biology 1150 test two (plasma membrane)

Question 1

plasma membrane is the outer boundary of the cell which controls what

Answer 1

in and out movement

Question 2

what separates the extracellular fluid from the material contained in the cytoplasm inside the cell

Answer 2

the phospholipid bilayer

Question 3

what 3 things are also part of the membrane and give it the qualities of a fluid mosaic

Answer 3

proteins, cholesterol, carbohydrates

Question 4

the polar head of a phospholipid is _______ while a non-polar tail is ______

Answer 4

hydrophilic / hydrophobic

Question 5

what does the plasma membrane separate

Answer 5

internal living environment and external environment

Question 6

membranes function (5)

Answer 6

• maintain structural integrity of the cell
• regulate movement of substances into and out of the cell
• provide recognition between cells
• provide communication between cells
• stick cells together to form tissues and organs

Question 7

what class of biological macromolecule makes up the primary structure of the plasma membrane of a cell

a. protein
b. lipid
c. carbohydrate
d. nucleic acid

Answer 7

b. lipid

Question 8

what chemical characteristic of phospholipids allows them to form unique chemical layers

a. ionize easily
b. highly acidic because they easily release H+
c. extremely polar molecules
d. extremely hydrophobic molecules
e. both polar and non-polar regions

Answer 8

e. both polar and non-polar regions

Question 9

cell theory says

Answer 9

cells are the fundamental units of life

Question 10

what are the two types of movement across the plasma membrane

Answer 10

passive and active transports

Question 11

passive transport requires energy

a. true
b. false

Answer 11

b. false

Question 12

molecules move ____ the gradient (from area of higher concentration to an area of lower concentration) in passive transport

Answer 12

down

Question 13

movement requires energy in which type of transport

Answer 13

active

Question 14

molecules move up (against) the gradient in

Answer 14

active transport

Question 15

what is tonicity

Answer 15

relative concentration of solutes dissolved in solution

Question 16

what side of the membrane has the higher solute concentration

Answer 16

hypertonic

Question 17

water will always move toward the ____ solute concentration

Answer 17

higher

Question 18

what is simple diffusion

Answer 18

movement of a substance following a concentration gradient (from high to low)

Question 19

what is the end result of simple diffusion

Answer 19

equal distribution of the substance in two areas

Question 20

what does simple diffusion eliminate

Answer 20

concentration gradient

Question 21

what is facilitated diffusion

Answer 21

substance moves from a region of higher concentration to a region of lower concentration with the aid of a membrane protein

Question 22

what proteins help water soluble substances cross a cell membrane

Answer 22

carrier proteins

Question 23

what is osmosis

Answer 23

diffusion of water

Question 24

can water cross the cell membrane

Answer 24

yes

Question 25

can large polar molecules (glucose, sucrose) or ions cross the cell membrane

Answer 25

no

Question 26

the only way to equalize the concentration is to

Answer 26

move water toward the higher concentration to dilute solute

Question 27

example of active process

Answer 27

Na+/K+ pump

Question 28

what happens in exocytosis

Answer 28

cells package molecules in vesicles to spill out

Question 29

endocytosis consists of what two processes

Answer 29

phagocytosis and pinocytosis

Question 30

what happens in phasgocytosis

Answer 30

cells engulf bacteria or other large particles

Question 31

what happens in pinocytosis

Answer 31

cells engulf droplets of extracellular fluid and the dissolved substances therein

Question 32

what type of transport through the plasma membrane listed below is active

a. osmosis
b. facilitated diffusion
c. Na+/K+ pump
d. simple diffusion
e. endocytosis

Answer 32

e. endocytosis

Question 33

what substance from the list would not need a transporter to passively cross the plasma membrane

a. oxygen
b. glucose
c.. sodium
d. potassium
e. sucrose

Answer 33

a. oxygen