Biological Membranes (CH8)

Question 1

The most basic of all membrane traffic processes, in which substrates move down their concentration gradient directly across the membrane. Only particles that are freely permeable to the membrane can undergo this.

Answer 1

Simple Diffusion

Question 2

Is a specific kind of simple diffusion that concerns the movement of water. Water will move from a region of lower solute concentration to one of higher solute concentration.

Answer 2

Osmosis

Question 3

If the concentration of solutes inside the cell is higher than the surrounding solution, then the solution is said to be?

Answer 3

Hypotonic

Question 4

If the concentration of solutes inside the cell is lower than the surrounding solution, then the solution is said to be?

Answer 4

Hypertonic

Question 5

If the solutions inside and outside the cell are equimolar, they are said to be?

Answer 5

Isotonic

Question 6

Osmotic pressure is best thought of as a “sucking” pressure, drawing water into the cell in proportion to the concentration of the solution. What is the equation for measuring this?

Answer 6

π = iMRT

• i = van’t Hoff factor (which is the number of particles obtained from the molecule in solution)
• M = Molarity
• R = ideal gas constant
• T = temperature in kelvins

Question 7

Simple diffusion for molecules that are impermeable to the membrane (large, polar, or charged); the energy barrier is too high for these molecules to cross freely. Uses carriers or channels for transport.

Answer 7

Facilitated Diffusion

Question 8

Transport that requires energy but this source of energy can vary.

Answer 8

Active Transport

Question 9

Uses ATP or another energy molecule to directly power the transport of molecules across a membrane.

Answer 9

Primary Active Transport

Question 10

Uses energy to transport particles across the membrane; however, there is no direct coupling to ATP hydrolysis. Instead, transport harnesses energy released by one particle going down its electrical gradient to drive a different molecule particle up its gradient.

Answer 10

Secondary Active Transport

Question 11

Occurs when the CELL MEMBRANE invaginates and engulfs material to bring into the cell (which gets incased into a vesicle).

Answer 11

Endocytosis

Question 12

The endocytosis of fluids and dissolved particles.

Answer 12

Pinocytosis

Question 13

The ingestion of large solids such as bacteria.

Answer 13

Phagocytosis

Question 14

Occurs when the secretory vesicles fuse with the MEMBRANE, releasing material from inside the cell to the extracellular environment.

Answer 14

Exocytosis