Biology

The Fundamental Unit of Life

Question:

Why do we stain cells while observing under microscope? List commonly used stains.

Answer:

Stains help us visualize specific organelles of cells in better way. Otherwise these organelles are not easily recognizable via microscope. Stains or dyes are basic or acidic in nature have affinity to certain organelles. For example, methylene blue is a basic dye which has affinity to nucleic acid and hence it can stain nucleus. Methylene blue is commonly used to stain animal cells. Similarly, iodine dye is used to detect starch and used to stain plant cells. Eosin is used to identify RBCs, cell membrane and cytoplasm. Safarnin is another nuclear stain, and also used to stain Rheo leaves to visualize stomata. (Read a nice article on Cell Stain)
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The Fundamental Unit of Life

Q 1.

Who proposed fluid-mosaic model of cell or plasma membrane?

Q 2.

What are chromosomes?

Q 3.

What are the components nucleus?

Q 4.

Name the smallest cell in human body.

Q 5.

Will the temperature have any effect on the process of the osmosis?

Q 6.

When chromosomes are visible in the nucleus?

Q 7.

Name the cell organelles which their own DNA and Ribosomes.

Q 8.

Name the biggest cell in human body.

Q 9.

What is the full form of DNA and RNA?

Q 10.

What are different types transport of components across cell membrane?

Q 11.

What is osmoregulation?

Q 12.

What is diffusion?

Q 13.

Who expanded cell theory by suggesting that all cells arise from pre-existing cells?

Q 14.

Name the cell type that have internal membranes which compartmentalize their functions.

Q 15.

Identify cell organelle and write down its name:
Present in some animal cells, help in locomotion.

Q 16.

Identify cell organelle and write down its name:
Powehouse of cell

Q 17.

Identify cell organelle and write down its name:
A structure involved in production of ribosomes, present inside a nucleus.

Q 18.

Name the world's smallest cell.

Q 19.

Define Osmosis. What are different types of osmosis? Give examples of osmosis.

Q 20.

What is the function of nucleoplasm?

Q 21.

Identify cell organelle and write down its name:
A fluid-filled space surrounded by a membrane. Generally contains salts and sugars in plants.

Q 22.

What are the function of nucleus?

Q 23.

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 24.

Which organ of the plant body helps in osmoregulation?

Q 25.

What is cytoskeleton?

Q 26.

What is plasmolysis?

Q 27.

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 28.

Identify cell organelle and write down its name:
Slipper or oval shaped, its inner membrane is multi-folded and has lot of chemical activity

Q 29.

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 30.

Identify cell organelle and write down its name:
Digestive organelle where macromolecules are hydrolyzed

Q 31.

Identify cell organelle and write down its name:
Detoxify drugs and poisons specially in liver cells.

Q 32.

Define Cell

Q 33.

Who coined the term 'protoplasm'?

Q 34.

Name the longest cell in human body.

Q 35.

Give an example of anucleate cell i.e. cell without nucleus.

Q 36.

What do you mean by Endocytosis? How does an Amoeba obtain its food?

Q 37.

Who is known as Father of Biology?

Q 38.

Who discovered Golgi apparatus?

Q 39.

What is the energy currency of the cell called?

Q 40.

What are centrosomes? What functions do they perform?

Q 41.

Name the cell organelles which change energy from one form to another.

Q 42.

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 43.

Identify cell organelle and write down its name:
Called 'suicide bags' of a cell.

Q 44.

In which year electron microscope was invented?

Q 45.

Name the book in which Robert Hooke published his observations about cork cells.

Q 46.

Who discovered nucleus in the cell?

Q 47.

Name the largest cell?

Q 48.

Give examples of cells which are muti-nucleate (i.e. having many nuclei).

Q 49.

What is the plasma membrane composed of?

Q 50.

Is plasma membrane permeable or selectively permeable?