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Q1: Why is the cell called the structural and functional unit of life?
Ans: The cell is called the structural and functional unit of life because it provides shape (structure) to the organisms. It also contains cell organelles that performs all the function which are necessary for the life such as respiration, digestion, food intake, protein manufacturing etc.
Q2: How do substances like CO2 and water move inside and outside the cell? Discuss.
Ans: Both CO2 and water move from higher concentration to lower concentration through the plasma membrane. The process by which CO2 moves inside and outside is called diffusion. The process by which water moves inside and outside the cell is called osmosis.
Q3: Why is plasma membrane called the selectively permeable membrane?
Ans: The plasma membrane is called the selectively permeable membrane because it allows only a few substances such as CO2 and water to move inside and outside the cell.
Q4: Can you name the two organelles we have studied that contain their own genetic material?
Ans: Mitochondria and Plastids are the two organelles that have their own genetic material.
Q5: Why are lysosomes known as suicide bags?
Ans: The lysosomes contain the powerful digestive enzymes. In case, the cell is damaged and the lysosomes are burst, its enzyme may digest the cell itself. That is why lysosomes are called suicide bags.
Q6: Where are the proteins synthesised inside the cell?
Ans: The proteins are synthesized in ribosomes inside the cell.
Q1: Make a comparison and write down ways in which the plant cells are different from animal cells.
Ans:
|
Plant Cell |
Animal Cell |
|
The plastid is present |
Plastid is absent |
|
There is one big vacuole |
A number of small vacuoles are present |
|
Cell wall is present |
Cell wall is absent |
|
It has rigid shape |
It has irregular shape |
Q2: What would happen if the plasma membrane ruptures or break down?
Ans: Plasma membrane is the outer covering of the cell, which allows some substances to go inside and outside the cell. If it ruptures or break downs these functions won’t be carried out and the cell will die slowly.
Q3: What would happen to the life of a cell if there was no Golgi apparatus?
Ans: The main function of Golgi apparatus is to transport the protein synthesized in ER to other organelles and outside the cell. Without Golgi apparatus, the life of cell is not possible because no growth will tend to happen.
Q4: Which cell organelle is known as the powerhouse of the cell? Why?
Ans: Mitochondria is known as the powerhouse of the cell because it provides the required energy to the cell in the form of ATP which stands for Adenosine triphospate. This energy is required by the cell for various chemical activities.
Q5: Where do the lipids and proteins constituting the cell membrane get synthesized?
Ans: The lipids and proteins constituting the cell membrane get synthesized in Smooth endoplasmic reticulum (SER).
Q6: How dose Amoeba obtain its food?
Ans: Plasma membrane in cell like amoeba allows food to enter inside the body by the process known as endocytosis.
Q7: What is osmosis?
Ans: The process by which the water is exchanged from the cell is called osmosis. In osmosis, the water move from higher concentration to lower concentration.
Q8: Which type of cell division is required for growth and repair of body and which type is involved in formation of gametes?
Ans: Mitosis cell division process is required for growth and repair of body, in which two new cells are formed which are identical to parent cell.
In meiosis division, process the cells of reproductive organs form gametes. After, division, four new cells are formed with half the number of chromosomes present inside them.