Biology Ch 4

Front 1

plasma membrane

Back 1

is a boundry of the cell that regulates the passage of molecules into and out of the cell, similar to a castle wall.

Front 2

plasma membrane is made of

Back 2

a phospholipid bilayer (fluid consistancy) with protein molecules embedded within but scattered (mosaic) throughout the lipid

Front 3

the model of the plasma membrane today

Back 3

fluid-mosaic model

Front 4

hydrophilic

Back 4

love water

Front 5

hydrophobic

Back 5

hate/fear water

Front 6

each phospholipid molecule has

Back 6

a polar (hydrophilic) head that is attracted to polar water and two nonpolar (hydrophobic) tails that face away from water and toward the tails of the other layer

Front 7

glycolipid

Back 7

similar to phospholipid but their head has a carbohydrate molecule attatched

Front 8

glycoprotein

Back 8

are inside proteins (integral) embedded in the membrane with carbohydrate chains that project externally; they are unique for cell identity

Front 9

proteins extending into the cell

Back 9

from the inside layer serve as links to cytoskeleton filaments

Front 10

plasma membrane has the consistency of

Back 10

olive oil

Front 11

protein channels

Back 11

allow molecules or ions to move acrossthe membrane

Front 12

carrier protein

Back 12

combine with a particular substance to move it across membrane

Front 13

receptor protein

Back 13

bind to a specific molecule (hormone) due to its shape

Front 14

enzymatic protein

Back 14

carry out specific metobolic reactions. help catalyze

Front 15

different cells and tissues are recognized by

Back 15

their different surface carb chains; individuals in same species differ even more.
transplant tissues are recognized by the immune system because of these surface differences

Front 16

plasma membrane regulates

Back 16

the ability of molecules to enter or leave the cell

Front 17

the membrane is permeable to

Back 17

water

Front 18

_______ have no difficulty passing through a lipid bilayer

Back 18

small noncharged molecule

Front 19

selectively permeable

Back 19

the plasma membrane is this becuase it ristricts what molecules can come thru

Front 20

_______ cannot fit through the membrane because _____

Back 20

large, charged particle

often cannot pass thru the hydrophobic part of the bilayer

Front 21

the ____ and ____ a molecule, the easier it passes the lipid bilayer

Back 21

smaller and more oil soluble (nonpolar)

Front 22

____ and ____ help large and polar molecules across

Back 22

channel and carrier proteins

Front 23

__________ does not require energy

Back 23

passive transport

Front 24

________ does require energy.

Back 24

active transport

Front 25

__________ is a physical process where molecules move down a concentration gradient from higher to lower concentration untill equal distribution

Back 25

diffusion

Front 26

diffusion applies to:

Back 26

any type of molecule

Front 27

_______ pass easily through the lipid membrane

Back 27

lipid-soluble molecules (alcohols)

Front 28

__________diffuse easily through alveoli, capillaries, and blood plasma membranes.

Back 28

gasses such as oxygen and carbon dioxide

Front 29

implanted timed release capsules rely on ___ to distribute medication

Back 29

diffusion

Front 30

water passes through ___ in the plasma membrane

Back 30

protein channels

Front 31

________ is a net of movement of water molecules from a region of greater concentration to a region of lesser concentration across a ____________.

Back 31

osmosis
semi-permeable membrane

Front 32

due to osmosis what can occure in human body

Back 32

water is absorbed from human large intestine and taken up by blood

Front 33

tonicity

Back 33

refers to the strength of a solution in relationship to osmosis

Front 34

isotonic

Back 34

hold cells stale since solute concentration is same on both sides of the membrane; there is no net gain or loss of water and cells neiher swell nor shrink. for example, red blood cells are isotonic in .9% NaCl

Front 35

hypotonic

Back 35

cause cells to swell; the solution has a lower percentage of solute (more water) than the cell. this causes the cell to swell and it may burst (lysis) if it is an animal cell due tot he intake of water. for example, red blood cells any slution less thatn .9% NaCl will cause hemolysis (burst).

Front 36

turgor pressure

Back 36

brought about by hypotonic solutions. pressure against cell wall. plant cells do not burst due tot he ridig cell wall. turgor pressure keeps plant celss erect

Front 37

hypertonic

Back 37

allow cells to shrivel; the solution has a higher percetage of solute (less water) outside the cell, causing the cell to shrink due to net movement of water outward. for example, any solution with concentration higher than .09% causes RBCs to shrink (termed crenated)

Front 38

crenation

Back 38

shrinking of cytoplasm in animal cell due to osmosis

Front 39

plasmolysis

Back 39

shrinking of cytoplasm in a plant cell due to osmosis

Front 40

carrier proteins

Back 40

are specific; can eachc ombine with only a certain type of molecule, which is transported through the membrane, probably by undergoing a change in shape

Front 41

facilitated diffusion

Back 41

occurs when certain sugars and amino acid molecules are transported across the membrane by a carrier protein down a concentration gradient at a faster rate than simple diffusion; this does not need energy

Front 42

active transport

Back 42

transports molecules across a membrane against the concentration gradient from a lesser to a greater concentration, and i requires energy (ATP)

Front 43

must be enclosed in a vesicle for transport

Back 43

large molecules including polypeptides, polysachrides, and polynucleotides are too large to by transportd by a carrier protein

Front 44

endocytosis

Back 44

occurs when the plasma membrane fors a vesicle around a substance to be takein into the cell; requires eneryg.

Front 45

phagocytosis

Back 45

endocytosis
large sized materials taken into the cell
cell eating
ex: macrophages engulf bacteria and worn-out red blood celss

Front 46

pinocytosis

Back 46

endocytosis
liquids or small molecules such as proteins taken into cell
cell drinking
requires use of electron microscope to observe

Front 47

exocytosis

Back 47

revers of endo cytosis
intercellular vesicles formed by golgi transports cell products out of the cell when vesicle fuses with plasma membrane;
required for secretion

Front 48

the plasma membrane is a this sheet of lipid embedded with larger molecules called

Back 48

protein

Front 49

if a cell has the same concetration of dissolved molecules as that of its outside environment, the cell's condition is described as

Back 49

isotonic

Front 50

all of the following protein classes are found as components of membranes EXCEPT
carrier proteins
hormone proteins
receptor proteins
channel proteins
enzymatic proteins

Back 50

hormone proteins

Front 51

in bacteria, fungi, and pants the high internal pressure generated by osmosis is counteracted by the mechanical strength of their

Back 51

cell wall

Front 52

the type of diffusion that is specific o water and passive is

Back 52

osmosis

Front 53

which of the following is NOT a component of an animal cell membrane
phospholipid bilayer
polynucleotides
glycoprotein
glycolipids
cholesterol

Back 53

polynucleotides

Front 54

when a substance has equal concentration throughout a space it is called

Back 54

equilibrium

Front 55

which of the following molecules will have thr most difficult time getting through the phospholipid bilayer?
a molecule of water
a small, nonpolar molecule
a large, nonpolar molecule
a lipid
a sodium ion

Back 55

a sodium ion

Front 56

a substance that is attracted to water is called

Back 56

hydrophilic

Front 57

describe the phospholipid bilayer bilayer and the various types of proteins

Back 57

the cell membrane is made of a phospholipid bilyaer with different proteins embedded in it. cholesteral can also be found in the membrane along with carbs attached to the lipids and proteins

Front 58

why is a cell membrane called differentially permeable?

Back 58

passage through the protein channels is selective therefor making the membrane diffferentially permeable (or selectively permeable)

Front 59

what are the mechanisms by which substances enter and exit cells?

Back 59

passive: simple diffusion, facilitated diffusion, osmosis
active: active transport, endocytosis: phagocytosis, pinocytosis, exocytosis

Front 60

define diffusion and give an example

Back 60

the net monement of a substance from a region of higher concentration to a region of lower concentration ex: crystal dye placed in water

Front 61

osmosis

Back 61

the diffusion of water across a differentially permeable membrane

Front 62

isotonic

Back 62

solute concentration same on both sides of membrane

ex: .9% salt sodium chloride and blood neither shrink nor swell

Front 63

hypotonic

Back 63

solutions casuin cells to swell or burst due to intake of water

ex: salt solution lower than .9% with blood

Front 64

hypertonic

Back 64

solutions causing cells to shrink due to loss of water

10% solution of NaCl

Front 65

both plant and animal celss have a cell membrane, but plant celss also have a cell

Back 65

wall

Front 66

molecules diffuse down a

Back 66

concentration gradient

Front 67

in a hypertonic solution cells ___ water and the cell contants ____.

Back 67

lose

shrivel up

Front 68

when plant cells are placed in a hypotonic solution, ____ is obvious because cell contents ___ against the cell wall.

Back 68

swelling, push

Front 69

during ___ diffusion, carriers move glucose and amino acids down their concentration gradients.

Back 69

facilitated