2.9: Mechanisms of Transport

Question 1

How do ions move across the membrane?

Answer 1

By passive transport (small nonpolar with concentration gradient), facilitated transport (large/polar/ions/small with concentration gradient), active transport (against the concen gradient), or aquaporins(water).

Question 2

Describe the process of passive transport.

Answer 2

Movement of small nonpolar molecules with the concentration gradient across the cell membrane.

Question 3

Describe the process of facilitated diffusion.

Answer 3

Movement of ions, small, or large molecules with the concentration gradient.

Question 4

Describe the process of active transport.

Answer 4

Molecules/ions move against the concentration gradient (ex protein pump)

Question 5

Describe the process of endocytosis.

Answer 5

The cell uses energy to move molecules into the cell. This is done by phagocytosis, receptor mediated, or pinocytosis

Question 6

Describe the process of exocytosis.

Answer 6

Vesicles fuse with the cell membrane in order to release energy and move molecules/ions out of the cell.

Question 7

How are simple diffusion and facilitated diffusion similar?

Answer 7

They both move with the concentration gradient.

Question 8

How are similar diffusion and facilitated diffusion different?

Answer 8

Simple diffusion only allows small nonpolar molecules to pass through, while facilitated diffusion allows all to pass through (including ions).

Question 9

How does water move across cell membrane

Answer 9

Through aquaporins for large amounts or against a concentration gradient, but small amounts can diffuse by themselves.