NCERT Solutions for Class 8th Science

Chapter 8 – CELL: STRUCTURE AND FUNCTIONS

(Complete Downloadable Chapter Solution PDF file is at the bottom of the page)

 

Q.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)

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

           (b) Muscle cells are branched. (F)

           Correct: Muscle cells are spindle shaped.

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

           Correct: The basic living unit of an organism is cell.

           (d) Amoeba has irregular shape. (T)

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

Q.3      Write short notes on the following:

           (a) Cytoplasm

           (b) Nucleus of a cell

Ans    (a) Cytoplasm: It is the jelly-like substance present between the cell membrane and the nucleus. Various              other components, or organelles, of cells like mitochondria, golgi bodies, ribosomes, etc. are suspended in            the cytoplasm. It helps in intercellular as well as intracellular exchange of substances.

           (b) Nucleus of a cell: It is generally spherical and located in the centre of the cell. It can be stained and                  seen easily with the help of a microscope. It has following 

Q.4      Which part of the cell contains organelles?

Ans     Cytoplasm

Q.5      Make sketches of animal and plant cells. State three differences between them.

Q.6      State the difference between eukaryotes and prokaryotes.

Q.7      Where are chromosomes found in a cell? State their function.

Q.8      ‘Cells are the basic structural units of living organisms’. Explain.

Ans     The cell in a living organism is the basic structural unit as it is the smallest living part of an organism                 i.e. an organ (group of which makes an organism) is made up of tissues which in turn, are made up of                 cells and each living cell perform certain basic functions like respiration, obtaining nutrition, clearing of             waste material etc that are characteristic of all living forms. In other words, cells are the building blocks             of life. The shape and size of cells varies and are related to the specific function they perform.

Q.9      Explain why chloroplasts are found only in plant cells?

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

Across

1. This is necessary for photosynthesis.

3. Term for component present in the cytoplasm.

6. The living substance in the cell.

8. Units of inheritance present on the chromosomes.

Down

1. Green plastids.

2. Formed by collection of tissues.

4. It separates the contents of the cell from the surrounding medium.

5. Empty structure in the cytoplasm.

7. A group of cells.