ch :-2 CELL
EXERCISE
1. Who
discovered cells and how?
Answer
An English Botanist, Robert Hooke discovered cells. In 1665, he used self-designed microscope to observe cells in a cork slice.
2. Why is the cell called the structural and functional unit of life?
Answer
Cells are called the structural and functional unit of life because all the living organisms are made up of cells and also all the functions taking place inside the body of organisms are performed by cells.
1. Make a comparison and write
down ways in which plant cells are different from animal cellsAnswer
An English Botanist, Robert Hooke discovered cells. In 1665, he used self-designed microscope to observe cells in a cork slice.
2. Why is the cell called the structural and functional unit of life?
Answer
Cells are called the structural and functional unit of life because all the living organisms are made up of cells and also all the functions taking place inside the body of organisms are performed by cells.
3. What would happen if the plasma membrane ruptures or breaks down?
Answer
If the plasma membrane ruptures or breakdown then the cell will not be able to exchange material from its surrounding by diffusion or osmosis. Thereafter the protoplasmic material will be disappeared and the cell will die.
4. What would happen to the life of a cell if there was no Golgi apparatus?
Answer
Golgi apparatus has the function of storage modification and packaging of the products. If there is no Golgi apparatus then the packaging and transporting of materials synthesized by cell will not happen.
5. Which organelle is known as the powerhouse of the cell? Why?
Answer
Mitochondria are known as the powerhouse of cells because energy required for various chemical activities needed for life is released by mitochondria in the form of ATP (Adenosine triphosphate) molecules.
6. Where do the lipids and proteins constituting the cell membrane get synthesized?
Answer
Lipids are synthesized in Smooth endoplasmic reticulum (SER) and the proteins are synthesized in rough endoplasmic reticulum (RER).
7. How does an Amoeba obtain its food?
Answer
Amoeba takes in food using temporary finger-like extensions of the cell surface which fuse over the food particle forming a food-vacuole as shown in figure. Inside the food vacuole, complex substances are broken down into simpler ones which then diffuse into the cytoplasm. The remaining undigested material is moved to the surface of the cell and thrown out.
8. What is osmosis?
Answer
Osmosis is the process in which water molecules moves from the region of high concentration to a region of low concentration through a semi permeable membrane.
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