Question:
Are there any exceptions to cell theory proposed by Schleiden & Schwann and Virchow? If yes, what are those?
Answer:
Yes there are exceptions to cell theory. These are:
- Cell theory do not explain nature of Virus. They become live and multiply though they are made up of non-living material.
- How come the first living cell originated or how life began on the earth. (Scientists J.B.S. Haldane, Stanley L. Miller and Harold C. Urey did experiments to on this.).
- Mitochondria and chloroplasts have their own genetic material and can reproduce independently.
The Fundamental Unit of Life
Q 1.
What is the plasma membrane composed of?
Q 2.
Which cell organelle is known as 'protein factory'?
Q 3.
What is the full form of DNA and RNA?
Q 4.
Identify cell organelle and write down its name:
A tough, non-living layer, it prevents plant cells from bursting, freely permeable
Q 5.
Why is mitochondria absent in red blood cells?
Q 6.
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 8.
Which of the following cell is better candidate to study lysosomes?
(a) White Blood Cell
(b) Muscle Cell
Q 9.
Is plasma membrane permeable or selectively permeable?
Q 10.
Name the sac like structure which form the grana?
Q 11.
What are chromosomes?
Q 12.
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 13.
Are plastids present in all cells? What are its types?
Q 14.
Which cell organelle is called 'kitchen of plant'?
Q 15.
Identify cell organelle and write down its name:
Digestive organelle where macromolecules are hydrolyzed
Q 16.
Name the two postulates of the cell theory.
Q 17.
Who coined the term 'protoplasm'?
Q 18.
Place a de-shelled egg in water for five minutes. What do you observe? (Note: De-shelled egg means,the shell of an egg is removed by dissolving it in dilute hydrochloric acid. The shell is mostly calcium carbonate. A thin outer skin now encloses the egg.)
Q 19.
What are the function of nucleus?
Q 20.
Who expanded cell theory by suggesting that all cells arise from pre-existing cells?
Q 21.
Name the smallest cell in human body.
Q 22.
Name the biggest cell in human body.
Q 23.
Which organ of the plant body helps in osmoregulation?
Q 24.
Name the cell type that have internal membranes which compartmentalize their functions.
Q 25.
Identify cell organelle and write down its name:
Jelly like substance containing particles and other organelles. What is it?
Q 26.
Identify cell organelle and write down its name:
Present in some animal cells, help in locomotion.
Q 27.
Identify cell organelle and write down its name:
Called 'suicide bags' of a cell.
Q 28.
Who observed the cells the first time?
Q 29.
Who proposed the cell theory?
Q 30.
In which year electron microscope was invented?
Q 31.
Give examples of cells which are muti-nucleate (i.e. having many nuclei).
Q 32.
When chromosomes are visible in the nucleus?
Q 33.
What are the conditions for osmosis?
Q 34.
Which cell organelle is called 'transport system'?
Q 35.
What is the function of nucleoplasm?
Q 36.
Identify cell organelle and write down its name:
Contains green colour pigment, traps light energy. Present in some plant cells.
Q 37.
Who discovered nucleus in the cell?
Q 38.
Give an example of anucleate cell i.e. cell without nucleus.
Q 39.
Give an example of cells containing two nuclei (Binucleate).
Q 40.
What are different types transport of components across cell membrane?
Q 42.
Who is known as 'Father of Microscopy'?
Q 43.
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 44.
Identify cell organelle and write down its name:
A fluid-filled space surrounded by a membrane. Generally contains salts and sugars in plants.
Q 45.
Who proposed fluid-mosaic model of cell or plasma membrane?
Q 46.
Who is known as Father of Biology?
Q 47.
What are the functions of Endoplasmic Reticulum (ER)?
Q 48.
What is cytoskeleton?
Q 49.
Name the cell organelles which change energy from one form to another.
Q 50.
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.
