Chhattisgarh Board Class 8 Science Chapter 7 Solution

Chhattisgarh Board Class 8 Science Chapter 7 Solution Backpage exercises as well as additioal question and answers from the chapter.

CG Board Class 8 Structural and Functional Unit of our Body – The Cell

 

Choose the correct alternative :-

Cell wall of plant cell is made of :-

• Protein  
• Fats
• Cellulose
• Protein and fat.

 

The power house of the cell is :-

• Centrosome    
• Ribosome
• Nucleus 
• Mitochondria

 

Protein synthesis in the cell is done by :-

• Ribosome       
• Plastids
• Vaculoes
• Nucleus

 

Example of Prokaryotic cells is :-

• Euglena 
• Amoeba
• Paramoecium  
• Blue green algae

 

Nuclear membrane is not present in :-

• Onion cells      
• Bacterial cells
• Inner cheek cells       
• Hydra cells

 

Fill in the blanks.

1. The control room of the cell is …………………[nucleus]
2. The cell was discovered by ……………………….[Robert Hooke]
3. ………..shrinks to form chromosomes.[Chromatin network]
4. In a prokaryotic cell DNA is scattered in the …………………..[cytoplasm]
5. Green colour of plants is due to……………………[chloroplasts]

Match the following.

1. Centrosome     –        carrier of genetic material
2. Protoplasm      –        helps in cell division
3. Endoplasmic reticulum        –        Plasma membrane
4. Semi permeable membrane  –        transport of materials in the cell
5. Chromosomes  –        physical basis of life.

Answers

• Centrosome – helps in cell division
• Protoplasm – physical basis of life
• Endoplasmic reticulum – transport of materials in the cell
• Semi-permeable membrane – Plasma membrane
• Chromosomes – carrier of genetic material

Answer the following questions:-

 

Why is cell called the functional unit of life?

Cell is the smallest structure and functional unit, hence it is called the working unit of life. Every cell performs a function essential for the survival and functioning of living organisms.

 

What is the function of plasma membrane?

The plasma membrane has several functions:

• It helps in maintaining the shape of the cell.
• It controls the flow of different molecules to and fro in the cell.
• It protects and supports the cell.

 

Which structure is there outside the cell membrane in the plant cell and what is it made of?

In plant cells, there is an additional outer covering called the cell wall, which is made of cellulose.

 

Write three differences between plant cell and animal cell.

• Plant cells have a cell wall made of cellulose, while animal cells lack a cell wall.
• Plant cells contain chloroplasts for photosynthesis, whereas animal cells do not have chloroplasts.
• Plant cells often have a large central vacuole, while animal cells have smaller vacuoles or none at all.

 

What is the function of chloroplast?

The function of chloroplasts is to carry out photosynthesis, where they capture sunlight and convert it into chemical energy, producing glucose and oxygen.

 

Why the cells are of different shapes and size ? Give reasons.

Cells come in different shapes and sizes as they are adapted to perform specific functions. Variation in cell shape and size is influenced by their specific roles within tissues and organs. For example, nerve cells are elongated to transmit signals, while red blood cells are biconvex to efficiently transport oxygen. Within the overall structure and function of the organism, the functioning of the cell changes.

 

What is the shape of the cell; rectangular, oval or round?

Cells can have various shapes, including rectangular, oval, or round. The shape of a cell is determined by its function and location in the organism. Cells usually have a definite margin or boundary defined by the plasma membrane.