Class 8 Science - Chapter Cell - Structure and Functions NCERT Solutions | Write short notes on the following: (a)
Write short notes on the following:
(a) Cytoplasm
(b) Nucleus of a cell
- Cytoplasm: Cytoplasm is a fluid like substance which fills the cell and it is present between the plasma membrane and the nucleus. In cytoplasm, cell organelles like ribosomes, mitochondria and golgi bodies are suspended. Exchange of material between cell organelles is done with the help of cytoplasm.
- Nucleus of a cell: The spherical structure is present in the center of the cell called as nucleus. It is composed of the following components:
- Nuclear membrane: A double layered membrane which separates the contents of the nucleus from the cytoplasm is known as nuclear membrane. Pores that are present in the nuclear membrane which allows the transfer of specific substance in and out of the nucleus.
- Nucleolus: The spherical bodies which are not bounded by a membrane called as nucleolus.
- Chromosomes: The thread like structure which carry genes. Genes have the necessary information for the transfer of different characteristics from parents to the offspring. Therefore, inheritance mainly depends on the chromosomes.
More Questions From Class 8 Science - Chapter Cell - Structure and Functions
- Q:-
Make sketches of animal and plant cells. State three differences between them.
- Q:-
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.
- Q:-
Make a sketch of the human nerve cell. What function do nerve cells perform?
- Q:-
Explain why chloroplasts are found only in plant cells?
- Q:-
Where are chromosomes found in a cell? State their function.
- Q:-
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) - Q:-
‘Cells are the basic structural units of living organisms’. Explain.
- Q:-
State the difference between eukaryotes and prokaryotes.
- Q:-
Which part of the cell contains organelles?
Popular Questions of Class 8 Science
- Q:-
Which of the following can be beaten into thin sheets?
(a) Zinc (b) Phosphorus (c) Sulphur (d) Oxygen - Q:-
Fill in the blanks
(a) Most liquids that conduct electricity are solutions of , ______________ and ______________.
(b) The passage of an electric current through a solution causes ______________ effects.
(c) If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the terminal of the battery.
(d) The process of depositing a layer ofany desired metal on another material by means of electricity is called . - Q:-
Give two examples each of situations in which you push or pull to change the state of motion of objects.
- Q:-
Fill in the blanks:
(a) Friction opposes the _____________ between the surfaces in contact with each other.
(b) Friction depends on the _____________ of surfaces. (c) Friction produces __________.
(d) Sprinkling of powder on the carrom board ________ friction.
(e) Sliding friction is ___________ than the static friction. - Q:-
List conditions under which combustion can take place.
- Q:-
Which of the following cannot be charged easily by friction?
(a) A plastic scale
(b) A copper rod
(c) An inflated balloon
(d) A woollen cloth. - Q:-
Fill in the blanks:
(a) A place where animals are protected in their natural habitat is called .
(b) Species found only in a particular area is known as .
(c) Migratory birds fly to far away places because of changes. - Q:-
Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room. Explain.
- Q:-
What are the different ways in which water gets contaminated ?
- Q:-
Explain the importance of reproduction in organisms.
Recently Viewed Questions of Class 8 Science
- Q:-
Name three liquids, which when tested in the manner shown in Fig.14.9, may cause the magnetic needle to deflect.
- Q:-
Give reasons:
(a) Water is not used to control fires involving electrical equipment.
(b) LPG is a better domestic fuel than wood.
(c) Paper by itself catches fire easily whereas a piece of paper wrapped around an aluminium pipe does not. - Q:-
Word game : Use the clues to work out the words.
Across
3. Protruding voice box in boys
4. Glands without ducts
7. Endocrine gland attached to brain
8. Secretion of endocrine glands
9. Pancreatic hormone
10. Female hormoneDown
1. Male hormone
2. Secretes thyroxine
3. Another term for teenage
5. Hormone reaches here through blood stream
6. Voice box
7. Term for changes at adolescence
- Q:-
Match items in column A with one or more items in column B:
A B
(i) Inner planets (a) Saturn
(ii) Outer planets (b) Pole Star
(iii) Constellation (c) Great Bear
(iv) Satellite of the Earth (d) Moon
(e) Earth
(f) Orion
(g) Mars - Q:-
What is the term used for secretions of endocrine glands responsible for changes taking place in the body?
- Q:-
Give two examples of situations in which applied force causes a change in the shape of an object.
- Q:-
Name two objects other than planets which are members of the solar system.
- Q:-
Does pure water conduct electricity? If not, what can we do to make it conducting?
- Q:-
Prepare a Table having two columns depicting names of endocrine glands and hormones secreted by them.
- Q:-
Discuss the effects of deforestation on the following:
(a) Wild animals
(b) Environment
(c) Villages (Rural areas)
(d) Cities (Urban areas)
(e) Earth
(f) The next generation
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