Observe the diagrams of the stomatal apparatus given below and answer the questions that follow:

(a) In which of the diagrams, are the guard cells more turgid?
(b) Mention one function of the stomata other than loss of water vapour during transpiration.
(c) Name the element involved in the opening and closing of stomata.

A stomatal apparatus is shown in the diagram given above. Observe the diagram and answer the following questions.
(a) Identify the cells A and C.
(b) What does B represent in the diagram? How do they aid in the opening of stoma?
(c) What is the immediate cause of opening and closing of stomata?
 

Water moves upward through xylem in plants at a fairly high rate, i.e. about 15 metres per hour. Rani had a doubt whether the water is pushed up or pulled through xylem. Her doubt was cleared by her teacher that it can be by both the methods.
(a) What is the driving force for pushing up water? When does it normally occur?
(b) What is responsible for pulling up of water?
(c) Mention the three properties of water that are responsible for water movement as a column.

Observe the diagram given and answer the questions that follow:

(a) Identify and name the cells A, Band C.
(b) Name the pathway of water movement represented by D.
(c) What does Erepresent and name the substance, it is made of?

(a) Identify the nature of the external solution with reference to that of the cytoplasm of the cell in A, Band C. 
(b) Mention the processes occurring in A and C.
(c) Why is there no net movement of water in B?

In an experimental set up on osmosis, a 'stronger' solution of glucose is taken in a thistle funnel with its mouth tied with a semipermeable membrane. It is kept in a beaker containing a 'weaker' solution of glucose.
(a) What is meant by 'stronger' and 'weaker' solutions?
(b) Which of them has a higher water potential?
(c) Which of them has a lower solute potential?
(d) If a pressure is applied from the upper part of the funnel, the diffusion of water into it stops.
(i) What is this pressure known as?
(ii) Which of the solutions (mentioned above) will have a higher pressure?

Study the figure given below, in which two chambers A and B containing solutions of different concentrations are separated by a selectively permeable membrane.

(a) Solution of which chamber has a lower water potential?
(b) Solution of which chamber has a lower solute potential?
(c) In which direction will osmosis occur?
(d) At equilibrium which chamber will have lower water potential?
(e) If one chamber has a \(\Psi\) of - 2000 kPa, and the other - 1000 kPa, which is the chamber that has the higher \(\Psi\)?
(f) What will be the direction of the movement of water when two solutions with \(\Psi_{\mathbf{w}}\) =-0.2 MPa and \(\Psi_{\mathbf{w}}\) = 0.1 MPa are separated by a selectively permeable membrane?

Certain proteins in the membrane are responsible for facilitated diffusion and active transport; hence, they show some common characteristics. They also differ from each other in certain aspects.
(a) Describe two such similar features of the proteins involved in facilitated diffusion and active transport.
(b) Mention one feature other than the requirement of energy, in which the proteins of active transport differ from that of facilitated diffusion.

Observe the figure given above and answer the following questions.
(a) Identify the process I, II and III.
(b) Why does the transport rate reach a maximum in facilitated diffusion?
(c) What term is given to the membrane proteins involved in active transport?

Transport in plants over long-distance proceeds through the vascular tissues in a process, called translocation. Transport in xylem (of water and minerals) is unidirectional.
(a) How do substances move over short distances?
(b) Organic and mineral nutrients undergo multidirectional transport. Justify (Give four points).