What do A, B, C and D represent in the following figure?
A | B | C | D | |
1. | carrier protein | symport | uniport | antiport |
2. | carrier protein | uniport | antiport | symport |
3. | carrier protein | antiport | symport | uniport |
4. | carrier protein | uniport | symport | antiport |
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Assertion: The concentration of free sugar in the sink is always lower than in the sieve tube.
Reason: The unloaded sugar is consumed during growth or metabolism or converted to insoluble polymers such as starch.
1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.
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Diffusion:
I. does not require any energy expenditure
II. is dependent on a living system
III. is a fast process
IV. is the only means for gaseous movements in plants
1. Only I and IV are correct
2. Only I, II and IV are correct
3. Only I, III and IV are correct
4. Only II and III are correct
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Substances that have a hydrophilic moiety:
1. have to be transported across the plasma membrane by active transport
2. can diffuse across the plasma membrane at a slower rate, if larger in size
3. do not need a concentration gradient to diffuse across the plasma membrane
4. need to be facilitated even along the concentration gradient
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Facilitated diffusion allows cells to:
1. achieve uphill transport without ATP energy
2. select substances for uptake
3. stop transport of hydrophilic substances
4. decrease the rate of diffusion of lipophilic substances
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Unlike a symporter and an antiporter, a uniporter:
1. is not an integral membrane protein
2. is a cell surface carbohydrate
3. is not a co-transporter
4. cannot be used for active transport
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Consider the following statements:
I. | Pure water is usually defined as having a solute potential (Ψπ)of zero. |
II. | A solution will have a lower and hence more negative water potential than that of pure water. |
III. | The more solute molecules present, the more negative the solute potential is. |
Correct statements are:
1. I and II
2. I and III
3. II and III
4. I, II and III
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Consider the following statements regarding water potential:
I. Water potential is the potential energy of water relative to pure free water (e.g., deionized water)
in reference conditions.
II. Typically, pure water at standard temperature and pressure (or other suitable reference condition) is defined as having a water potential of 0.
III. The addition of solutes to water increases its potential (makes it more negative), just as the increase in pressure lowers its potential (makes it more positive).
The correct statements are:
1. I, II and III | 2. I and II |
3. I and III | 4. II and III |
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The pressure that must be applied to a solution to prevent the inward flow of water across a semi permeable membrane is called as:
1. Hydrostatic pressure
2. Water potential
3. Osmotic pressure
4. Osmotic potential
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For imbibition to occur, affinity between the adsorbant and the liquid is:
1. not essential
2. not essential since imbitition is also a diffusion
3. not essential if occurring against the concentration gradient
4. a pre-requisite
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