Active Transport Mechanisms and Characteristics

The video tutorial covers different types of transport mechanisms across cell membranes. It begins with carrier mediated transport, highlighting its characteristics such as stereo specificity, competition, and saturation. Facilitated transport is then discussed, emphasizing that it does not require metabolic energy and occurs down an electrochemical gradient. The tutorial proceeds to active transport, explaining that it moves substances against their electrochemical gradient and requires ATP hydrolysis. Primary active transport examples include the sodium-potassium pump and calcium pump. Finally, secondary active transport is explained, with examples of co-transport and counter transport mechanisms.

What is a key characteristic of carrier-mediated transport?

• It does not involve saturation.

• It involves competition for carrier binding sites.

• It is non-specific to the isomer of a substance.

• It requires ATP for all processes.

What happens when all carrier proteins are saturated in facilitated transport?

• Transport stops as no more molecules can be carried.

• Transport continues at an increased rate.

• Transport requires additional energy input.

• Transport reverses direction.

Which of the following is true about facilitated transport?

• It stops when the concentration inside and outside the cell equalizes.

• It requires ATP.

• It occurs against an electrochemical gradient.

• It involves the movement of ions only.

Which of the following is true about active transport?

• It moves substances down their electrochemical gradient.

• It moves substances against their electrochemical gradient.

• It does not require ATP.

• It is the same as facilitated transport.

In primary active transport, what is directly coupled to ATP hydrolysis?

• Movement of glucose into the cell.

• Transport of substances across the cell membrane.

• Diffusion of water molecules.

• Passive transport of ions.

Which pump is an example of primary active transport?

• Proton pump

• Calcium channel

• Sodium-potassium pump

• Sodium-glucose co-transporter

What is the role of ATP in primary active transport?

• It provides energy for moving substances against their gradient.

• It helps in the diffusion of substances.

• It acts as a carrier protein.

• It is not involved in primary active transport.

What is a characteristic of secondary active transport?

• It is directly powered by ATP hydrolysis.

• It does not involve any energy coupling.

• It involves the movement of a single substance.

• It involves the simultaneous movement of two substances.

In co-transport, how do the substances move?

• Both move against their concentration gradients

• In opposite directions

• In the same direction

• One moves while the other stays still

What is an example of counter-transport?

• Sodium and glucose moving in the same direction

• Calcium and sodium moving in opposite directions

• Water and ions moving in the same direction

• Potassium and chloride moving together