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NCERT Solutions for Class 8 Science Chapter 8 Cell Structure and Functions

NCERT Solutions for Class 8 Science Chapter 8 Cell Structure and Functions

Exercises

Question :- 1. Indicate whether the following statements are True (T) or False (F).

(a) Unicellular organisms have one-celled body. (T/F)

(b) Muscle cells are branched. (T/F)

(c) The basic living unit of an organism is an organ. (T/F)

(d) Amoeba has irregular shape. (T/F)

Answer:-

  • (a) True
  • (b) True
  • (c) False
  • (d) True

Question :- 2. Make a sketch of the human nerve cell. What function do nerve cells perform?.

Answer:- Function of Nerve Cells:- The nerve cell’s function is to receive and transmit messages, as well as to help control and coordinate the functions of various parts of the body.

NCERT Solutions for Class 8 Science Chapter 8 Cell Structure and Functions

Question :- 3. Write short notes on the following:

(a) Cytoplasm

Answer:- The cytoplasm is a fluid that contains all of the cell’s organelles, including mitochondria, ribosomes, and Golgi bodies. it can be found  b etween the nucleus and the cell membrane. It helps in the material exchange between cell organelles. It’s mostly transparent and colourless, and it’s made up of 80% water.

(b) Nucleus of a cell

Answer:- The nucleus is found in the centre of the cell.  It is a double-membrane bound cell organelle. It contains the genetic material called DNA. A membrane called the nuclear membrane separates it from the cytoplasm.

 

Question :- 4. Which part of the cell contains organelles?

Answer:- Cytoplasm

 

Question :- 5. Make sketches of animal and plant cells. State three differences between them.

Answer:-

Plant cell

Animal cell

Plant cell are large in size

They are smaller than plant cells

The cell wall is present in Plant cell

The cell wall is absent

Vacuoles are large in Plant cell

Vacuoles are small as compared to Plant cell

Plastids could be seen in Plant cell

Except for Euglena, Plastids could not be seen in animal cells.

Chapter 8 Cell Structure and Functions Class 8 Science

Question :- 6. State the difference between eukaryotes and prokaryotes.

Answer:-

Prokaryotes

Eukaryotes

Most of prokaryotes are unicellular.

Most of eukaryotes are multicellular.

The nucleus is poorly defined as there is no nuclear membrane.

The nucleus is well defined as there is a nuclear membrane present in it.

All the cell organelles are not present.

All the cell organelles are present.

Nucleolus is absent in prokaryotes.

Nucleolus is present in eukaryotes.

Eg: Blue-green algae, Bacteria.

Eg: Plant, Animal cells and Fungi.

Question :- 7. Where are chromosomes found in a cell? State their function.

Answer:- Chromosomes are found in the nucleus. The functions of chromosomes is to carry genes on them and to transfer character from one generation to the next.

Question :- 8. ‘Cells are the basic structural units of living organisms’. Explain.

Answer:-  Different cells combine and form tissues then these tissues combine to form organs. Similarly, all these organs combine to form a body. Thus they are known  as the basic structural unit of every living organism.

Question :- 9. Explain why chloroplasts are found only in plant cells?

Answer:-  Chloroplasts are plastids required for photosynthesis, and thus they are only present in plant cells.

Question :- 10. Complete the crossword with the help of clues given below:

Across

  1. This is necessary for photosynthesis.
  2. Term for component present in the cytoplasm.
  3. The living substance in the cell.
  4. Units of inheritance present on the chromosomes.

Down

  1. Green plastids.
  2. Formed by collection of tissues.
  3. It separates the contents of the cell from the surrounding medium.
  4. Empty structure in the cytoplasm.
  5. A group of cells.
Class 8 Science Chapter 8 Cell Structure and Functions question answer
ncert solutions for class 8 science chapter 8 pdf