Active Transport

Question 1

what is the definition of active transport?

Answer 1

-the movement of molecules or ions into or out of a cell from a region of lower concentration to a region of higher concentration using ATP and carrier proteins

Question 2

what does ATP do during active transport?

Answer 2

-directly moves individual molecules using a concentration gradient which has already been set up by active transport (co transport)

Question 3

how is active transport different from passive transport?

Answer 3

• metabolic energy in the form of ATP is needed

- substances are moved against a concentration gradient from a lower to a higher concentration

Question 4

how does active transport of a single molecule or ion occur?

Answer 4

• the carrier proteins span the plasma membrane and the molecule or ion binds to its receptor sites to be transported on one side of the membrane
• on the inside of the cell/organelle ATP binds to the molecule causing it to split into ADP and a phosphate molecule causing the protein molecule to change shape and open the opposite side of the membrane to release the molecule there
• the phosphate molecule is released from the protein which causes the protein to revert to its original shape ready for the process to be repeated
• the phosphate molecule then recombines with the ADP to form ATP during respiration

Question 5

what are the similarities and differences between active transport and facilitated diffusion?

Answer 5

• both use carrier proteins
• facilitated diffusion occurs down a concentration gradient while active transport occurs against a concentration gradient
• facilitated diffusion does not require metabolic energy while active transport does

Question 6

what is the sodium potassium pump?

Answer 6

• more than one molecule or ion may be moved in the same direction at the same time by active transport
• occasional the molecule or ion is moved into a cell/organelle at the same time as a different one is being removed from it
• sodium ions are actively removed from the cell/organelle while potassium ion are actively taken in from the surroundings
• this process is essential to a number of important processes in the organism including the creation of a nerve impulse