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The fundamental unit of life | class 9 Science NCERT exercises

CHAPTER - 5

Ans1.
Plant cell
1. It has cell wall.
2. It contain chloroplast.
3. vacuole is large.
4. Nucleus is present in the side of the plant cell.
5. They do not have centriole.

Animal cell
1. They don't have a cell wall.
2. They don't contain chloroplast.
3. Vacuole is small.
4. Nucleus is present at the centre.
5. Centriole is present.

Ans2.
Prokaryotic cell
1. Generally small (1 - 10μm).
2. Nuclear region is poorly defined due to absence of a nuclear membrane known as nucleoid.
3. There is a single chromosome.
4. Membrane bound cell organelles absent.
Eukaryotic cell
1. Generally large (5 - 100μm).
2. Nuclear region well defined and surrounded by a nuclear membrane.
3. There are more than one chromosome.
4. Membrane bound cell organelles present.

Ans3.
If plasma membrane ruptures or breaks down then molecules of some substances will freely move in and out.

Ans4.
Golgi apparatus has the function of storage, modification and packaging of the products in vesicles. If there were no Golgi bodies, packaging and dispatching of materials synthesized by the cell will be stocked.

Ans5.
Mitochondria is known as powerhouse of the cell because it releases the energy required for different activities of life in the form of ATP which is known as the "energy currency of cell".

Ans6.
Lipids and proteins are synthesized in endoplasmic reticulum.

Ans7.
Through the process of endocytosis, amoeba obtain its food. Food particles are engulfed forming a food vacuole girdling it which is assisted by the pseudopodia.

Ans8.
It is the process of movement of water molecules from a region of higher water concentration through a semi permeable membrane to a region of lower water concentration.

EXTRA QUESTIONS

 Q1. What is hypotonic solution?
Ans A solution having solute concentration lower than that of the cell sap is called hypotonic solution.

Q2. What is hypertonic solution?
Ans A solution having solute concentration higher than that of the cell sap is called hypertonic solution.

Q3. What is isotonic solution?
Ans A solution having solute concentration same as that of the cell sap is called isotonic solution.

Q4. Cell wall is made up of which component?
Ans Cellulose.

Q5. Give some examples of unicellular organisms.
Ans Amoeba, Bacteria, Paramecium.

Q6. Give examples of multicellular orgasnisms.
Ans Fungi, Plants, Animals.

Q7. Name the outermost layer found in animal cells.
Ans Plasma membrane.


              by     www.advguruji.blogspot.com
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