Who discovered cells and how?
Why is the cell called the structural and functional unit of life?
Why is plasma membrane called a selectively permeable membrane?
How do substances like CO2 and water move in and out of the cell?
Diffusion is the process by which particles move from a region of higher concentration to a region of lower concentration, until uniform concentration is finally achieved. Carbon dioxide (CO2) moves in and out of the cells by the process of diffusion.
Osmosis is a special type of diffusion. Osmosis is diffusion of water from the region of its higher concentration (pure water or dilute solution) to the region of its lower concentration (strong solution) though a semipermeable membrane. Water moves in and out of the cells by osmosis.
Both diffusion and osmosis are physical or mechanical processes and do not require spending of energy for their performance by the cells.They are both gradient dependent process.
Fill in the gaps in the following table illustrating differences between prokaryotic and eukaryotic cells.
2. Lack of organized nucleus, the genetic material present in the form of nucleoid. Nuclear membrane is absent.
4. Membrane-bound cell organelles such as mitochondria, plastids, Golgi apparatus, lysosomes, etc. are present in the cytoplasm.
Can you name the two organelles we have studied that contain their own genetic material?
Mitochondria and Plastids are two cell organelles that contain their own genetic material. They are also known as Semi-Autonomous organelles as they have their own DNA(Genetic Material) and Ribosomes.
If the organization of a cell is destroyed due to some physical and chemical influence, what will happen?
Cell is the smallest unit of a life which is able to perform all basic functions of life. If the organisation of a cell is destroyed due to some physical and chemical influence, it will not able to perform all living functions like respiration, nutrition, excretion, etc. and the cell will ultimately die.
Why are lysosomes are known as suicide bags?
Where are proteins synthesized inside the cell?
Ribosomes are the sites of protein synthesis. They are small and dense particles which occur freely in the cytosol or remain attached to the endoplasmic reticulum. They take part in the synthesis of proteins.
Make a comparison and write down ways in which plant cells are different from animal cells.
Difference between plant cell and animal cell:
How is a prokaryotic cell different from a eukaryotic cell?
What would happen if the plasma membrane ruptures or break down?
What would happen to the life of a cell if there was no Golgi apparatus?
If there was no Golgi apparatus in the cell, the following cell activities would be affected:
(i) Formation of lysosomes
(iii) The formation of cell plate and cell membrane
(iv) Storage, modification and packaging of products in vesicles
Which organelle is known as the powerhouse of the cell? Why?
Where do the lipids and proteins constituting the cell membrane get synthesized?
The Lipids and Proteins that constitute the cell membrane are mainly synthesized in the Endoplasmic Reticulum.Their are two types of Endoplasmic Reticulum:-
1. Smooth Endoplasmic Reticulum:- Which is without the presence of ribosomes and is specialized for synthesizing lipids used in cell membrane.
2. Rough Endoplasmic Reticulum:- Which has Ribosomes attached on the outer surface and are specialized to synthesize proteins used in cell membrane
How does an Amoeba obtain its food?
Amoeba obtains its food through the process of endocytosis. The plasma membrane of Amoeba is flexible, which help the amoeba to engulf its food particles and other material from its external environment. The flexible plasma membrane that an amoeba uses to capture its prey is known as pseudopodia. (meaning false legs)
What is osmosis?
Osmosis is a special case of diffusion of water molecules from a region of higher concentration to a region of lower concentration through a semi-permeable membrane. The below diagram shows osmosis:-
Carry out the following osmosis experiment:
Take four peeled potato halves and scoop each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup into a trough containing water.
Now
(a) keep cup A empty;
(b) put one teaspoon sugar in cup B;
(c) put one teaspoon salt in cup C.
(d) put one teaspoon sugar in the boiled potato cup D;
Keep these for 2 hours. Then observe the four potato cups and answer the following
(i) Explain why water gathers in the hollowed portion of B and C.
(ii) Why is potato A necessary for this experiment?
(iii) Explain why water does not gather in the hollowed out portions of A and D?
(i) Water gathers in the hollowed portion of unboiled potatoes B and C because the cells of potatoes gained water by endosmosis.
The water moveed inside the cell by osmosis(From higher concentration to Lower Concentration).
(ii) Potato cup A is necessary in the experiment as a ‘control’ for providing comparison with situations created in potato cups B, C and D.