NCERT Solutions Class 9 Science Chapter 6 Tissues

Class 9 Science
NCERT Solutions
Tissues

1. What is a tissue?
Answer : Tissue is a group of cells that are similar in structure and are organised together to perform a specific task.

2. What is the utility of tissues in multi-cellular organisms?
Answer : In multicellular organisms, the different types of tissues perform different functions. Since a particular group of cells carry out only a particular function, they do it very efficiently.
So, multicellular organisms possess a definite division of labour.

Tissues

1. Name types of simple tissues.
Answer : Simple permanent tissues are of three types:→ Parenchyma
→ Collenchyma
→ Sclerenchyma
Parenchyma tissue is of further two types:
• Aerenchyma
• Chlorenchyma

2. Where is apical meristem found?
Answer : Apical meristem is present at the growing tips of stems and roots.

3. Which tissue makes up the husk of coconut?
Answer : Sclerenchyma tissue makes up the husk of coconut.

4. What are the constituents of phloem?
Answer : The constituents of phloem are:
→ Sieve tubes
→ Companion cells
→ Phloem parenchyma
→ Phloem fibres

Tissues

1. Name the tissue responsible for movement in our body.
Answer : Muscular tissue

2. What does a neuron look like?
Answer : Neuron look like a star shaped cell with a tail.

3. Give three features of cardiac muscles.
Answer : Three features of cardiac muscles are:
→ Cardiac muscles are involuntary muscles that contract rapidly, but do not get fatigued.
→ The cells of cardiac muscles are cylindrical, branched, and uninucleate.
→ They control the contraction and relaxation of the heart.

4. What are the functions of areolar tissue?
Answer : Functions of areolar tissue:
→ It helps in supporting internal organs.
→ It helps in repairing the tissues of the skin and muscles.

Excercise

1. Define the term "tissue".
Answer : Tissue is a group of cells that are similar in structure and are organized together to perform a specific task.

2. How many types of elements together make up the xylem tissue? Name them.
Answer : Xylem is composed of following elements:
→ Tracheids
→ Vessels
→ Xylem parenchyma
→ Xylem fibres

3. How are simple tissues different from complex tissues in plants?
Answer :

4. Differentiate between parenchyma, collenchyma and sclerenchyma, on the basis of their cell wall.
Answer :

5. What are the functions of the stomata?
Answer : The functions of stomata are:
→ The exchange of gases (CO2 and O2) with the atmosphere.
→ The loss of excess water in the form of water vapour which is known as transpiration.

6. Diagrammatically show the difference between the three types of muscle fibres.
Answer : The three types of muscle fibres are: Striated muscles, smooth muscles (unstriated muscle fibre), and cardiac muscles.

7. What is the specific function of the cardiac muscle?
Answer : The specific function of the cardiac muscle is to control the contraction and relaxation of the heart.

8. Differentiate between striated, unstriated and cardiac muscles on the basis of their structure and site/location in the body.
Answer :

9. Draw a labelled diagram of a neuron.
Answer :

10. Name the following:

(a) Tissue that forms the inner lining of our mouth.
Answer : Epithelial tissue

(b) Tissue that connects muscle to bone in humans.
Answer : Tendon

(c) Tissue that transports food in plants.
Answer : Phloem

(d) Tissue that stores fat in our body.
Answer : Adipose tissue

(e) Connective tissue with a fluid matrix.
Answer : Blood

(f) Tissue present in the brain.
Answer : Nervous tissue

11. Identify the type of tissue in the following: skin, bark of tree, bone, lining of kidney tubule, vascular bundle.
Answer : → Skin: Stratified squamous epithelial tissue
→ Bark of tree: Simple permanent tissue
→ Bone: Connective tissue
→ Lining of kidney tubule: Cuboidal epithelial tissue
→ Vascular bundle: Complex permanent tissue

12. Name the regions in which parenchyma tissue is present.
Answer : Leaves, fruits, and flowers are the regions where the parenchyma tissue is present.

13. What is the role of epidermis in plants?
Answer : Epidermisis present on the outer surface of the entire plant body which perform following role:
→ It is a protective tissue of the plant body.
→ It protects the plant against mechanical injury.
→ It allows exchange of gases through the stomata.

14. How does the cork act as a protective tissue?
Answer : The outer protective layer or bark of a tree is known as the cork. It is made up of dead cells. Therefore, it protects the plant against mechanical injury, temperature extremes, etc. It also prevents the loss of water by evaporation.

15. Complete the table:

Answer :

Question. Among the following, which has the highest BRAIN TO BODY LENGTH ratio?
(a) Human
(b) Monkey
(c) Cat
(d) Squirrel

Answer : B

Question. The figure below shows a potometer with its parts marked. Its functioning is described below: shoot is held in place in the tube using a rubber stopper with a hole. A bubble is introduced into the capillary. The position of the bubble is set at the start of the experiment by turning the tap on the reservoir. The distance the bubble travels in a given time is noted. What does the potometer probably measure?
(a) Oxygen intake by a plant.
(b) Carbon dioxide intake by a plant.
(c) ater intake by a plant.
(d) Effect of water salinity on a plant.

Answer : C

Question. Cell theory states that all organisms are made up of one or more similar units of organization called cells. Which of the following organisms do not strictly adhere to this theory?
(a) protozoa
(b) bacteria
(c) viruses
(d) algae

Answer : C

Question. Which of the following protects the ANIMAL cell from the outside environment?
(a) Cell wall
(b) Plasma membrane
(c) Nuclear membrane
(d) Cytoplasm

Answer : B