FREE NEET Biology Practice MCQ Test: Transport In Plants Exercise 1 Questions Answers With Detailed Explanations [PDF]

Answer: (a)

Answer: (c)

There is evidence to believe that besides organic acids the turgidity of guard cells is usually controlled by $K^{+}$ , $Cl^{-}$ and $H^{+}$ . The opening of stomata is initiated by exertion of $H^{+}$ by guard cells, intake if $K^{+}$ and $Cl^{-}$ , disappearance of starch and appearance of organic acids like malic acid.

Answer: (c)

Answer: (d)

Answer: (b)

Materials capable of imbibition such as proteins and cellulose in living beings cause seeds to swell when they are placed in water.

Answer: (b)

Answer: (c)

Answer: (a)

The opening and closing of stomata depends on the concentration of solutes in the guard cells (the main component of the solute concentration in guard cells is $K^{+}$). When the concentration of solutes, $K^{+}$ ion guard cells increases, their osmotic pressure increases. In other words, their water potential decreases. As a result of this, they absorb water from their surrounding epidermal cells, and their turgidity increases.

Answer: (a)

Diffusion pressure deficit is the reduction in the diffusion pressure of water in a system over its pure state. It is given by DPD = O.P – W.P (T.P). DPD determines the direction of net movement of water. It is always from an area or cell of lower DPD to the area or cell of higher DPD. So, cell A having lower DPD, water will move from cell A to B.

Answer: (c)

Answer: (b)

Answer: (d)

Answer: (c)

An example of imbibition is swelling of seed in soil. Imbibition is a type of diffusion process along the concentration gradient, that allows the solid to absorb water and increase in volume. When seed is put in the soil it absorbs water which activates enzymes present in the seed and this induces seed germination.

Uptake of water by root hair is an example of absorption, exchange in of gases through stomata is an example of diffusion and opening of stomata is an example of turgor pressure.

Answer: (a)

The entry of water in cell develops turgor pressure, which exerts pressure on the cell wall. Cell wall counteracts the turgor pressure. As the turgor pressure increases, wall pressure also increases to prevent the cell from bursting.

Answer: (b)

Answer: (a)

Answer: (b)

Answer: (c)

Answer: (b)

Guard cells help in transpiration. Transpiration is the evaporation of water from the aerial parts of plants, especially leaves but also stems, flowers and roots. Stomatal opening allowing the diffusion of carbon dioxide and oxygen during photosynthesis.

Answer: (d)

Transpiration pull cohesion theory for ascent of sap in trees is most widely accepted. This concept was proposed by Dixon and Jolly, 1884. It is based up on three basic assumptions which are cohesion in between water molecules, continuity of water column and transpiration pull.