NIOS Class 10 Science and Technology Chapter 21. BUILDING BLOCKS OF LIFE — CELL AND TISSUES– Chapter-wise Important Questions and Answers

NIOS Class 10 Science and Technology Chapter 21. BUILDING BLOCKS OF LIFE — CELL AND TISSUES | MCQs, Short & Long Answer Questions | 21. BUILDING BLOCKS OF LIFE — CELL AND TISSUES

Chapter 21. BUILDING BLOCKS OF LIFE — CELL AND TISSUES

INTEXT QUESTIONS 21.1

1. Mention whether the following statements are true (T) or false (F). Rewrite the wrong statements correctly.

i) Cell membrane permits inflow and outflow of all molecules. T/F

ii) Chloroplast and not chlorophyll is an organelle. T/F

iii) Ribosomes are often called suicide bags. T/F

Answer: (i) Cell membrane permits inflow and outflow of all molecules. → False
[ Cell membrane permits inflow and outflow of selected substances only (it is selectively permeable).]

(ii) Chloroplast and not chlorophyll is an organelle. → True
[ Chloroplast is a cell organelle, while chlorophyll is the green pigment present inside chloroplast.]

(iii) Ribosomes are often called suicide bags. → False
[ Lysosomes are often called suicide bags of the cell because they contain digestive enzymes.]

2. Name the part of the cell which:

(i) provides rigidity to the plant cell. _____________

(ii) bounds semi-fluid content of the cell. _____________

(iii) helps in intra-cellular distribution of molecules, enzymes and nutrients within the cell. _____________

Answer: (i) Provides rigidity to the plant cell → Cell wall.

(ii) Bounds semi-fluid content of the cell → plasma membrane (Cell membrane).

(iii) Helps in intra-cellular distribution of molecules, enzymes and nutrients within the cell →Cytoplasm.

3. Match the following items in Column A with those in Column B.

                Column A                            Column B

1. Master of the cell                       a. chloroplast

2. Powerhouse of the cell             b. endoplasmic reticulum

3. Protein factories of the cell      c. mitochondria

4. Kitchen of the cell                      d. nucleus

5. Circulatory system of the cell  e. ribosome

Answer: The correct matching is:

Column A	Column B
1. Master of the cell	d. Nucleus
2. Powerhouse of the cell	c. Mitochondria
3. Protein factories of the cell	e. Ribosome
4. Kitchen of the cell	a. Chloroplast
5. Circulatory system of the cell	b. Endoplasmic reticulum

4. All cells of organisms have 3 basic parts. Draw and name them.

Answer: Photo

5. Explain in your own words the three salient points of the cell theory in one sentence each.

Answer: The three salient points of the cell theory are:

(i) Body of all the living organisms are made of cells.

(ii) New cells arise by division of pre-existing cells.

(iii) Function of the body rebuilt from functions of its cells.

INTEXT QUESTIONS 21.2

1. A seedling grows into a small plant. What kind of division causes this — mitosis or meiosis?

Answer: A seedling grows into a small plant by mitosis.

2. Our nails have to be cut occasionally. Which kind of cell division makes the nails long?

Answer: Our nails become long due to mitosis.

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