Unit 4: The Plasma Membrane

Question 1

Cell membrane are made of

Answer 1

Phospholipids

Question 2

Phospholipids have a hydro__________, [polar/nonpolar] head

Answer 2

Hydrophilic; polar

Question 3

Phospholipids have hydro__________, [polar/nonpolar] tails

Answer 3

Hydrophobic; nonpolar

Question 4

The cell membrane is selectively __________

Answer 4

Permeable

Question 5

Only very __________ molecules can pass directly between the phospholipids

Answer 5

Small

Question 6

Large molecules have to pass through __________ to get through the cell membrane

Answer 6

Transport proteins

Question 7

The three major types of transport proteins are __________, __________, and __________

Answer 7

Channel, carrier, and pump

Question 8

The lipid bilayer is described as __________ mosaic

Answer 8

Fluid

Question 9

Glycoproteins

Answer 9

Allow cells to communicate with others in
close proximity

Question 10

Cholesterol, found ONLY in animal cell membranes, helps maintain

Answer 10

Fluidity

Question 11

Active transport moves molecules across the cell membrane __________ energy

Answer 11

With

Question 12

Passive transport moves molecules across the cell membrane __________ energy

Answer 12

Without

Question 13

In passive transport, molecules move from an area of __________ concentration to an area of __________ concentration
(In other words, __________ the concentration gradient)

Answer 13

High —-> low; down

Question 14

__________ is the simplest form of passive transport

Answer 14

Diffusion

Question 15

__________ is reached when diffusion has caused molecules to spread out evenly

Answer 15

Equilibrium

Question 16

__________ proteins are like open doorways in passive transport

Answer 16

Channel

Question 17

__________ proteins open and close in response to specific molecules in passive transport

Answer 17

Carrier

Question 18

Solute

Answer 18

The substance dissolved in a liquid

Question 19

Solvent

Answer 19

The liquid that dissolves the solute

Question 20

Solution

Answer 20

The mixture of solute and solvent

Question 21

In __________, water molecules diffuse through a membrane in response to a concentration gradient

Answer 21

Osmosis

Question 22

Water always moves toward an area of __________ SOLUTE concentration (high to low WATER concentration)

Answer 22

Higher

Question 23

__________ describes relative concentrations of solute

Answer 23

Tonicity

Question 24

Hypertonic

Answer 24

Concentration is higher relative to something else

Question 25

Hypotonic

Answer 25

Concentration is lower relative to something else

Question 26

Isotonic

Answer 26

Both concentrations are equal

Question 27

Active transport requires __________

Answer 27

ATP

Question 28

Active transport pumps molecules __________ the concentration gradient

Answer 28

Against

Question 29

Endocytosis

Answer 29

The process of entering a cell

Question 30

Exocytosis

Answer 30

The process of exiting a cell

Question 31

Phagocytosis

Answer 31

“Cell eating,” cell takes in large solid particles

Question 32

Pinocytosis

Answer 32

“Cell drinking,” cell takes in liquids

Question 33

Oxygen and carbon dioxide enter and exit the body by __________ through the membranes of lung cells, blood vessels, and red blood cells

Answer 33

Diffusing

Question 34

Blood glucose concentration (blood sugar) is regulated by the release of hormones through the cell membrane via __________

Answer 34

Exocytosis