Question

QUESTION 32 Which of the following is an example of a gradient-driven active transporter O A Aquaporin water transport B. Na+K+ ATPase glucose permease transport D. Osmosis E. Na glucose symport F. All of these answers are correct G. None of these answers are correct

Answer 1

32. An example of a gradient- driven active transporter is- (E.) Na⁺ glucose symport

• Active transport is a process in which molecules move across the cell membrane from a region of lower concentration to a region of higher concentration, i.e the molecules are transported against the concentration gradient. Active transport can be primary or secondary.
• In primary active transport, it is done by utilizing energy from ATP hydrolysis.
• In secondary active transport, it is done by using an electrochemical gradient of other solute. So, in this one solute is moving down the concentration gradient (from a region of its higher concentration to a region of lower concentration and this drives the uphill movement ( from a region of lower concentration to a region of higher concentration)of other molecule such as monosaccharide or amino acids. So, it can also be called as gradient- driven active transport. This transport can be either symport (co- transport of two molecules in the same direction)or antiport (co- transport of two molecules in the opposite direction).
• From the options, Na⁺ glucose symport is an example of a gradient- driven active transporter.
• In Na⁺ glucose symport, transport of organic solute glucose against its concentration gradient is driven by concomittant transport of sodium ions down their electrochemical gradient. Both the solutes move in the same direction.

About the other options-

• Aquaporin water transport is an example of Facilitated Diffusion
• Na+K+ATPase is an example of primary or direct active transport.
• Glucose permease transport is an example of Facilitated Diffusion
• Osmosis is a kind of simple diffusion