Class 9 Science Exploration Chapter 3 Tissues in Action Excercise

1. Meristematic tissues divide repeatedly. What property of their cells allows them to do this?

(i) They have thick walls for protection.

(ii) They contain large vacuoles that store nutrients.

(iii) They have thin walls, dense cytoplasm and large prominent nucleus.

(iv) They are functionally differentiated cells.

2. If a plant is unable to transport food from leaves to roots which tissue is malfunctioning?

(i) Xylem

(ii) Phloem

(iii) Epidermis

(iv) Sclerenchyma

3. Why are the epithelial tissues that line an animal's internal organs usually only one or a few cells thick?

(i) To store food efficiently.

(ii) To provide maximum strength.

(iii) To allow quick exchange of materials across them.

(iv) To reduce friction.

4. You can perform these two jumps (Fig. 3.21):

Straight-leg jump-keep knees and ankles stiff.

Normal jump-bend knees and ankles naturally.

How did your ankle, knee and hip positions differ between the two jumps?

5. Which type of joint is involved when you bend your knees and ankles?

(i) Ball and socket

(ii) Hinge

(iii) Pivot

6. In each of the following cases (A, B, C and D), choose the correct option

as given below:

(i) Both (A) and (R) are true, and (R) is the correct explanation of (A).

(ii) Both (A) and (R) are true, but (R) is not the correct explanation of (A).

(iii) (A) is true, but (R) is false.

(iv) (A) is false, but (R) is true.

A. Assertion: Epithelium is well-suited for gas exchange in the lungs.

Reason: It consists of multiple layers of tall cells that slow down

diffusion.

B. Assertion: Cardiac muscle can contract continuously without fatigue.

Reason: Cardiac muscle cells have a high number of mitochondria

Exploratio

and an abundant blood supply.

Tissues in Action

C. Assertion: Tendons connect bone to bone and allow joint movement.

Reason: Tendons are made of tough connective tissue that transmits force from muscle to bone.

D. Assertion: In a hinge joint, movement occurs primarily in one

plane.

Reason: The bone ends are shaped to allow sliding in all directions.

7. Plot a graph between the age of a tree (in years) on the x-axis and the

diameter of the tree (in cm) along with the number of annual rings formed over time on the y-axis, using the data given in the Table 3.7.

Table 3.7: Data related to the age of a teak tree, and corresponding increase in the diameter of stem and number of annual rings

S. No.

Age of the teak tree (Years)

DBH (Diameter at Breast Height) of tree (cm)

Number of annual rings for

(i) Analyse the graph in terms of the diameter of the stem over time and share the interpretation.

(ii) What is the relation between the diameter of the teak tree to the annual rings formed?

(iii) Which specialised tissue is responsible for the girth of the stem and where is it located?

8. A researcher carried out an experiment in which she took two carrots of similar size. She placed one carrot in plain water and the other carrot in concentrated salt solution (l'ig. 2.21). After 24 hours she recorded her observations.

Fig. 2.21: Experimental

set-up having carrol (a) in plain water, and (b) in salt solution

(i) What hypothesis does she want to test through this experiment?

(ii) What would you suggest for the improvement of this experiment?

(iii) Why does the carrot in plain water stay stiff and crunchy, but the carrot in concentrated salt solution become rubbery and limp?

9. Indicate the presence or absence of following structures in bacterial and animal cells:

Structures in a cell

Bacterial cell

Animal cell

Chromosome

Nucleus

Mitochondria

Golgi complex

Chromoplasts

10. Carry out the following experiment:

Take four peeled potato halves and scoop each one out to make potato cups. One of these potato cups should be made from a boiled potato. Place each of the potato cups in a beaker containing water (lig. 2.22). Now, set up the experiment as follows:

(a) Keep Cup A empty.

(b) Add one teaspoon sugar in Cup B.

(c) Add one teaspoon salt in Cup C.

(d) Add one teaspoon sugar in the boiled potato in Cup D.

Observe the four potato cups at least two hours and answer the following questions:

(1) Explain why water gathers in the hollowed portion of Cup B and Cup C.

(ii) Why is Cup A necessary for this experiment?

(iii) Explain why water does not gather in the hollowed portions of Cups A and D.

Fig. 2.72: Experimental set-up

11. Identify the pair that incorrectly matches the cell organelle with its function.

(i) Ribosome-Protein synthesis

(ii) SER Lipid and cellulose synthesis

(iii) Lysosome Digestion of foreign agents

12. What outcome do you expect, if all the mitochondria are removed from a eukaryotic cell?

13. Which phenomenon inhibits the formation of tumors in the human body? Can plants also develop tumors? Explain.

26 Exploration | Grade 9

Cell: The Building Block of Life

14. The cell membrane of a cell is made up of proteins and lipids. Which cell organelles help in the synthesis of cell membrane? Write the path of these compounds from their site of synthesis to the cell membrane and show this through a labelled diagram.

15. What would happen if gametes are formed by mitotic divisions?

16. A farmer, Deepa, was very happy with the harvest of amla (Indian Gooseberry) and lemons on her farm. However, she could sell only one-fourth of the produce in the local market. Recognising that a significant amount of produce may be lost post-harvest, she employed a traditional yet scientifically sound method to extend the shelf life of amla and lemons. She turned perishable produce into profitable products, such as pickles and sharbat. She used the excess produce to prepare pickles, murabbas, and sharbat by adding appropriate amounts of salt, sugar, or jaggery to small pieces of fruit and their juices. These were then stored in small glass bottles for sale, helping her prevent the wastage of post-harvest produce. This shift from farming to agro-processing would strengthen food security and boost the local economy, creating a sustainable model that cuts waste while increasing her income. Based on the above passage answer the following questions: Med

Answers

Here are the answers:

1. Meristematic tissues divide repeatedly. What property of their cells allows them to do this?

Answer: (iii) They have thin walls, dense cytoplasm and a large prominent nucleus.

2. If a plant is unable to transport food from leaves to roots, which tissue is malfunctioning?

Answer: (ii) Phloem

3. Why are the epithelial tissues that line an animal's internal organs usually only one or a few cells thick?

Answer: (iii) To allow quick exchange of materials across them.

4. How did your ankle, knee and hip positions differ between the two jumps?

Answer:

Straight-leg jump: Knees and ankles remain straight and stiff; hips bend very little.

Normal jump: Knees and ankles bend naturally, and the hips also bend, making the jump easier and more powerful.

5. Which type of joint is involved when you bend your knees and ankles?

Answer: (ii) Hinge joint

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6. Assertion and Reason

A.

Assertion: True

Reason: False (Gas exchange occurs through a single layer of thin cells, not multiple layers.) Answer: (iii)

B.

Assertion: True

Reason: True, and it correctly explains the assertion. Answer: (i)

C.

Assertion: False (Tendons connect muscle to bone.)

Reason: True Answer: (iv)

D.

Assertion: True

Reason: False (Sliding in all directions occurs in gliding joints, not hinge joints.) Answer: (iii)

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7. Graph-based Questions

(i) Interpretation of the graph

As the age of the teak tree increases, the diameter of the stem also increases.

The increase is gradual, showing continuous secondary growth.

(ii) Relation between diameter and annual rings

The number of annual rings is equal to the age of the tree (one ring forms each year).

As the number of annual rings increases, the diameter of the tree also increases.

(iii) Which specialised tissue is responsible for the girth of the stem and where is it located?

Answer:

Tissue: Cambium (Lateral Meristem)

Location: Between the xylem and phloem in the stem. It produces new xylem and phloem cells, increasing the stem's girth.

Answer Key:

1. (i

ii)

2. (ii)

3. (iii)

4. Descriptive

5. (ii)

6. A–(iii), B–(i), C–(iv), D–(iii)