Tag: bio-chemistry

Quizzes (82) Questions (1918)

Questions Related to bio-chemistry

Multiple choice bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

When a grape is placed in concentrated sugar solution, then it will show

  1. Endosmosis

  2. Exosmosis

  3. Imbibition

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When a grape is placed in a solution of concentrated sugar solution, it will show the process of exosmosis and lose water. When a cell is kept in hypertonic solution, it readily crosses the cell wall and fills the space between the cell wall and cell membrane. This hypertonic solution in direct contact with the cell membrane causes plasmolysis and extracts water from the cytoplasm of the cell.

So, the correct answer is option B.

Multiple choice bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

A cell is plasmolysed after being kept in a hypertonic solution. What will be present between the cell wall and plasmalemma?

  1. Isotonic solution

  2. Hypertonic solution

  3. Air

  4. Hypotonic solution
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The cell wall is nonliving and cannot regulate the entry and exit of solute or solvent molecules. When a cell is kept in hypertonic solution, it readily crosses the cell wall and fills the space between the cell wall and cell membrane. This hypertonic solution in direct contact with the cell membrane causes plasmolysis and extracts water from the cytoplasm of the cell.

So, the correct answer is option B.

Multiple choice bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

Which one of the following is the most suitable medium for culture of Drosophila melanogaster ?

  1. Ripe banana

  2. Cow dung

  3. Moist bread

  4. Agar agar
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For the culture of Drosophila melanogaster  one of the most suitable medium is ripe banana, rich in carbohydrates.

So, the correct answer is 'Ripe banana'

Multiple choice bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

OP of a solution can be measured by 

  1. Photometer

  2. Osmometer

  3. Calorimeter

  4. Plasmolysis
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

An osmometer is a device for measuring the osmotic strength of a solution.
Photometer is an instrument for measuring the intensity of light.

A calorimeter is an object used in the process of measuring the heat capacity. 
Plasmolysis is the contraction of the protoplast of a plant cell as a result of loss of water from the cell.
Thus, the correct answer is option (B). 

Multiple choice bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

A higher plant cell covered with cutin and suberin is placed in water. After 15 minutes the cell

  1. Will be killed

  2. Size will increase

  3. Size will remain unchanged

  4. Size will decrease
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Suberin and cutin are complex macromolecules which mainly function as a barrier to movement of water and solutes. Thus if a higher plant cell is covered with cutin and suberin and placed in water then there will not be any change in the size of the cell as cutin and suberin are hard and water repulsive substances. There will not be any exosmosis or endosmosis in such type of cell.

So the correct answer is 'Size will remain unchanged'.

Multiple choice bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

In a plant cell, O.P. is equal to 

  1. T.P. - D.P.D.

  2. D.P.D - T.P.

  3. T.P. - D.P.

  4. D.P.D + T.P.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Here O.P. stands for osmotic pressure, D.P.D. stands for diffusion pressure deficit and T.P. stands for turgor pressure. 

Diffusion pressure deficit( DPD) is the reduction in the diffusion pressure of water in a solution over its pure state due to the presence of solutes and consequent development of turgor pressure. It is equal to the osmotic pressure of the system minus wall pressure:
$D.P.D=O.P.-W.P.(=T.P.)$

Thus the osmotic pressure is the sum of DPD and TP.
So the correct answer is 'D.P.D +T.P'.

Multiple choice bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

Mango dipped in concentrated NaCl solution will

  1. Burst

  2. Contract

  3. Swell

  4. No effect
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A concentrated NaCl solution is hypertonic to the plant cell. Water leaves the cell via osmosis, causing the cytoplasm to shrink away from the cell wall, a process known as plasmolysis.

Multiple choice bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

Movement of water through semipermeable membrane produces 

  1. Wall pressure

  2. Suction pressure

  3. Osmotic pressure

  4. Turgor pressure
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
(A) Wall pressure is the pressure exerted by cell wall against turgor pressure.
(B) Suction pressure is the actual pressure by which cell absorb water.
(C) The movement of water from higher concentration to lower concentration through a semi-permeable membrane is called osmosis. The pressure required to stop osmosis is called osmotic pressure. 
(D) Turgor pressure is pressure applied against the cell wall.
So, the correct answer is 'Osmotic pressure'.