Tag: transport across membrane

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

Choose the best definition for 'diffusion' from the following.

  1. Passive movement from an area of greater concentration to one of lesser concentration

  2. Active movement from an area of greater concentration to one of lesser concentration

  3. Passive movement from an area of lesser concentration to one of greater concentration

  4. Active movement from an area of lesser concentration to one of greater concentration
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Diffusion is a type of passive transport which do not require expenditure of cellular energy for the net movement of a substance from a region of high solute concentration to a region of low solute concentration. This is also referred to as the movement of a substance down a concentration gradient.

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

Different substances move independently depending on their own concentration gradients in?

  1. Simple diffusion

  2. Bulk flow

  3. Osmosis

  4. All the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Diffusion is a passive movement of molecules along their concentration gradient. While osmosis is the diffusion of water molecules through a differentially permeable membrane or semipermeable membrane.


So the correct option is "Simple diffusion". 

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

Diffusion pressure is directly proportional to:

  1. Concentration of molecules diffusing

  2. Kinetic energy of diffusing molecule

  3. Concentration gradient

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The same conditions of temperature and pressure, the molar mass is proportional to the mass density. Therefore, the rate of diffusion of different gases is inversely proportional to the square root of their mass densities.

So, the correct option is 'Concentration of molecules diffusing'.

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

Rate of diffusion of $CO _2$ is $20$ times higher than $O _2$, as it depends upon?

  1. Solubility of gases

  2. Partial pressure

  3. Thickness of membrane

  4. All of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Gas exchange is the process that occurs between oxygen and carbon dioxide. Oxygen is passed from the lungs to the bloodstream and carbon dioxide is eliminated from the bloodstream to the lungs. Exchange of Gas takes place in lungs between the alveoli and capillaries which are tiny blood vessels, placed at the walls of alveoli. The rate of diffusion depends on the thickness of the biological membrane which forms the boundary between the external environment and organisms.

Gas exchange takes place by simple diffusion based on a concentration/pressure gradient. The rate of diffusion depends not only on the solubility of gases but also on the thickness of the membranes involved in gas exchange.
So the correct answer is 'All of these'.

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

Movement of gases across plasma membrane occurs through ______________

  1. Osmosis

  2. Diffusion

  3. Imbibition

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

Diffusion is a process in which the gaseous molecules spreads due to their kinetic energy and movement of molecules from their higher concentration to their lower concentration. Hence, The correct answer is option B.

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

A bottle of perfume is opened in the room opposite to you and within minutes you begin to smell the perfume. This phenomenon is a classic example of

  1. Dialysis

  2. Osmosis

  3. Active transport

  4. Diffusion
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Diffusion is the process of spreading of the gaseous molecule according to their kinetic energy. In this process, particles move from an area of high concentration to an area of low concentration. If the perfume is sprayed in one corner of a room, it will be smelt soon after in the opposite corner. Since the perfume molecules are in constant random motion they bump into each other causing some molecules to be occasionally sent hurtling out of the mass. Gradually, the molecules spread out. 

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

Passive movement of substance from region of high concentration to the region of low concentration

  1. Inhibition

  2. Diffusion

  3. Osmosis

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Diffusion is a passive movement of substances from the region of high concentration to the region of low concentration. Diffusion finally stops when the concentration of particles of two regions becomes the same. Diffusion occurs in both liquids and gases and can take place over long distances. Diffusion in gases is much faster than in liquids the diffusion rate of oxygen in the air is 1,00,000 times more than the diffusion rate of oxygen in the water.

So, the correct answer is B.

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

Diffusion occurs from

  1. Region of higher concentration to lower concentration

  2. Region of lower concentration to higher concentration

  3. Regions of equal concentration

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Diffusion may be defined as the process of movement of gases liquids or solutes from the region of higher concentration to the regions of lower concentration till the molecules are uniformly disturbed throughout the available space. Many substances like gases liquids or solutes can diffuse simultaneously in different directions and at different rates in the same place without interfering with each other.
So, the correct answer is A.