LO5

Question 1

cell membranes are made of a

Answer 1

bilayer of phospholipids

Question 2

model where bilayer of phospholipids are constantly in motion

Answer 2

fluid mosaic model

Question 3

are self-sealing and fuse with other cell membranes

Answer 3

cell membranes

Question 4

when the cell membrane spontaneously round up to form vesicles

Answer 4

self-sealing

Question 5

fluidity buffer in animals

Answer 5

cholesterol

Question 6

cholesterol at low temperatures

Answer 6

acts as a spacer between fatty acid tails

Question 7

cholesterol restricts

Answer 7

van der walls interactions solidifying the membrane

Question 8

cholesterol at high temperatures

Answer 8

keeps membranes stable by preventing phospholipids from moving to much

Question 9

the ___ group of a cholesterol molecule interacts with the ___ head of a phospholipid to limit its movement

Answer 9

polar; polar

Question 10

_____ proteins are firmly embedded in the lipid bilayer

Answer 10

integral

Question 11

____ are at either surface of the bilayer

Answer 11

peripheral

Question 12

integral proteins are

Answer 12

amphipathic

Question 13

some proteins extend from

Answer 13

one side of a membrane to the other

Question 14

short carbohydrate chains are often attached to what?

Answer 14

to the extracellular surface of membrane lipids and proteins

Question 15

short carbohydrate chains form

Answer 15

glycolipids and glycoproteins

Question 16

cell membranes are permeable to

Answer 16

small nonpolar and some small polar molecules

Question 17

cell membranes are impermeable to

Answer 17

ions and larger polar molecules

Question 18

membrane proteins are required to transport these molecules

Answer 18

impermeable ions and larger polar molecules

Question 19

down their concentration gradient

Answer 19

higher to lower concentration

Question 20

particles are uniformly distributed but continue to move

Answer 20

dynamic equillibrium

Question 21

diffusion requires a

Answer 21

concentration gradient

Question 22

a concentration gradient is a form of ______ energy

Answer 22

potential

Question 23

osmosis is the _____ of water

Answer 23

diffusion

Question 24

tendency of a solution to take in water by osmosis

Answer 24

osmotic pressure

Question 25

high solute concentration = ____ effective water concentration = ____ osmotic pressure

Answer 25

low; high

Question 26

when solutions have an equal solute concentration

Answer 26

isotonic

Question 27

cells that have no net water movement

Answer 27

isotonic

Question 28

has a higher solute concentration

Answer 28

hypertonic solution

Question 28

cells will lose water and shrivel

Answer 28

hypertonic solution

Question 29

_____ proteins form hydrophilic channels for ion and H2O transport

Answer 29

Channel

Question 29

definition: if a cell wall is present (i.e. plant cell) the plasma membrane will shrink away from the cell wall

Answer 29

plasmolysis

Question 29

cell will take up water and may burst

Answer 29

hypotonic

Question 30

has a lower solute concentration

Answer 30

hypotonic

Question 30

channel proteins that transport H2O across cell membranes

Answer 30

aquaporins

Question 31

can be opened and closed in response to stimuli

Answer 31

ion channels that are gated

Question 32

___ proteins undergo a conformational change as they transport specific solutes across a cell membrane

Answer 32

carrier

Question 33

carrier proteins transport more ____ than channel proteins

Answer 33

slowly

Question 34

active transport moves materials from ___ to ____ concentrations

Answer 34

low to high

Question 35

_____________ pump transports Na and K ions against their gradient

Answer 35

sodium potassium

Question 36

sodium-potassium pump establishes an ______ gradient

Answer 36

electrochemical

Question 37

a ______ group from ATP is required for the pump to change shape

Answer 37

phosphate

Question 38

ejects substances from cells

Answer 38

exocytosis

Question 39

vesicle fuses with the plasma membrane and releases its contents outside the cell

Answer 39

exocytosis

Question 40

uptakes molecules or small cells by surrounding them with plasma membrane

Answer 40

endocytosis

Question 41

a ______ forms around the engulfed particles

Answer 41

vesicle

Question 42

a cell ingests a large particle (bacteria, food)

Answer 42

phagocytocis

Question 43

dissolved materials enter a cell enclosed in plasma membrane and gradually leak out

Answer 43

pinocytosis

Question 44

in this form of endocytosis membrane proteins with specific receptors bind with specific molecules to bring them into a cell

Answer 44

receptor-mediated endoxytosis

Question 45

______ is transported in the blood inside of LDL particles and is taken into cells via ____________

Answer 45

cholesterol, receptor mediated endocytosis

Question 46

how is cholesterol transported inside blood

Answer 46

1. LDL particles bind to specific receptors on plasma membrane 2. receptors and LDL particles are taken into the cell in a vesicle 3&4. receptors are recycled back to the plasma membrane via a vesicle 5. LDL particles are degraded by lysosomes

Question 47

membrane proteins from adjacent epithelial cells extend into the extracellular matrix and hold cells together

Answer 47

anchoring junctions

Question 48

prevent the passage of materials through the extracellular spaces between epithelial cells

Answer 48

tight junctions

Question 49

makes the lining of the intestines and blood-brain barrier

Answer 49

tight junctions

Question 50

hold cells together and allow for the exchange of ions and small molecules

Answer 50

cell junctions

Question 51

membrane proteins form channels between adjacent cells

Answer 51

gap junctions

Question 52

this is in animals, cardiac muscles cells, some nerve cells

Answer 52

gap junctions

Question 53

openings through the cell walls that connect the cytoplasms of adjacent plant cells

Answer 53

plasmodesmata

Question 54

facilitated diffusion is a form of _____ transport

Answer 54

passive

Question 55

concentration gradients are established by

Answer 55

active transport

Question 56

concentration gradients require

Answer 56

energy to build

Question 57

involve membrane proteins that may be linked to their cell's cytoskeleton

Answer 57

cell junctions