Q. No.The Casparian strip in plant roots:
1. is located in the walls of the outermost portion of the cortex.
2. is composed predominantly of lignin and hence is impermeable to water.
3. ensures active uptake of all minerals by the roots.
4. ensures that all water and dissolved substances must pass through a cell membrane before entering the vascular cylinder.
1. is located in the walls of the outermost portion of the cortex.
2. is composed predominantly of lignin and hence is impermeable to water.
3. ensures active uptake of all minerals by the roots.
4. ensures that all water and dissolved substances must pass through a cell membrane before entering the vascular cylinder.
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
Translocation in xylem will not be facilitated by:
1. The cohesion of water molecules.
2. A negative water potential.
3. The root parenchyma.
4. The active transport of solutes.
It is a common observation that pine seedlings grown in sterile potting soil grow much slower than seedlings grown in soil from the area where the seeds were collected. The most probable cause for this would be:
| 1. | damage to root hairs during the sterilization process. |
| 2. | the absence of mycorrhizae in the sterilized soil. |
| 3. | lack of essential minerals in a sterilized soil. |
| 4. | non functioning of protein pumps in the sterilized soil. |
Substances travelling via the symplast move from cell-to-cell through:
1. membrane proteins.
2. phospholipid channels.
3. tonoplast.
4. plasmodesmata.
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
Phloem transport differs from xylem transport as:
| 1. | Xylem transport requires active pumping at stomata, transport in phloem is passive. |
| 2. | Phloem movement is solar powered, xylem movement occurs best in dark. |
| 3. | Phloem carries fluid from the soil to the leaves, while xylem is the reverse. |
| 4. | Phloem can reverse direction, depending on the activity of the "source" and "sink" of its materials but the flow in xylem is essentially unidirectional. |
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
Advantages of transpiration to the plants include:
I. evaporative cooling.
II. mineral transport.
III. increased turgor.
1. I and II only
2. I and III only
3. II and III only
4. I, II and III
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
What causes the water to flow into the sieve tube at the source?
1. Diffusion of sucrose into the sieve tube, making it hypertonic.
2. Active transport of sucrose into the sieve tube, making it hypertonic.
3. Active pumping of water by the adjacent companion cell.
4. A lower water potential outside the sieve tube.
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
The apoplast pathway in plants includes all the following except:
1. the lumen of a xylem vessel
2. the lumen of a sieve tube
3. the lumen of tracheids
4. the cell wall of a root hair
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
To unlock all the explanations of 38 chapters you need to be enrolled in MasterClass Course.
Trace the correct path of water from the soil through the plant to the atmosphere:
| 1. | endodermis- cortex - epidermis - vessel elements - intercellular spaces in mesophyll - stomata. |
| 2. | epidermis - cortex - Casparian strip - endodermis - sieve cells - intercellular spaces in the mesophyll - stomata. |
| 3. | Casparian strip - root hairs - epidermis - cortex - xylem - endodermis - intercellular spaces in mesophyll - stomata. |
| 4. | root hairs - cortex - endodermis - vessel elements - intercellular spaces in mesophyll - stomata. |
In classic experiments on the translocation of organic solutes performed by the Italian anatomist Marcello Malpighi in 1686, the bark of a tree was removed in a ring around the trunk. This experiment, called girdling, was also done by T. G. Mason and E. J. Maskell in 1928. The following were the observations:
I. It has no immediate effect on transpiration.
II. Sugars accumulate above the girdle—that is, on the side toward the leaves—and are depleted below the treated region.
What conclusion/s can be drawn from the above observations?
A: Water moves in the xylem, interior to the bark.
B: Sugar is transported in the bark of the tree and that the sieve elements are the cellular channels of sugar transport.
| 1. Only A | 2. Only B |
| 3. Both A and B | 4. Neither A nor B |
© 2024 GoodEd Technologies Pvt. Ltd.