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.
Name the biggest cell in human body.
Q 3.
What are chromosomes?
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.
Name the cell organelles which their own DNA and Ribosomes.
Q 8.
What is osmoregulation?
Q 9.
Name the cell type that have internal membranes which compartmentalize their functions.
Q 10.
Identify cell organelle and write down its name:
A fluid-filled space surrounded by a membrane. Generally contains salts and sugars in plants.
Q 11.
When chromosomes are visible in the nucleus?
Q 13.
What is the full form of DNA and RNA?
Q 14.
Who discovered Virus?
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 17.
Identify cell organelle and write down its name:
Powehouse of cell
Q 18.
Who is known as Father of Biology?
Q 19.
What are centrosomes? What functions do they perform?
Q 20.
What is the function of nucleoplasm?
Q 21.
Identify cell organelle and write down its name:
Called 'suicide bags' of a cell.
Q 22.
Who coined the term 'protoplasm'?
Q 23.
Why is mitochondria absent in red blood cells?
Q 24.
What is cytoskeleton?
Q 25.
Identify cell organelle and write down its name:
Digestive organelle where macromolecules are hydrolyzed
Q 26.
Identify cell organelle and write down its name:
A structure involved in production of ribosomes, present inside a nucleus.
Q 27.
Name the smallest cell in human body.
Q 28.
Name the longest cell in human body.
Q 29.
Give examples of cells which are muti-nucleate (i.e. having many nuclei).
Q 30.
Which cell organelle is known as 'protein factory'?
Q 31.
Identify cell organelle and write down its name:
Detoxify drugs and poisons specially in liver cells.
Q 32.
What will happen if a de-shelled egg in a concentrated salt solution for 5 minutes?
Q 33.
Will the temperature have any effect on the process of the osmosis?
Q 34.
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 35.
Is plasma membrane permeable or selectively permeable?
Q 36.
What are different types transport of components across cell membrane?
Q 37.
Define Passive Transport.
Q 38.
Why are lysosomes known as suicide bags?
Q 39.
Which organelle of the cell in animals helps in osmregulation?
Q 40.
What are the function of nucleus?
Q 41.
Name the cell organelles which change energy from one form to another.
Q 42.
Identify cell organelle and write down its name:
Jelly like substance containing particles and other organelles. What is it?
Q 43.
Identify cell organelle and write down its name:
Thread like structures made up of in DNA and proteins. Converts to chromosomes when cell is dividing.
Q 44.
In which year electron microscope was invented?
Q 45.
Name the two postulates of the cell theory.
Q 46.
What is the energy currency of the cell called?
Q 47.
What are the conditions for osmosis?
Q 48.
Are Viruses Prokaryotic or Eukaryotic?
Q 49.
Identify cell organelle and write down its name:
Contains green colour pigment, traps light energy. Present in some plant cells.
Q 50.
Identify cell organelle and write down its name:
Controls cell division and cell development.
