Chapter 34, Problem 1TYK

Summary Introduction

Introduction:

The transport mechanisms in plants can be long-distance transport and short-distance transport. The long-distance transport is facilitated via vascular tissues throughout the plant body, while short-distance transport moves the substances into and across cells. There are three mechanisms that are responsible for the short-distance transport.

Answer to Problem 1TYK

Correct answer:

Short-distance transport mechanisms in plants move water and dissolved materials by osmosis.

Explanation of Solution

Justification for the correct answer:

Option (a) is “short-distance transport mechanisms include the movement of water and dissolved materials by osmosis.” Osmosis is the mechanism that is responsible for the short-distance transport. Osmosis is a process responsible for the movement of substances across cells due to concentration gradient. Hence, option (a) is the correct answer.

Explanation for incorrect answer:

Option (b) is “short-distance transport mechanisms include bulk flow of solutes and water.” Bulk flow is driven by pressure gradients that occur through the long-distance transport mechanism that uses vascular tissues like xylem and phloem. So, it is an incorrect option.

Option (c) is “short-distance transport mechanisms are not affected by the size of the molecules that have to be transported.” Short-distance transport mechanism is responsible for the movement of substances across the selectively permeable membranes according to concentration gradient. Size of the substance matters because only a certain size can be passed through the membrane pores or transporters. So, it is an incorrect option.

Option (d) is “short-distance transport mechanisms are not affected by the charge of molecules that have to be transported.” Short-distance transport mechanisms are accomplished via osmosis. It is a process that moves the substances across a semipermeable membrane. There are many factors that affect the rate of osmosis, the permeability of membrane being one of them. The permeability of membrane is determined by the charge of the solute. So, it is an incorrect option.

Hence, options (b), (c), and (d) are incorrect.

Conclusion

Therefore, short-distance transport mechanism moves water and other dissolved solutes into and across cells via osmosis.