Biology _Tissue

• Biology
• Secondary Education

Chondrocytes are present in

1. bone
2. ligament
3. cartilage
4. tendon

inner lining of fallopian tube contains

1. Glandular epithelium
2. ciliated epithelium
3. squamous epithelium
4. cuboidal epithelium

Expected Learning Outcome:

Differentiate between simple permanent and complex permanent plant tissues.

Compare different types of simple permanent tissues- parenchyma, collenchyma and sclerenchyma on the basis of their structure, function and location.

Meristematic Tissue

Only certain parts of a plant tend to grow. The tissues located in such parts are called meristematic tissues.

They have the capability to divide themselves and form new tissues. They have thin cell wall made of cellulose. Also have dense nucleus and cytoplasm but lack vacuoles.

They can further we classify differently based on the areas of the plants where they are located -

Apical

Lateral

Intercalary

Apical Meristem

They are responsible for the growth of stems and roots in the plants

They are found on the tips of the roots and stems. 

Lateral Meristem

They are responsible for increasing the circumference of the middle part of the stem and hence are found there.

Intercalary Meristem

These tissues are present at internodes or stem regions between the places at which leaves attach.

Condition: Ravi cut the root tip of onion kept in Jar B

 

Condition: Ravi cut the root tip of onion kept in Jar B
a. Do the roots continue growing Condition: Ravi cut the root tip of onion kept in Jar B
a. Do the roots continue growing even after removal their tips? Why /why not?

Why there are no vacuoles in the intercalary meristem?

Why there are no vacuoles in the intercalary meristem?

Vacuoles are responsible for storage of food in water. The intercalary tissues do not store them. They are rather responsible for manufacturing them.

Moreover, vacuoles contain sap which provides rigidity to a cell. This property of vacuoles may not allow the intercalary tissues to divide and manufacture new cells. Hence vacuoles are not present in them.

HOME FUN

NCERT Pg no-74-Q 3- Q. Which tissue makes up the husk of coconut?

2. Compare types of simple permanent tissue on the basis of structure, location and function.

EXPECTED LEARNING OUTCOME 

Define simple permanent tissue.

Compare different types of simple permanent tissues- parenchyma, collenchyma and sclerenchyma on the basis of their structure, function and location.

Permanent Tissue

The cells that are formed by the meristematic tissues often have to take a certain role in the plant and thus, they lose their ability to divide and form more cells. They then become the permanent tissues of the plants.

Differentiation - The process by which cells of the meristematic tissues convert themselves into a permanent tissue by taking a fixed shape, size and function is called differentiation.

Types of Permanent tissue

Name the regions in which parenchyma tissue is present

Chlorenchyma

These tissues are similar to that of parenchyma but they also contain chlorophyll in them.

Due to the presence of chlorophyll, they are capable of performing the process of photosynthesis in plants.

Aerenchyma

They are found in aquatic plants.

They are also similar in structure to that of the parenchyma but they have large air cavities in them.

These cavities allow the aquatic plants to float in water.

WHAT IS LIGNIN?

• Which tissue in plants provides them flexibility
• What is responsible for increase in girth of the stem or root?

What is epidermis?

Epidermis

The outermost layer of the cell is known as the Epidermis.

It covers the entire plant.

It is a thin layer of single cells but in places with less water, the epidermis of the plants can become thick in order to avoid frequent water loss.

The cells are flat and they have no intercellular spaces between them.

The outer walls of the epidermal cells are thick and the inner walls are thin.

The epidermal cells often have long hair-like structures in roots which facilitate the absorption of water.

.

Stomata

Stomata are pore-like structures that are present in the epidermis of the leaves.

These pores are enclosed by two cells that have a similar shape as a kidney. These are called Guard Cells of Stomata. Guard cells are modified epidermal cells.

Guard cells are responsible for the exchange of gases and transpiration.

Why is epidermis important for the plants?

The epidermis is important for it gives protection against water loss. Epidermal cell present on the aerial parts of the plant often secretes a waxy, water-resistant layer on their outer surface. This provides protection against loss of water, mechanical injury and invasion by parasitic fungi. Epidermal tissue forms a continuous layer which helps to avoid mechanical stress

The husk of coconut is made of which type of permanent tissue?