Tag: means of transport

Questions Related to means of transport

The movement of free atoms from higher concentration to lower concentration is called:

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

  1. Osmosis

  2. Diffusion

  3. Endosmosis

  4. Exosmosis

Show answer
Correct Option: B
Explanation:

Osmosis is the movement of solvent through a semi-permeable membrane to a region of higher solute concentration.

Diffusion is a process of movement of ions or molecules from a higher concentration to an area of lower concentration.
Endosmosis is the process of movement of solvent from outside to the inside of the cell.
While, exosmosis is the process of movement of solvent from inside to the outside of the cell.
Thus, the correct answer is option (B). 


State whether the following statements are true or false.
Lipid-soluble molecules are able to diffuse into a cell more rapidly than water-soluble molecules.

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

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Fat-soluble molecules, such as steroids, alcohols, and some vitamins, can dissolve in the lipid portion of the membrane and diffuse in and out the cell. Water soluble molecules can't pass through the hydrophobic portion of the phospholipid layer.

So, the correct option is 'True'.

Which one of the following process of transporting substances across a membrane does not involve a change in the shape of the transport protein?

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

  1. Active transport

  2. $Na^+ - K^+$ pump

  3. Simple diffusion

  4. Facilitated diffusion

Show answer
Correct Option: C
Explanation:

Both active transport and facilitated diffusion are mediated through membrane proteins, here channel proteins allow diffusion of solutes of appropriate size only, so in this size and shape of transport protein changes while simple diffusion does not require proteins for transportation.

 So, the correct option is 'Simple diffusion'.

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.'