Tag: bio-chemistry

Questions Related to bio-chemistry

The given table shows properties of four cells systems A, B, C and D. The maximum rate of inward diffusion of water will be observed in which of these systems?

System Intracellular concentration of water Extracellular concentration of water
A $0.09$M $0.11$M
B $0.2$M $0.5$M
C $0.05$M $0.7$M
D $0.03$M $0.6$M
bio-chemistry absorption by roots - the processes involved diffusion transport across membrane means of transport

  1. System A

  2. System B

  3. System C

  4. System D

Show answer
Correct Option: C
Explanation:
Diffusion of water will occur from higher concentration to lower concentration. Maximum rate of inward diffusion of water will occur where concentration difference is maximum. System C has maximum concentration difference of 0.65M. Hence, maximum diffusion will occur in system C.

So, the correct answer is 'System C'.

Movement of the molecules of solids, gases or liquids from the region of their higher concentration to the region of their lower concentration is known as ___________.

bio-chemistry absorption by roots - the processes involved diffusion transport across membrane means of transport

  1. Diffusion

  2. Osmosis

  3. Imbibition

  4. Active transport

Show answer
Correct Option: A
Explanation:

Diffusion is the movement of the particles of different substances from the region of their higher concentration, free energy or diffusion pressure to the region of their lower concentration, free energy or diffusion pressure.

Water in adjacent xylem moves into the phloem by process of :

bio-chemistry absorption by roots - the processes involved diffusion transport across membrane means of transport

  1. Simple diffusion

  2. Active transport

  3. Osmosis

  4. Facilitated diffusion

Show answer
Correct Option: C
Explanation:

Water is passively transported into the roots and then into the xylem. The forces of cohesion and adhesion cause the water molecules to form a column in the xylem. Water moves from the xylem into the mesophyll cells, evaporates from their surfaces and leaves by diffusion through the stomata. The increased solute concentration causes water to move by osmosis from the xylem into the phloem. The positive pressure that is produced pushes water and solutes down the pressure gradient. So, the correct answer is "Osmosis".

In photosynthesis, oxygen is given out by the process of

bio-chemistry absorption by roots - the processes involved diffusion transport across membrane means of transport

  1. Diffusion 

  2. Osmosis

  3. Transpiration

  4. None of the above

Show answer
Correct Option: A
Explanation:

Diffusion is a process in which the molecules intermingle due to their kinetic energy and movement of molecules is from higher concentration to lower concentration. During photosynthesis, the plant produces oxygen as a byproduct and hence the concentration of oxygen inside the cell is higher than the outer environment. Plant releases oxygen in external environment through diffusion process.

Aquatic plants lose most of their metabolic wastes by .......... process.

bio-chemistry absorption by roots - the processes involved diffusion transport across membrane means of transport

  1. Diffusion

  2. Osmosis

  3. Reverse osmosis

  4. Dialysis

Show answer
Correct Option: A
Explanation:

Aquatic plants lose most of their metabolic wastes by diffusion directly into the water, surrounding them as the concentration of that metabolic wastes is more in the cell as compared to the surroundings. They do not have to store the waste products as terrestrial plants do. Thus, the correct answer is option A.

Name the process which is useful for the movement of substances like CO$ _2$ and O$ _2$ across the cell membrane.

bio-chemistry absorption by roots - the processes involved diffusion transport across membrane means of transport

  1. Diffusion

  2. Osmosis

  3. Active diffusion

  4. Reverse osmosis

Show answer
Correct Option: A
Explanation:

CO$ _2$ and O$ _2$ are gases so, they move in and out of the cell by diffusion. Diffusion is a process in which the gaseous molecules spreads, due to their kinetic energy and movement of molecules is from higher concentration to lower concentration. 

Which is incorrect ?

bio-chemistry absorption by roots - the processes involved diffusion transport across membrane means of transport

  1. Rate of diffusion is directly proportional to concentration.

  2. Rate of diffusion is inversely proportional to concentration.

  3. Diffusion is movement of particles from low to high electrochemical potential.

  4. Example of diffusion is opening of scent or ammonia in one corner.

Show answer
Correct Option: C
Explanation:

Diffusion is the movement of water molecules from higher concentration to lower concentration. It also transfers the molecule along the electrochemical potential gradient.

So, the correct answer is 'Diffusion is the movement of particles from low to high electrochemical potential.'

The given table shows properties of four cells systems A, B, C and D. The maximum rate of inward diffusion of water will be observed in which of these systems?

System Intracellular concentration of water  Extracellularconcentration of water
A 0.09 M 0.11 M
B 0.2 M 0.5 M
C 0.05 M 0.6 M
D 0.03 M 0.7 M
bio-chemistry absorption by roots - the processes involved diffusion transport across membrane means of transport

  1. System A

  2. System B

  3. System C

  4. System D

Show answer
Correct Option: C
Explanation:

A.In the system A, inward diffusion of water takes place with slow rate

B. In the system B, inward diffusion of water takes place with medium rate.

C.In the system C, inward diffusion of water takes place with maximum rate

D.In the system D, inward diffusion of water takes place with high rate

So, the correct option is ‘System C’.

The factor which does not affect the rate of alveolar diffusion is

bio-chemistry absorption by roots - the processes involved diffusion transport across membrane means of transport

  1. solubility of gases

  2. thickness of the membranes

  3. pressure gradient

  4. reactivity of the gases.

Show answer
Correct Option: D
Explanation:

$O _{2}$ and $CO _{2}$ are exchanged in the alveoli by simple diffusion. The factors that affect the diffusion are pressure gradient of the gases, solubility of the gases and the thickness of the membranes involved in diffusion.