Tag: absorption by roots - the processes involved

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Questions Related to absorption by roots - the processes involved

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

Diffusion is more rapid in liquid than in gases.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Diffusion is more rapid in gas as compared to liquid, this is because gases have more kinetic energy and gas molecules are smaller compared to liquid molecules. When the temperature is raised, this results in the increase of kinetic energy of the molecules and rate of diffusion is also increased.

So, the correct answer is option B.

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

Plasma membrane does not have carrier molecules for

  1. Active transport

  2. Simple diffusion

  3. Faciliated diffusion
  4. $Na^+-K^+$ pump
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In facilitated diffusion, molecules diffuse across the plasma membrane with assistance from membrane proteins, such as channels and carriers.
For active transport, as the movement is against the concentration gradient, carriers or pumps are required. Similarly with Na-K pump.
Simple diffusion is just the movement of molecules from a place of higher concentration to lower concentration without any carrier molecules.
Thus, the correct answer is option (B). 

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

Cell wall shows

  1. Semi permeability

  2. Selective permeability

  3. Complete permeability

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

Cell wall is the outer protective layer of a cell. Cellulose is an important constituent of the cell wall. It is made up of carbon, hydrogen and oxygen. It is is selectively permeable, as it allows molecules upto 30-60kD to pass easily without the expenditure of energy and fully permeable to water and proteins molecules.

Differential permeability is a semipermeable membrane which is almost completely impermeable to solute molecules, but is permeable to the solvent.
Complete permeability is a membrane which is almost completely permeable to all the solute and solvent molecules.
Semipermeable membrane allows certain molecules or ions to pass through it by diffusion
So, the correct answer is option ' Selectively permeable'.

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

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

  1. Osmosis

  2. Diffusion

  3. Endosmosis

  4. Exosmosis
Reveal answer Fill a bubble to check yourself
B Correct answer
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). 


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

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.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
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'.

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

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

  1. Active transport
  2. $Na^+ - K^+$ pump

  3. Simple diffusion

  4. Facilitated diffusion
Reveal answer Fill a bubble to check yourself
C Correct answer
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'.

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

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

  1. System A

  2. System B

  3. System C

  4. System D
Reveal answer Fill a bubble to check yourself
C Correct answer
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'.
Multiple choice bio-chemistry absorption by roots - the processes involved diffusion transport across membrane means of transport

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 ___________.

  1. Diffusion

  2. Osmosis

  3. Imbibition

  4. Active transport
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

  1. Simple diffusion

  2. Active transport

  3. Osmosis

  4. Facilitated diffusion
Reveal answer Fill a bubble to check yourself
C Correct answer
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".

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

In photosynthesis, oxygen is given out by the process of

  1. Diffusion

  2. Osmosis

  3. Transpiration

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