Chap. 7

Question 1

A cell must exchange materials with its surroundings, a process controlled by the

Answer 1

plasma membrane

Question 2

plasma membrane

Answer 2

is the boundary that separates the living cell from its surroundings

Question 3

Plasma membrane exhibits

Answer 3

selective permeability

Question 4

selective permeability

Answer 4

regulating the cell’s molecular traffic, allowing some substances to cross it more easily than others

Question 5

Phospholipids are the most abundant lipid in the

Answer 5

plasma membrane

Question 6

phospholipid (nonpolar)

Answer 6

are nonpolar (hydrophobic)

Question 7

phospholipid (polar)

Answer 7

hydrophilic (likes water)

Question 8

Membrane Structure and Function

Answer 8

Transport proteins are often responsible for controlling passage across cellular membranes

Question 9

the fluid mosaic model,

Answer 9

the membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids

Question 10

Membranes are held together mainly by weak

Answer 10

hydrophobic interactions

Question 11

peripheral proteins

Answer 11

proteins in one side of the plasma membrane

Question 12

Cholesterol

Answer 12

reducesmembrane fluidity atmoderate temperatures, but at low temperatureshinders solidification(lower cholesterol will not mke your body work normally).

Question 13

Unsaturated tailsprevent

Answer 13

packing.

Question 14

Saturated tails pack

Answer 14

together

Question 15

Isotonic

Answer 15

equal concentration of the solution inside and outside

Question 16

Hypertonic

Answer 16

he cell has a higher concentration of solutes than inside the cell (less water)

Question 17

Hypotonic

Answer 17

olute concentration of the external environment is lower than that of the cell’s internal environment

Question 18

Active transport

Answer 18

requires energy, usually in the form of ATP hydrolysis, to move substances against their concentration gradients