Question

Answer the mcqs
1) When a cell is placed 0.5 M concentrated solution of sugar, there is no change in its volume. but of the same cell is placed in 0.5 M concentrated solution of NaCl there will be
a) decrease in volume b) increase in volume c) no change d) none of the above.
2) Inhibition involves a) diffusion of water b) movement of water into imbibant through capillary c) movement of water into imbibant through diffusion as well as capillary action d) adsorption of water.
3) Cell A with op = 10 atm and tp = 5 atm is in contact with cell B having op = 15 atm and tp = 12 atm. the flow of water will be a) from a to b b) equal flow c) from b to a d) no flow.
4) no. of stomata present per cm3 of a common leaf is about a) less than 100 b) more than 100000 c) 1 million d) 10000
5) at constant temp. the rate of transp. will be higher at a) sea level b) 1 km below sea level c) 1 km above sea level d) 1.5 km above sea level
6) during absorption of water by roots the water potential of cells sap is lower that of a) pure water and soil solution b) neither pure water nor soil solution c) pure water but higher than that of soil solution d) soil solution but higher than that of pure water solution.

plzzzzzzz it is my homework and I have not got answer of these. help.

Answer 1

1) c) No change in volume
= This is due to the phenomenon of ionisation, where the solution of the electrolytes have more solute particles as compared to a nonelectrolyte of the same strength.

2) c) Movement of water into imbibant through capillarity.
= An imbibant is made up of a number of particles separated by fine interstices. During imbibition water passes or seeps into the interstices as well as is adsorbed over the particles. The process occurs through diffusion (from the outside) and capillarity (into the inside of the imbibant).

3) c) from "B" to "A"
= In A, D.P.D. = 5 atmospheric pressure while in B it is 3 atmospheric pressure. The flow of water is lower from lower D.P.D. to higher D.P.D. across a semipermeable membrane.

4) d) 10000
= For common crop plants the number of stomata is about ten thousand per cm^2 area of leaf.

5) d) 1.5 km above sea level
= Height above sea level indicates that there is lower atmospheric pressure and increases the evaporation.

6) a) Pure water and soil solution
= The water potential has a negative value where lower value will only mean negative.