Sunday, 19 June 2016

TEXTBOOK ANSWERS AND SOLUTIONS OF CBSE CLASS VIII SCIENCE Chapter 8 Cell- Structure and functions



1)Indicate whether the following statements are True (T) or False (F).
(a) Unicellular organisms have one-celled body. (T)
(b) Muscle cells are branched. (F)
(c) The basic living unit of an organism is an organ. (F)
(d) Amoeba has irregular shape. (T)

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

ANSWER:-

The function of a nerve cell is to transmit messages to the brain and also to take away messages from the brain to the receptor organs.
3)Write short notes on the following.
(a) Cytoplasm
(b) Nucleus of a cell

ANSWER:- (a) Cytoplasm -It is the jelly-like substance present between the cell membrane and the nucleus. Various other components, or organelles, of cells are present in the cytoplasm. These are mitochondria, golgi bodies, ribosomes, etc.


(b) Nucleus of a cell- It is generally spherical and located in the centre of the cell. Nucleus is separated from the cytoplasm by a membrane called the nuclear membrane. This membrane is also porous and allows the movement of materials between the cytoplasm and the inside of the nucleus.

4)Which part of the cell contains organelles?

ANSWER:- The cytoplasm contains cell contains organelles.

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

ANSWER:-





6)State the difference between eukaryotes and prokaryotes.

ANSWER:-


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

ANSWER:- The nucleus contains thread-like structures called chromosomes. Chromosomes play an important role in the inheritance of characters. They carry genes that help in the transfer of characters from the parents to the offspring.

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

ANSWER:- Cells are the smallest units from which a living organism is made. A cell contains all the necessary structures which are required to carry out various biological processes. A group of cells makes a tissue which further makes organs and finally an organism. Thus, cells are called the basic structural unit of living organisms.

9)Explain why chloroplasts are found only in plant cells?

ANSWER:- Chloroplasts are found only in plant cells. They contain a green pigment called chlorophyll. This green pigment is important for photosynthesis in green plants. This chlorophyll pigment traps solar energy and utilizes it to manufacture food for the
plant.


Written By Badal Paul
The author is a passionate blogger, writer and educationalist. This blog is created to ease troubles of the Cbse students. The author holds multiple blogs and the writer of the Novel KALCHAKRA, OOM AND THE CHOSEN FIVE.