Question:
What is diffusion?
Answer:
Diffusion is the net movement of molecules from high to regions of lower concentration as a result of random molecular motion. Diffusion tends to distribute molecules uniformly. Exchange of gases like CO2 and O2 in lungs, plants, blood cells, O2 entering stomata of leaves are examples of diffusion. Diffusion is passive transport i.e. no external energy is provided for the movement of molecules. The natural kinetic energy of the particle supplies the energy.
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.
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 6.
Why is mitochondria absent in red blood cells?
Q 7.
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.
Are plastids present in all cells? What are its types?
Q 11.
Name the sac like structure which form the grana?
Q 12.
Which cell organelle is called 'kitchen of plant'?
Q 13.
What are chromosomes?
Q 14.
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 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.
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 18.
Who coined the term 'protoplasm'?
Q 19.
What are the function of nucleus?
Q 20.
Identify cell organelle and write down its name:
Jelly like substance containing particles and other organelles. What is it?
Q 21.
Who expanded cell theory by suggesting that all cells arise from pre-existing cells?
Q 22.
Name the cell type that have internal membranes which compartmentalize their functions.
Q 23.
Identify cell organelle and write down its name:
Present in some animal cells, help in locomotion.
Q 24.
Name the smallest cell in human body.
Q 25.
Name the biggest cell in human body.
Q 26.
Which organ of the plant body helps in osmoregulation?
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.
Who proposed fluid-mosaic model of cell or plasma membrane?
Q 33.
When chromosomes are visible in the nucleus?
Q 34.
What are the conditions for osmosis?
Q 35.
Which cell organelle is called 'transport system'?
Q 36.
What is the function of nucleoplasm?
Q 37.
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 38.
Identify cell organelle and write down its name:
Contains green colour pigment, traps light energy. Present in some plant cells.
Q 39.
Who discovered nucleus in the cell?
Q 40.
Give an example of anucleate cell i.e. cell without nucleus.
Q 41.
Give an example of cells containing two nuclei (Binucleate).
Q 42.
What are different types transport of components across cell membrane?
Q 44.
Who is known as 'Father of Microscopy'?
Q 45.
What are the functions of Endoplasmic Reticulum (ER)?
Q 46.
Identify cell organelle and write down its name:
A fluid-filled space surrounded by a membrane. Generally contains salts and sugars in plants.
Q 47.
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 48.
What will happen if a de-shelled egg in a concentrated salt solution for 5 minutes?
Q 49.
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 50.
Who is known as Father of Biology?
