Important Questions for Chapter-8 Cell -Structure and Functions

Important questions for CBSE Class 8 Science Chapter-8 Cell -Structure and Functions

This page is prepared by the HT experts and consists of all the important questions chapter-wise; you can find important questions for CBSE class 8 science Chapter -8 Cell -Structure and Functions. Chapter-8 Cell -Structure and Functions required a good understanding of the theory so before solving the given questions read the theory given in the NCERT textbook for Chapter -8 Cell -Structure and Functions. Check out the list of chapter-wise Important questions for class 8 science prepared by experts do follow NCERT Solutions for class 8. 

Important Questions for Class 8 Science consists of Subjective Questions of the following Types 

Section-1 It consists of the Most Important Questions from Chapter-8 Cell -Structure and Functions having 5 Marks with solutions

Section-2. It consists of the Most Important Questions from Chapter -8 Cell -Structure and Functions having 3 Marks with solutions

Section-3. It consists of Most Important questions from Chapter -8 Cell -Structure and Functions having 2 & 1 Marks with solutions

Questions based on Name of Chapter– Cell Structure and Functions

Q 1.   What is the basic structural and functional unit of all living organisms and who observed it for the first time? (2 Marks)

Ans.    The basic structural and functional unit of all living organisms is the Cell. It was observed for the first time by Robert Hooke.

Q2.   What are autotrophs? (1 MarksMark)

Ans   The organisms that prepare their food are theautotrophsthe autotrophs. e.g. green plants. 

Q3.    Which organism has the smallest cell? (1 MarksMark)

Ans.   Mycoplasmas, a bacteria has the smallest cell of the size of 0.1 microns i.e. ten-thousandth part of a millimetre.

Q4.   Which is the largest cell visible by the unaided eye? (1Marks)

The egg is the larlarget visited by the cell by the unaided eye.

Q5.    Describe the variations in shape and size of cells(3 Marks)

Ans.  Cells are generally round or spherical. However, they can be cuboidal or columnar and some animal cells are long and branched as in nerve cells.

Size may range from very small which can not be visible to the naked eye and are the order of 0.1 microns e.g. in bacteria, to large and long e.g. muscle cells in animals and fibres in plants. 

Q7.  Write short notes on(5 Marks)

        i) Protoplasm

        ii) Nucleus

Ans.

i) Protoplasm:

This is the membrane-bound liquid substance of a cell. 

Ninety-nine per cent of the protoplasm by weight is made up of the compounds of carbon, hydrogen, nitrogen and oxygen. 

These compounds are mainly water, carbohydrates, proteins, fats, nucleic acids and mineral salts.

ii) Nucleus:

This is the most important part of controlling the activities of living cells. 

In the majority cells, the nucleus lies in the centre, in a few cells it may lay near the periphery as in plant cells.

The main components of the nucleus are nucleoplasm, chromatin and nucleolus. 

Nucleoplasm is the protoplasm of the nucleus enveloped by the nuclear membrane.

Chromatin is the fibrous network of chromosomes containing the genes.

The nucleolus is a round and denser part.

Q.8 Why cells could not be observed before the seventeenth century? (1Marks)

Ans. Cells could not be observed before the seventeenth century because till that time no microscope was invented.

Q.9    Why Hooke had to take thin slices of cork? (1Marks)

Ans. Details of the cork could not be observed if it was thick.

Q.10    Where did Hooke examine cork slices? (1Marks)

Ans.    In Royal Society of London. 

Q.11    Single-celled organisms are also called unicellular organisms (true/false). ( 1Marks)

Ans.   True

Q.12    Name the cells having branch structures. (1Marks)

Ans.   Nerve  Cell.

Q.13    Which cell is observable with the unaided eye? (1Marks)

Ans. Ostrich Egg.

Q.14    Name the outermost layer of an animal cell. (1Marks)

Ans.   Plasma membrane.

Q.15    Mention the layer outside the plasma membrane of a plant cell. (1Marks)

Ans.  Cell Wall.

Q 16. Which four basic elements constitute 90% of protoplasm? (1Marks)

Ans. Carbon, hydrogen, nitrogen and oxygen.

Q.17    Green plastids are also called__________ (1  Marks)

Ans.   Chloroplasts.

Q.18    What do mitochondria do in the cell? (1Marks)

Ans.   Mitochondria are the site of respiration in a cell, generating energy and thus also called the powerhouses of the cell.

Q.19    Name the four elements, which form the major part of protoplasm. (1Marks)

Ans.    These are carbon, hydrogen, oxygen and nitrogen.

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