What causes the opening and closing of guard cells of stomata during transpiration ? Describe point wise.

What is point mutation ? Describe it with example.

Which cell's turgidity causes opening or closing of stomata.

What are closed pipe and open pipe ?

Study the given figure of water movement in the leaf and mark the correct series of pressure gradient that occurs during transpiration. (I) Pressure gradient between the outside air and th air spaces of the leaf. (II) Pressure gradient between photosynthetic cells and on the water filled xylem in the leaf vein.

What causes the potential difference between the two terminals of a cell?

Describe transpiration pull model of water transport in plants. What are the factors influencing transpiration? How is it useful to plants?

An organ pipe of length L open at both ends is found to vibrate in its first harmonic when sounded with a tuning fork of 480 Hz. What should be the length of a pipe closed at one end, so that it also vibrates in its first harmonic with the same tuning fork ?

A player throws a ball upwards with an initial speed of 29.4 ms^(-1) (a) What is the direction of acceleration during the upward motion of the ball ? (b) What are the velocity and acceleration of the ball at the highest point of its motion ? (c) Choose the x = 0 m and t=0 s to be the location and time of the ball at its highest point vertically downward direction to be the positive direction of x-axis and give the signs of position, velocity and acceleration of the ball during its upward and downward motion. (d) To what height does the ball rise and after how long does the ball return to the player's hands ? (Take g = 9.8 ms^(-2) and neglect air resistance).