Unit 4 – Cells and Tissues (Short Questions)

Q.1. Name some products of cells.

Q.2. Differentiate between magnification and resolution.

Q.3. Who developed the first microscope and what was its magnification power?

Q.4. What are the magnification powers of light and electron microscopes?

Q.5. Give the main principles of cell theory.

Q.6. What are plasmodesmeta? Give their functions.

Q.7. What suggests the presence of DNA & ribosomes in the mitochondria and plastids?

Q.8. What are the functions of smooth Endoplasmic reticulum?

Q.1. Name some products of cells.
Answer:
The hair on our body, finger nails, orange juice, claws, hoofs, horns and wood are the products of cells.

Q.2. Differentiate between magnification and resolution.
Answer:
Magnification and resolution are two different things; magnification is the increase in his apparent size of an object while resolution is the measure of clarity of an image. It is the minimum distance at which two objects can be distinguished as separate objects. Microscope increases magnification and nets the resolution.

Q.3. Who developed the first microscope and what was its magnification power?
Answer:
The first compound microscope was developed by Zacharias Janssen of Holland in 1595. It had a magnification power of 3x 9x.

Q.4. What are the magnification powers of light and electron microscopes?
Answer:
The magnification powers of light and electric microscopes are:
Light Microscope: 1500x
Transmission Electron Microscope (TEM): 250,000x
Scanning Electron Microscope (SEM): 10,000 to 100,000x.

Q.5. Give the main principles of cell theory.
Answer:
The cell theory, in its modern form, includes the following principles:
1. All organisms are composed of one or more cells, within which all life processes occur.
2. Cells are the smallest living things, the basic. unit of organization of all organisms.
3. Cells arise only by divisions in previously existing cells:

Q.6 What are plasmodesmeta? Give their functions.
Answer:
Plasmodesmeta are the cytoplasmic connections between the walls of the neighbouring cells. These are used to transfer materials between the cells.

Q.7. What suggests the presence of DNA & ribosomes in the mitochondria and plastids?
Answer:
The presence of DNA & ribosomes in mitochondria and plastids suggest that they are self-replicated bodies and they were once independent of the cells.

Q8: What are the functions of smooth Endoplasmic reticulum?
Answer:
Smooth endoplasmic reticulum performs the following functions:
(i)     It is involved in lipid metabolism.
(ii)    It transports materials from one part of the all to others.
(iii)   It detoxifies the harmful chemicals.