Question 1: Make a comparison to write down ways in which plant cells are different from animal cells.
| Animal Cell | Plant Cell |
|---|---|
| Animal cells are generally small in size. | Plant cells are larger than animal cells. |
| Cell wall is absent. | The plasma membrane of plant cells is surrounded by a rigid cell wall of cellulose. |
| Except the protozoan Euglena, no animal cell possesses plastids. | Plastids are present. |
| Vacuoles in animal cells are many, small, and temporary. | Most mature plant cells have a permanent and large central sap vacuole. |
| Animal cells have a single highly complex and prominent Golgi apparatus. | Plant cells have many simpler units of Golgi apparatus, called dictyosomes. |
| Animal cells have centrosome and centrioles. | Plant cells lack centrosome and centrioles. |
Question 2: How is a prokaryotic cell different from a eukaryotic cell?
| Prokaryotic Cell | Eukaryotic Cell |
|---|---|
| Cell size is generally small (1 – 10 µm). | Cell is generally large (5 – 100 µm). |
| Nuclear region is called nucleoid and is not surrounded by a nuclear membrane. | Nuclear material is surrounded by a nuclear membrane. |
| Only a single chromosome is present. | More than one chromosome is present. |
| Nucleolus is absent. | Nucleolus is present. |
| Membrane-bound cell organelles are absent. | Membrane-bound cell organelles are present. |
| Cell division by fission or budding (no mitosis). | Cell division mitotic or meiotic. |
Question 3: What would happen if the plasma membrane ruptures or breaks down?
Plasma membrane provides a container for the cell organelles and cytoplasm. Moreover, plasma membrane also protects the contents of a cell from external environment. In case the plasma membrane ruptures or breaks down, the cell contents would be exposed to the external environment. This would prove lethal for the cell, and the cell would cease to exist.
Question 4: What would happen to the life of a cell if there is no Golgi apparatus?
Golgi apparatus plays the important role of packaging various substances for further use or for storage. If there was no Golgi apparatus, various substances would not be in a position to be transformed into proper forms for further use. Certain substances, like protein and lipid, are important for the formation of the plasma membrane, and hence, the absence of Golgi apparatus will hamper the formation of new cells during cell division.
Question 5: Which organelle is known as the powerhouse of the cell? Why?
Mitochondria are known as the powerhouse of cells. Mitochondria create energy for the cell, and this process of creating energy for the cell is known as cellular respiration. Most chemical reactions involved in cellular respiration occur in the mitochondria. The energy required for various chemical activities needed for life is released by the mitochondria in the form of ATP (Adenosine triphosphate) molecules. For this reason, mitochondria are known as the powerhouse of cells.
Question 6: Where do the lipids and proteins constituting the cell membrane get synthesized?
Lipids are synthesized in the endoplasmic reticulum. Protein is synthesized in ribosomes which are usually present on the rough ER.
Question 7: How does Amoeba obtain its food?
Amoeba obtains its food through a process called phagocytosis. The cell membrane of amoeba is projected into numerous finger-like outgrowths; called pseudopodia. Amoeba surrounds a food particle by pseudopodia and makes a food vacuole; after engulfing the food.
Question 8: What is osmosis?
The process of movement of a water molecule from a region of higher concentration to a region of lower concentration through a semipermeable membrane is known as osmosis.
Question 10: Which type of cell division is required for growth and repair of the body, and which type is involved in the formation of gametes?
There are two ways in which a cell divides:
- Mitosis
- Meiosis
Mitosis is the type of cell division that is involved in the growth and repair of the body, whereas meiosis is a type of cell division that results in the formation of gametes.