Activity 8.2 Class 8 Science Chapter 8 Solution

Activity 8.2 Class 8 Science Cell- Structure and Functions

In this post, you will find NCERT Science Class 8 Chapter 8 Cell- Structure and Functions Activity solutions. 

You are suggested to study NCERT activity 8.2 class 8 science explanation with a conclusion so that you can attempt questions based on activity 8.2 class 8 science.

Activity 8.2 Class 8 Science

   ·     Boil a hen’s egg. Remove the shell.

   ·     What do you observe?

   ·     A white material surrounds the yellow part.

   ·     White material is albumin which solidifies on boiling.

   ·     The yellow part is the yolk. It is part of the single cell.

   ·     You can observe this single cell without any magnifying device.

     

Observation and explanation 

An egg basically consists of three parts:

1. a shell

2. an egg white

3. an egg yolk

An egg from a hen consists of approximately 2/3 egg white and 1/3 egg yolk.

   1. The shell is built of 8-10,000 pores, which ensures that oxygen can penetrate and CO₂ and other gases can escape. The shell represents about 10 % of the weight of the egg and consists mainly of calcium carbonate and calcium phosphate.

 

   2. The egg white represents approx. 60 % of the weight of the egg and consists of 88 % water and 12 % dry matter, primarily protein. The white is divided into three parts: an inner and an outer liquid layer, and in between those a liquid layer with a thicker consistency. The white prevents external bacteria from penetrating the yolk.

   3. The yolk has a much lower water content than the egg white, just under 50 %. The yolk represents about 28 % of the weight of the egg and consists of approx. 2/3 fat and 1/3 protein. The yolk is held in place by two screw-shaped egg-white strands – the chalazae

Conclusion 

It is concluded that the single cell can be observed without any magnifying device.

Related Topics 

1. Activity 8.1

2. Activity 8.3