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Question 22. Name two cells with cell wall.
Answer: Onion cell (plant cell) and fungi.
Question 23. Why does mitochondria have largely folded inner membrane?
Answer: Mitochondria is the site for cellular respiration and provides energy to the cell. The largely folded inner membrane provides the increased surface area for ATP-generating chemical reactions.
Question 24. Which organelle makes the digestive enzyme of lysosome?
Answer: Rough endoplasmic reticulum makes the digestive enzyme of lysosomes.
Question 25. What are cisterns?
Answer: The golgi bodies consist Of a system of membrane-bound vesicles arranged in stacks called cisterns.
NCERT Solutions For Class 9 Science Chapter 5 Short Answer Type Questions
Question 1. State two conditions required for osmosis.
Answer: (i) The difference in the concentration of water, one should have higher concentration than the other.
(ii) Semi-permeable membrane is also required through which water will flow.
Question 2. What is plasmolysis?
Answer: When a living plant cell loses water through osmosis there is shrinkage or contraction of the contents of the cell away from the cell wall. This phenomenon is known as plasmolysis.
Question 3. How does fungi and bacteria can withstand much greater changes in the surrounding medium than animal cells?
Answer: The cell wall present in fungi and bacteria permits these cells to withstand very dilute external medium without bursting.
The cells take up water by osmosis, swells, and builds the pressure against the cell wall. The wall exerts an equal pressure against the swollen cell. It is because of the cell wall, such cells can withstand much greater changes in the surrounding medium than animal cells.
Question 4. Give the function of nuclear membrane.
Answer: The nuclear membrane present as outer covering in the nucleus allows the transfer of material inside and out of the nucleus to cytoplasm.
Question 5. Name the cell-organelles that have their own DNA and ribosomes.
Answer: The cell organelles with their own DNA and ribosomes are mitochondria and plastids.
Question 6. State the difference between smooth endoplasmic reticulum and rough endoplasmic reticulum.
Answer:
NCERT Solutions For Class 9 Science Chapter 5 The Fundamental Unit of Life SAQ Q6
Question 7. What is endocytosis?
Answer: The cell membranes flexibility allows the cell engulf in food and other material from its external environment. This process is known as endocytosis. E.g., Amoeba acquires its food through such processes.
Question 8. What is the function of vacuoles?
Answer: Vacuoles are storage sacs for solid or liquid content. In plant cells it provides turgidity and rigidity to the cell. In single-celled organisms vacuoles store food, e.g., Amoeba.
Question 9. When we put raisins in water, why do they swell?
Answer: Raisins are dry with less water inside, when they are kept in water, osmosis takes place, water flows through the cell wall, cell membrane of the raisins and therefore it swells.
Question 10. Why are lysosomes called suicidal bags?
Answer: Lysosomes contain digestive enzymes in it and helps in the cleaning of cell by digesting any foreign materials entering the cell, such as bacteria, food and old cell organelles.
When the lysosomes burst, the digestive enzyme digest its own cell. Hence it is called as suicidal bag.