8: Read the following passage and answer the questions that follow:

Blood is a fluid connective tissue that transports oxygen, nutrients, and waste throughout the body. It contains:
Red Blood Cells (RBCs), which carry oxygen.
White Blood Cells (WBCs), which fight infections.
Platelets, which help in blood clotting.
Plasma, the liquid part that carries hormones, nutrients, and waste.

i. What is the function of RBCs? (1 mark)
ii. How do WBCs and platelets help the body? (2 marks)
iii. Why does blood clot when we get a cut? (1 mark)

Ans:
i. RBCs transport oxygen using hemoglobin.
ii. WBCs fight infections by attacking germs, while platelets help in blood clotting, preventing excessive blood loss.
iii. Blood clots due to platelets, which form a plug at the injury site and release clotting factors to stop bleeding.

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Q9: Read the following passage and answer the questions that follow:

i. Which type of muscle is found in the intestine? (1 mark)
ii. How do skeletal muscles differ from smooth muscles?  (1 mark)
iii. Why are skeletal muscles called voluntary muscles? (1 mark)

Ans:
i. Smooth muscle is found in the intestine.
ii. Skeletal muscles are voluntary, cylindrical, and multinucleate, helping in movement. Smooth muscles are involuntary, spindle-shaped, and uninucleate, controlling automatic functions.
iii. Skeletal muscles are called voluntary because we can control them consciously, like moving arms or legs.

Q10: Read the following passage and answer the questions that follow:

i. What is the function of dendrites in a neuron? (1 mark)
i. How does a neuron transmit signals? (2 mark)
ii. Why do reflex actions occur faster than normal responses? (1 mark)

Ans:
i. Dendrites receive signals from other neurons or the environment.
ii. Neurons transmit signals by carrying electrical impulses from dendrites to axons, then passing them to another neuron or muscle.
iii. Reflex actions occur faster because they bypass the brain and are controlled by the spinal cord, reducing reaction time.