Histology and life Process || Class 9 Science Notes

Histology and life Process

1. Short answer type question.                          

a. What is a cell?                                                   

= The cell is a structural and functional unit of line.

b. What is the meristematic tissue?                

→ The group of young cells which have the capacity of active cell division is called a meristematic tissue.

c. Define plant tissue.                                            

= A group of plant cells performing essentially the group same function and common to similar shape and size is called a plant tissue.

d. What is a simple permanent tissue?            

= A simple permanent tissue are concerned with. manufacture and storage of food and. providing supports to plants

e. Define a complex permanent tissue.              

= Answer will come soon...                                   

f. What is the function of xylem?                   

→ The function of xylem is to conducts water and minerals from the root to the leaves.

g. Write the function of phloem.                       

= The function of phloem is to transportation of food from leaves to different parts of plants.

h. Name the tissue whose cells are arranged basement membrane.                                         

= Epithelial tissue cells are arranged on the arranged on the basement membrane.

i. Write the function of dendriestes.                  

= The function of dendrites is to receive impulses mostly from the axon of another neuron.

j. Which epithelium forms the inner wall of the blood vessel?

= Pavement epithelium forms the inner wall of the blood vessel.

k. Which connective tissue forms the bridge of the nose?                                                            

= Cartile of hard/dense connective tissue forms the bridge of the nose.                              

l. In which animal tissue matrix be hard?

= Answer will come soon...

m. Which muscle cell is multinucleated?       

= Skeletal muscle cell is multinucleated.          

2. Long answer type type questions: 

a. Why is a cell known as a structural and functional unit of life?

= A cell is capable of carrying out all life processes and all the living beings are made up of cells.. Hence, a cell is known as a structural and functional unit of life.

b. Write in short about apical and lateral meristems.

= *Apical meristems 

- The meristems which are present in the growing points i.e apices of the root and the shoot are called apical meristems. They help plants to increase. their height.

* Lateral meristem 

- These meristem are embedded in the permanent tissues and laterally located eg, cork, cambium of the roots and the stems. They help Plants to increase then girth or diameter.      

c. Mention the types of plant tissues with their major functions.

= The types of plant tissues are:

* Meristematic tissue

- The group young cells which have the capacity of active cell division is called. a meristematic tissue or meristem. The major function of this tissue is to help in growth.

* Permanent tissue

- Answer will come soon empty at least 5 lines.

d. Write in short about parenchyma and sclerenchyma. 

= * Parenchyma

Parenchyma consists of thin-walled living cells. The cells are usually oval or spherical. Those parenchyma cells which contains chloroplast are called chlorenchyma The main function of parenchyma is to manufacture and store food.

* Sclerenchyma

- Sclerenchyma consists of dead cells with a thick cell. wall. It is mainly responsible for providing strength and _mechanical support. It includes fibres and sclereids cells The major functions of this tissue is to saves. the plant from various environmental forces like strong wind, etc.

e. Describe different types of special permanent tissues in short.

= *Parenchyma 

→ Parenchyma consists of thin-walled living cells. The cell. are usually oval or spherical. Those parenchyma cells. which contain chloroplast are called chlorenchyma. The main function of parenchyma is to maintain manufacture and store food. 

* Collenchyma

- Collenchyma has a thick cell wall with an extra deposition of cellulose of the corners of the cells. It is present in the outer regions of the cortex e.g. stem midrib of leaves, petioles, etc. The major function of collenchyma is to provides support and elasticity.

* Sclerenchyma 

- Sclerenchyma consists of dead cells with a thick cell wall. It is mainly responsible for providing strength and mechanical support. It includes fibres and sclereids cells. The major function of sclerenchyma is to save the plant from various environmental forces like strong wind, etc.

f. Write a short note on different types of connective tissue.

= Proper/Loose connective tissue: Loose connective tissue is composed of irregular cells scattered and embedded in a soft matrix. It covers all internal organs and body cavities. It acts as a binding and supporting structure within the body. 

Hard/Dense connective tissue: Dense connective tissue has cell inside some cases called lacune which are scattered in hard matrix It connects different tissues in the body and provides mechanical strength.

Fluid connective tissue: Fluid connective tissue have liquid matrix which are present throughout the body. It provides nutrition, helps in internal transportation and prevents from diseases.

g. Describe epithelial tissues in brief. 

= In epithelial tissues, the cells are attached to the. basement membrane at one margin. The cells face either towards a body fluid or outside the environment. Thus the tissue provides a covering of external and internal organs or lining of cavities. The cells of this tissue are compactly packed and have a very thin layer of inter-cellular matrix They may consist of single layer (simple epithelium) or many layers of cells (compound epithelium). The major functions of this tissue ore protection secretion excretion and absorption.

h. How are cells, tissue and organs interrelated? 

→ Organs is made of up a tissue and tissue is made by cell and cells is structural and functional unit of life of the body system cells tissue and organs are constitute by the body. of all organism. So cells, tissue and organs are interrelated.

i. Explain parenchyma with the help of a neat and labeled diagram.

→ Parenchyma consist of thin-walled living cells. The cells. are usually oval or spherical. Those parenchyma cells. which contain chloroplast are called chlorenchyma The main function of parenchyma is to manufacture and store food. 

j. Describe the structure of neuron with a suitable. diagram in short.

= Neural tissue consists of elongated cells called neurons. A neuron consists of three major parts: the cell body, the axon and the dendrites. The cell body is round in shape and it is the centre of receiving and sending nerve impulses.                     

4. Give reasons 

a. The height of a plant does not increase when its tip is cut-off.

→ Because apical meristem is present at the tip of plant and helps plants to increase their height..

b. A kind of milk-like substance comes out when we pluck a leaf of a rubber plant.

→ Because this kind of milk-like substance or rubber plant are thin walled, elongated and branched ducts. which contains a milky-juice and matrix of watery base wide it.

c. Xylem and phloem collectively called conducting tissue.

→ Because xylem conduct the flow of water and mineral from the rest to the leaves and phloem conduct the flow. of food face the leaves to other parts.