D. Higher order Thinking Skills.
1. A person with swollen gums rinses his mouth with lukewarm salt water and swelling
of his gums decreases. This is because
a. The gums absorb the salt water solution.
b. The salt water solution lowers the temperature of the water in the gums.
c. The salt in the solution moves against the concentration gradient.
d. The water in the gums moves out due to high concentration of salt in the solution.
2. Ritika observed onion peel cells in the lab and could view the cell wall, cytoplasm
and nucleus clearly. Suddenly her friend spilled a few drops of salty water on the slide
having onion peel cells.She observes some changes in the cells after sometime
a. What changes would have been observed by Ritika?
b. Name the process that caused the changes in the cells.
c. Would there be similar changes observed ,if she had prepared a slide of cheek
cells?
3. Look at the diagram carefully
a. Which part of the above diagram can carry the ‘hereditary material’?
b. Who discovered the nucleus for the first time?
c. Why is it called the ‘ control centre’ of the cell ?
4. If you are provided with some vegetables to cook, you generally add salt into the
vegetables during the cooking process.
a. What happens to the vegetables after adding salt ?
b. Which mechanism is responsible for the changes?Explain.
5. Why does the skin of your mother’s fingers shrink when she washes clothes for a long
time?
a. What is responsible for these changes?
b. Explain the process in brief.
Q 3 )
Answers
1) d
3) a) chromatin
b) Robert Brown
c) because it controls the activity of the cell and helps to carry the hereditary material
4) a) the vegetables starts losing water
b) osmosis
Nice to meet you BTS army hope my answer is not wrong and will help you
Answer:
1. A person with swollen gums rinses his mouth with lukewarm salt water and swelling of his gums decreases. This is because d. The water in the gums moves out due to high concentration of salt in the solution.
2. a) The onion cells started to shrink. Onion peel when placed in salt solution, shrinks as water cells cytoplasm moves out of the cell i.e., hypertonic solution.
b) As salt water is hypertonic solution, exosmosis (movement of water out of the cell) will take place in the cells, causing cell membrane to shrink away from the cell wall. This is called plasmolysis.
c) No, it happens only in plant cells.
3. a) Nucleolus carry the hereditary materials. RNA and DNA are the hereditary materials, which are present in the nucleus.
b) Robert Brown in 1831 in the plant cells.
c) The nucleus acts as the cell's brain by telling it what to do, how to grow, and when to reproduce. The nucleus is home to the cell's genes.So, it is called the 'control centre ' of the cell.
4. a) After adding salt, vegetables release water.The addition of salt makes the external environment hypertonic. This means that the concentration of water outside is lowered as compared to the concentration of water inside the cell.
b) The mechanism is called Osmosis.
5. a) Soap solution is hypertonic in nature which makes the water move out of the cells in hand, which results in shrinkage of fingers when you wash clothes for a long time.That is ex-osmosis takes place.
b) Exosmosis is the movement of water outside the cells when a cell is placed in a hypertonic solution. The cell becomes flaccid by the movement of water outside.
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