NCERT Solutions Class 9 Science Tissues

NCERT Solutions Class 9 Science Tissues

 

INTEXT QUESTIONS AND ANSWERS

Page No. 69

Q1. Define tissue.
Ans.
The tissue is defined as a group of cells which are similar in structure and work together to perform a particular function is known as tissue.

Q2. What is the utility of tissues in multicellular organisms?
Ans. Tissues provide structural strength, mechanical strength, show division of labour.

Page No. 74

Q1. Name types of simple tissues.
Ans. The types of simple tissues are parenchyma, collenchyma, sclerenchyma and aerenchyma.

Q2. Where is apical meristem found?
Ans. Apical meristem is found at the tip of root or shoot of the plant.

Q3. Which tissue makes up the husk of coconut?
Ans. The husk of coconut is made of sclerenchymatous tissue.

Q4. What are the constituents of phloem?
Ans. Phloem is made up of four types of elements sieve tube, companion cells, phloem fibres and phloem parenchyma.

Page No . 78

Q1. Name the tissue responsible for movement in our body.
Ans. 1. Muscular tissue, 2. Nervous tissue, a combination of both the tissues are responsible for movement in our body.

Q2. What does a neuron look like?
Ans. A neuron consists of a cell body with a nucleus and cytoplasm, from which long thin hair like parts arise. Each neuron has a single long part called the axon, and many small, short branched parts called dendrite. An individual nerve cell is called neuron, it may be up to a metre long.

Q3. Give three features of cardiac muscles.
Ans. Feature of cardiac muscles
(1) Heart muscles (cardiac muscles) are cylindrical, branched and uninucleated
(2) They are striated muscle fibres.
(3) They are involuntary muscles, cannot be controlled by us.

Q4. What are the Junctions of areolar tissue?
Ans. Areolar tissue are connective tissues found in animal. It is found between skin and muscles, around blood vessels and nerves and in the bone marrow.
It fills the space inside the organs, supports internal organs and helps in the repair of tissues.

EXERCISES

Q1. Define the term “tissue”.
Ans. Group of cells that are similar in structure and perform same function is called a tissue.

Q2. How many types of elements together make up the xylem tissue? Name them.
Ans. The xylem is made up of vessels, trachieds, xylem fibres and xylem parenchyma.

Q3. How are simple tissues different from complex tissues in plants?
Ans. Simple tissues are made up of one type of cells which coordinate to perform a common function.
Complex tissues are made up of more than one type of cells. All these coordinate to perform a common function.

Q4. Differentiate between parenchyma, collenchyma and sclerenchyma on the basis of their cell wall.
Ans. Parenchyma: The cells have thin cell walls made up of cellulose. Collenchyma: The cells have cell walls thickened at the comers due to pectin deposition.
Sclerenchyma: Their walls are thickened due to lignin deposition.

Q5. What are the functions of stomata?
Ans. The outermost layer of the cell is called epidermis and is very porous. These pores are called stomata. These stomata help in transpiration and exchange of gases.

Q6. Diagrammatically show the difference between the three types of muscle fibres.
Ans. Striated muscles
(1) They are connected to bones (Skeletal muscles).
(2) They are voluntary muscles.
(3) The cells are long, cylindrical with many nuclei and are unbranched.

Smooth muscles
(1) They are found in the alimentary canal and lungs.
(2) They are involuntary muscles.
(3) They are spindle in shape and have a single nucleus.

Cardiac muscles
(1) They are found in the heart.
(2) They are involuntary in action.
(3) They are branched and have one nucleus.

Q7. What is the specific function of the cardiac muscle?
Ans. (1) Cardiac muscles cells are cylindrical, branched and uninucleated.
(2) They are involuntary muscles.
(3) They show rhythmically contraction and relaxation throughout life.
(4) Their rhythmic contraction and relaxation help in pumping action of the heart.

Q8. Differentiate between striated, unstriated and cardiac muscles on the basis of their structure and location in the body.
Ans.

Character Striated muscles Un-striated muscles Cardiac muscles
Shape Long, cylindrical, nontapering.

They are unbranched.

Long and tapering.

They are unbranched.

Cylindrical and nontapering.

They are branched.

Location in body Hands, legs and skeletal muscles Wall of stomach, intestine, ureter and bronchi Heart
Dark and light bands Present Absent Present but less prominent

 

Q9. Draw a labelled diagram of neuron.
Ans.
10

Q10. Name the following:
(1) Tissue that forms the inner lining of our mouth.
(2) Tissue that connect muscle to bone in humans.
(3) Tissue that trar-carts food in plants.
(4) Tissue that siwea j’ut in our body.
(5) Connective tissue with a fluid matrix.
(6) Tissue present in the brain.
Ans. (1) Squamous epithelium (2) Tendons
(3) Phloem (4) Areolar tissue
(5) Blood (6) Nervous tissue

Q11. Identify the type of tissue in the following: Skin, bark of tree, bone, lining of kidney tubule, vascular bundle.
Ans. (a) Skin—Striated squamous epithelium
(b) Bark of tree—Cork, protective tissue
(c) Bone—Connective tissue
(d) Lining of kidney tubule—Cuboidal epithelium tisse
(e) Vascular bundle—Conducting tissue

Q12. Name the regions in which parenchyma tissue is present.
Ans. In the pith of the roots and stems. When it contains chlorophyll, it is called chlorenchyma, found in green leaves. In aquatic plants, parenchyma contains large air cavities and help them to float. Such type of parenchyma is called aerenchyma.

Q13. What is the role of epidermis in plants?
Ans. Cells of epidermis forms a continuous layer without intercellular spaces. It protects all the parts of plants.

Q14. How does the cork act as a protective tissue?
Ans. Cork acts as a protective tissue because its cells are dead and compactly arranged without intercellular spaces. They have deposition of suberin on the walls that make them impervious to gases and water.

Q15. Complete the table:

3

 

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