Chapter 6: Cell Membranes

Question 1

a layer two molecules thick

Answer 1

bilayer

Question 2

a thin layer of lipids and proteins, separates a cell from its surrounding

Answer 2

plasma membrane

Question 3

form channels that allow selected polar molecules and ions to pass across a membrane

Answer 3

transport proteins

Question 4

the plasma membrane identify a cell as part of the same individual or as foreign

Answer 4

recognition proteins

Question 5

recognize and bind molecules from other cells that act as chemical signals, such as hormones

Answer 5

receptor proteins

Question 6

bind cells together by recognizing and binding receptors or chemical groups on other cells

Answer 6

cell adhesion proteins

Question 7

speed chemical reactions in membranes

Answer 7

enzymes

Question 8

lipid molecules with carbohydrate groups attached

Answer 8

glycolipids

Question 9

protein molecules with carbohydrate groups attached

Answer 9

glycoproteins

Question 10

the carbohydrate groups of the cell surface glycolipids and glycoproteins form a surface coat

Answer 10

glycocalyx

Question 11

proposes that the membrane consists of a fluid phospholipid bilayer in which proteins are embedded and float freely

Answer 11

fluid mosaic model

Question 12

embedded in the phospholipid bilayer

Answer 12

integral proteins

Question 13

held to membrane surfaces by noncovalent bonds

Answer 13

peripheral proteins

Question 14

biological membranes are….?

Answer 14

selectively permeable

Question 15

• diffusion through the lipid part of a biological membrane

- depends solely on molecular size and lipid solubility

Answer 15

simple diffusion

Question 16

-diffusion of polar and charged molecules through transport proteins in the hydrophobic lipid bilayer

Answer 16

facilitated diffusion

Question 17

integral membrane proteins that form hydrophilic channels in the membrane through which water and ions can pass

Answer 17

channel proteins

Question 18

channel protein that transport water

Answer 18

aquaporins

Question 19

• switch between open, closed, or intermediate states

- facilitate transport of ions (Na+, K+, Ca2+, Cl-)

Answer 19

gated channels

Question 20

• bind pecific single olute and transport it across the lipid bilayer
• undergo conformational changes that move the solute -binding site from one side of the membrane to the other
• can become saturated when there are too few transport proteins to handle all the solute molecules

Answer 20

carrier proteins