Carry out the following osmosis experiment:
Take four peeled potato halves and scoos each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup in 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 two 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 B and C in light of the fact that in both the circumstances there is contrast in the centralization of water in the box and water in some Potato. Therefore, osmosis happens as the potato cells go about as a semipermeable membrane.
(ii) Potato A is necessary for this experiment for comparison, it acts as a control.
(iii) Water doesn't gather in the emptied out parts of A and D. As some A doesn't have change in the concentration for water to stream. For osmosis to happen one of the concentrations ought to be higher than the other.
In cup D, the cells are dead and thus the semi-permeable membrane doesn't exist for the progression of water and no osmosis happens.
How does an Amoeba obtain its food?
Why is the cell called the structural and functional unit of life?
Fill in the gaps in the following table illustrating differences between prokaryotic and eukaryotic cells.
Prokaryotic Cell | Eukaryotic Cell |
1. Size : generally small (1-10 μm) 1 μm = 10-6 m |
1. Size generally large (5-100 μm) |
2. Nuclear region: ________________ and known as _________________ |
2. Nuclear region: well defined andsurrounded by a nuclear membrane |
3. Chromosome: single |
3. More than one chromosome |
4. Membrane-bound cell organelles absent | 4. _______________________ _______________________ |
Why are lysosomes known as suicide bags?
Where do the lipids and proteins constituting the cell membrane get synthesised?
How is a prokaryotic cell different from a eukaryotic cell?
How do substances like CO2 and water move in and out of the cell? Discuss.
Make a comparison and write down ways in which plant cells are different from animal cells.
Who discovered cells, and how?
What is osmosis?
Which of the following has more inertia: (a) a rubber ball and a stone of the same size? (b) a bicycle and a train? (c) a five-rupees coin and a one-rupee coin?
State the universal law of gravitation.
Which of the following are matter?
Chair, air, love, smell, hate, almonds, thought, cold, cold-drink, smell of perfume.
A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force (Fig. 11.3). Let us take it that the force acts on the object through the displacement. What is the work done in this case?
What is meant by a pure substance?
How does the sound produced by a vibrating object in a medium reach your ear?
In a reaction, 5.3 g of sodium carbonate reacted with 6 g of ethanoic acid. The products were 2.2 g of carbon dioxide, 0.9 g water and 8.2 g of sodium observations are in agreement with the law of conservation of mass.
sodium carbonate + ethanoic acid → sodium ethanoate + carbon dioxide + water
What are canal rays?
State any two conditions essential for good health.
How is our atmosphere different from the atmospheres on Venus and Mars?
When will you say a body is in
(i) uniform acceleration? (ii) non-uniform acceleration?
How is soil formed?
What do you mean by acceleration due to gravity?
In which of the following case do you think the long-term effects on your health are likely to be most unpleasant?
• if you get jaundice,
• if you get lice,
• if you get acne.
Why?
What are the differences between the mass of an object and its weight?
A stone is thrown vertically upward with an initial velocity of 40 m/s. Taking g = 10 m/s2, find the maximum height reached by the stone. What is the net displacement and the total distance covered by the stone?
How are the criteria for deciding divisions in plants different from the criteria for deciding the subgroups among animals?
To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water at 293 K. Find its concentration at this temperature.
A driver of a car travelling at 52 km h-1 applies the brakes and accelerates uniformly in the opposite direction. The car stops in 5 s. Another driver going at 3 km h-1 in another car applies his brakes slowly and stops in 10 s. On the same graph paper, plot the speed versus time graphs for the two cars. Which of the two cars travelled farther after the brakes were applied?
What can you say about the motion of an object whose distance-time graph is a straight line parallel to the time axis?