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Biology – Cell Class VI

VERY SHORT QUESTION

1)    Who discovered the presence of cell?

Ans. Antoni Van Leeuwenhoek.

2)    Who coined the term “Cell”?

Ans. Robert Hooke.

3)   Name one cell which is irregular shaped.

Ans. White blood cell.

4)   Name the largest cell in the world.

Ans. Ostrich egg.

5) What is tonoplast?

Ans. Membrane covering vacuole is called tonoplast.

6) Why is Rough Endoplasmic reticulum named so?

Ans. Rough endoplasmic reticulum contains ribosome which synthesises protein that is why it is named so.

7) Which of the following is not true?

a) Living cells are made up of cells.

b) The cell is the structural unit of life.

c) The cell membrane is impermeable.

d) The cell is the functional unit of life.

Ans. c) The cell membrane is impermeable.

8) What is the function of Nucleus?

Ans. To Control all cellular activities.

9) What is the function of Centrosome?

Ans. Centrosome helps in cell division.

FILL IN THE BLANKS

1)Chlorophyll is stored in _____.

Ans. Chloroplast.

2) Amoeba form ____ to store food.

Ans. Food Vacuole.

SHORT QUESTION

1)  Why is the cell called structural and functionalunit of life?

Ans. All living beings are made of cells. The cell is the smallest thing that has life and can exist on its own. That is why cell is called structuraland functional unit of life.

2)  What are the functions of cell membrane?

Ans. Cell membrane is a semipermeable membrane so it allows some selective materials to enter into the cell and someselective substances to exit from the cell.

Cell membrane protects protoplasm.

3)  Name the organelle which is having different shape and size in plant and animal cell.

Ans. Vacuole is present in both plant cell andanimal cell but it larger in size in plant celland smaller in size in animal cell.

4)  What is the difference between plant cell and animal cell in various characters?

Characters Plant cell Animal cell
i)    Cell wall        Present Absent
ii)   Chloroplast       Present        Absent
iii)  Centrosome        Absent        Present
iv)   Vacuole       Large in size       Smaller in size

5)  What is cytoplasm?

Ans. The cell is a tiny sac containing semifluidsubstance. This watery fluid like substance with various salts and proteins is called cytoplasm.

6)   What is the covering of cell?

Ans. Cell is covered by a thin membrane called cellmembrane or plasma membrane.

7)   Name two organelles performing energy transfer.

Ans. Chloroplast to absorb energy by photosynthesis Mitochondria to releaseenergy by respiration.

8)  What is known as “Power house of the cell”? Why?                                                                      Ans. Mitochondria is known as power house of the cell because food is broken down to release energy inside the mitochondria.

9)  What is known as “kitchen of the cell”? why?

Ans. Chloroplast is known as kitchen of the cell.Because photosynthesis and food preparation are taken place inside the chloroplast.

10)  What is cell wall?

Ans. Plant cell has another membrane outside the cell membrane which is called cell wall.

11)  What is cell sap?

Ans. Vacuoles contain a fluid containing water, sugar, salts, other food materials waste materials etc which is called cell sap.

12)  What is plastid?

Ans. Organelle found only in plant cell containingpigment or food material is known as plastid.

13)  What are different types of plastid?

Ans. Plastid is classified into three types: – a) Chloroplast; b) Chromoplast; c) Leucoplast.

14)  What are the characteristics of plastid?

Ans. Plastid is a double membrane organelle. It’s shape varies from round to filamentous.

15)  What is protoplasm?

Ans. Living material inside cell including cytoplasmand nucleus is called protoplasm.

LONG QUESTION / ANSWER

1)  What are the functions of the cell wall?

Ans. Cell wall performs following functions: –

i) It provides definite shape of the cell.

ii) As it is freely permeable so it allows allsubstances to enter and leave the cell whichhelps in absorption of water from soil.

iii) It makes the cell rigid.

iv) It protects the cell from injury.

2)  State various structures of a nucleus.

Ans. Nucleus has main four structures-

i) Nuclear membrane: Nucleus is enclosed bythis membrane.

ii) Nucleoplasm: Nucleus is filled by this semifluid substance.

iii) Nucleolus: It is a small spherical body.

iv) Chromatin: It is a fine threadlike structure arranged in a network.

3) Differentiate between chloroplast, chromoplastleucoplast.

 Ans.

Character Chloroplast Chromoplast Leucoplast
Colour Green Yellow or Red Colourless
Function Photosynthesis Impartcolourtofruit&flower Storageoffood

4) What are the functions of vacuole?

Ans. Functions of vacuole are:

a) It maintains the shape of the cell.

b) It maintains the balance of water in the cell

c) It stores chemicals, food, water and salts.

d) It stores waste products sometimes.             

5) How do multicellular organisms grow?

Ans. The life of higher organisms starts from a single cell, called zygote, which is formed by the function of a male cell and female cell. The single cell divides into two cells, two cells into four cells and so on. In this way the zygote grows into an embryo, the embryo into a baby and the baby into an adult.

6) How do unicellular organisms reproduce?

Ans. In the case of unicellular organisms, the cell comprising the body divides into two to form two organisms. Each of the organism gives rise to two new organisms, and so on.

7) How does skin mend when we get a cut.

Ans. New cells formed by cell division constantly replace dead and damaged cells. In this way skin itself heals the wound and mends when we get a cut.

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