Biology: cK-12 - Active Transport

List 3 factors that affect the movement of materials across a membrane. Explain.

1. concentration gradient; 2. Size of the particles that are diffusing; and 3. the temperature of the system affect the rate of diffusion. Some materials diffuse through the membrane, but others require specialized proteins, such as channels and transporters, to carry them out of the cell.

What form of energy is usually used in active transport?

ATP moves molecules from an area of low concentration to an area of high concentration.

How is active transport different from passive transport?

Active transport moves molecules and ions from lower concentration to higher concentration with the help of energy in the form of ATP. On the other hand, passive transport moves molecules and ions from a higher concentration to lower concentration without any energy.

The sodium-potassium pump is an example of an _________________.

active transport pump. It uses ATP to move three sodium ions and two potassium ions to where they are already highly concentrated. Sodium ions move out of the cell; potassium ions move into the cell. As the ions are now able to flow down their concentration gradients, facilitated diffusion returns the ions to their original positions either inside or outside the cell.

During active transportation, molecules flow _____________

against their concentration gradient.

Where does a cell obtain the energy for active transport?

from respiration

During active transport, molecules...

move from an area of low concentration to an area of high concentration. This requires energy called ATP.

What is active transport?

movement of molecules into or out of a cell against a concentration gradient

Active transport and diffusion are ______________.

opposites

Active transport cannot occur without assistance. A ________________ is always required in this process (a protein in the membrane carries the molecules across the membrane

protein carrier

Carrier proteins are often called _________ because they use energy to pump the molecules across the membrane

pumps. Carrier proteins (pumps) move the molecules from a low concentration to a high concentration.

How does the body prevent the loss of sugar in urine?

the kidneys are able to reabsorb all of the filtered glucose from the tubular fluid back into the bloodstream.

Give an example of active transport. Explain what occurs during this process.

the sodium-potassium pump moves sodium ions to the outside of the cell and potassium ions to the inside of the cell.