Question:
What are centrosomes? What functions do they perform?
Answer:
Centrosome is a small, star shaped protoplamic organelle and is present near to nucleus. In animal cells, it consists of two small granules called centrioles. These centrioles are orthogonally arranged i.e. lie at right angles to each other. In plant cells, centrioles are absent.
Functions of Centrosomes:
- Initiate cell division
- During cell division, centrioles move to opposite poles of the cell and help in spindle formation.
- They form basal bodies (microtubules like sturtures) which form cillia or flagella.
The Fundamental Unit of Life
Q 1.
Who proposed fluid-mosaic model of cell or plasma membrane?
Q 2.
What are chromosomes?
Q 3.
Name the biggest cell in human body.
Q 4.
Identify cell organelle and write down its name:
Present in some animal cells, help in locomotion.
Q 5.
Who expanded cell theory by suggesting that all cells arise from pre-existing cells?
Q 6.
What are the components nucleus?
Q 7.
What is osmoregulation?
Q 8.
Name the cell organelles which their own DNA and Ribosomes.
Q 9.
When chromosomes are visible in the nucleus?
Q 10.
What is the full form of DNA and RNA?
Q 11.
Name the cell type that have internal membranes which compartmentalize their functions.
Q 12.
Identify cell organelle and write down its name:
A fluid-filled space surrounded by a membrane. Generally contains salts and sugars in plants.
Q 15.
Identify cell organelle and write down its name:
A partially permeable layer prevents cell contents from escaping controls what substances enter and leave the cell. Identify?
Q 16.
What is the function of nucleoplasm?
Q 17.
Identify cell organelle and write down its name:
Called 'suicide bags' of a cell.
Q 18.
Who coined the term 'protoplasm'?
Q 19.
Who is known as Father of Biology?
Q 20.
What are centrosomes? What functions do they perform?
Q 21.
Who discovered Virus?
Q 22.
Identify cell organelle and write down its name:
A network of flattened cavities surrounded by a membrane, which links with the nuclear membrane. Help in packaging proteins.
Q 23.
Identify cell organelle and write down its name:
Powehouse of cell
Q 24.
Identify cell organelle and write down its name:
Digestive organelle where macromolecules are hydrolyzed
Q 25.
Name the longest cell in human body.
Q 26.
Which organelle of the cell in animals helps in osmregulation?
Q 27.
Name the cell organelles which change energy from one form to another.
Q 28.
Name the smallest cell in human body.
Q 29.
What are the function of nucleus?
Q 30.
Why is mitochondria absent in red blood cells?
Q 31.
Identify cell organelle and write down its name:
A structure involved in production of ribosomes, present inside a nucleus.
Q 32.
Identify cell organelle and write down its name:
Detoxify drugs and poisons specially in liver cells.
Q 33.
Will the temperature have any effect on the process of the osmosis?
Q 34.
Are there any exceptions to cell theory proposed by Schleiden & Schwann and Virchow? If yes, what are those?
Q 35.
Who proposed the cell theory?
Q 36.
Name the two postulates of the cell theory.
Q 37.
Give examples of cells which are muti-nucleate (i.e. having many nuclei).
Q 38.
What will happen if a de-shelled egg in a concentrated salt solution for 5 minutes?
Q 39.
Put dried raisins in plain water and leave them for some time. Then place them in concentrated solution of sugar or salt. What do you observe in both cases?
Q 40.
Which organ of the plant body helps in osmoregulation?
Q 41.
Are Viruses Prokaryotic or Eukaryotic?
Q 42.
Which cell organelle is called 'transport system'?
Q 43.
Identify cell organelle and write down its name:
Jelly like substance containing particles and other organelles. What is it?
Q 44.
What are different types transport of components across cell membrane?
Q 45.
Define Passive Transport.
Q 46.
Who discovered Golgi apparatus?
Q 47.
Which cell organelle is known as 'protein factory'?
Q 48.
What is the energy currency of the cell called?
Q 49.
What are the conditions for osmosis?
Q 50.
What is cytoskeleton?
