Question

How do substances like carbon dioxide $(C{O_2})$ and water $({H_2}O)$ move in and out of the cell?
A) Diffusion and osmosis
B) Reverse osmosis and diffusion
C) Facilitated diffusion and diffusion
D) None of these

Answer 1

Carbon dioxide are major elements for human beings to live on this planet as oxygen is inhaled by means of humans and animals and carbon dioxide is exhaled. The plants take in carbon dioxide and give out oxygen by the process of photosynthesis. So these two gasses are important in our life.

Complete answer:
Across mobile membranes carbon dioxide pass or transport by way of simple diffusion, and no energy input is required in this process, and on either side of the membrane, it is driven by means of differences in concentration. So, carbon dioxide moves through diffusion.

In case of water, it moves according to the concentration gradient that is from a region of higher concentration to lower across a semipermeable membrane. This is known as osmosis.
Reverse osmosis- It is the movement of ions across the membrane against the concentration gradient. This phenomenon is applied for purifying water.
Facilitated diffusion- It is the passive transport of molecules across a membrane. This movement can also be against the concentration gradient. It requires energy in the form of ATP.

Thus the correct answer is option ‘A’.

Note: A real-life instance of diffusion can be the spreading of an air freshener through a room or to provide coloration to the glass of water few drops of dyes are sufficient as in this molecule's journey from higher to decreased concentration. Osmosis can be explained by the phenomenon of swelling of resins when placed in a hypotonic solution (Concentration of water is greater than solvent).