Class 9 Science - Chapter The Fundamental Unit of Life NCERT Solutions | Which organelle is known as the powerhou

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.

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.

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?

Make a comparison and write down ways in which plant cells are different from animal cells.

Who discovered cells, and how?

How do substances like CO2 and water move in and out of the cell? Discuss.

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?

What are the two forms of oxygen found in the atmosphere?

Which method is commonly used for improving cattle breeds and why?

How much momentum will a dumb-bell of mass 10 kg transfer to the floor if it falls from a height of 80 cm? Take its downward acceleration to be 10 m s^-2.

Identify the solutions among the following mixtures.

(a) Soil
(b) Sea water
(c) Air
(d) Coal
(e) Soda water.

What are the advantages of classifying organisms?

What is soil erosion?

Calculate the work required to be done to stop a car of 1500 kg moving at a velocity of 60 km/h?

What are macro-nutrients and why are they called macro-nutrients?

On the basis of Thomson’s model of an atom, explain how the atom is neutral as a whole.

How are clouds formed?