NEET

Xylem moves its materials

from the leaves to the roots.
from the roots to the leaves.
when the plant is actively photosynthesizing.
if the proper pressure is maintained.

Solution

The tension created by the evaporation of water from leaf surfaces generates a pull on the water column that moves water and nutrients up the xylem from the roots to the leaves.

Primary and secondary active transport both

Generate ATP
Use ATP directly
Can move solutes against their concentration gradient
Include the passive movement of glucose molecule

Aquaporins are

cytoplasmic connections between cortex cells.
openings in the lower epidermis of leaves through which water vapour escapes.
openings into root hairs through which water enters.
water specific channels in membranes that may regulate the rate of osmosis.

Na⁺ / K⁺ pump in a cell is an example of

osmosis
diffusion
passive transport
active transport

Which is incorrect ?

Diffusion is movement of particles from low electro-chemical potential to high electro chemical potential.
Rate of diffusion is directly proportional to concentration.
Rate of diffusion is inversely proportional to distance
Example of diffusion is opening of a bottle of scent in one corner.

Guttation occurs through

lenticels
hydathodes
periderm
stomata

Transpiration rate is measured in an apple plant on both surfaces of leaves. It will be higher on

lower surface
upper surface
None of the two surface
Both (a) and(b)

Solution

Stomata are found only on lower surface.

Which of the following is not true of the carrier molecules involved in facilitated diffusion?

They increase the speed of transport across a membrane.
They concentrate solute molecules on one side of the membrane.
They have specific binding sites for molecules they transport.
They may undergo conformational change upon binding of solutes.

If a plant cell is immersed in water, the water continues to enter the cell until the :

Concentration of the salts is the same inside the cell as outside
Cell bursts
Concentration of water is the same inside the cell as outside
Diffusion pressure deficit is the same inside the cell as outside

Osmosis means

Solute from low concentration to higher concentration
Solute from higher concentration to low concentration
Solvent from low concentration of solution to higher concentration of solution
Solvent from higher concentration of solution to low concentration of solution

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