chapter 7

Question 1

does facilitated diffusion require energy

Answer 1

no

Question 2

what molecules aid in facilitated diffusion

Answer 2

carrier or channel proteins

Question 3

aquaporin

Answer 3

it is a hydrophilic channel in the protein that helps molecules get through by osmosis

Question 4

how do carrier proteins bring molecules into the cell

Answer 4

carrier protein changes shape to transport solutes (glucose to pancreas membrane)

Question 5

what is active transport

Answer 5

when a molecule goes against a concentrated gradient (low conc to high conc)

Question 6

what does active transport require that passive doesn’t

Answer 6

active:
requires energy (ATP)
must be a carrier protein
allows cells to maintain different concentration levels

Question 7

what is the sodium potassium pump

Answer 7

pumps 3 Na cations out of the cell and 2 K cations into the cell. Requires energy

Question 8

binding of K+ triggers what?

Answer 8

release of phosphate

Question 9

what is the role of a phosphate group in the S-P pump?

Answer 9

it allows the protein changes and releases Na+ out of the cell and removing the phosphate and returning to the original shape

Question 10

the binding of Na+ stimulates what?

Answer 10

ATP hydrolysis

Question 11

what side determines the charge of the cell membrane

Answer 11

cytoplasm side

Question 12

what can cause the membrane to be potentially negative?

Answer 12

unequal distribution of ions across the membrane, more negative ions on the inside of the cell

Question 13

movement of ions across the membrane is dependent on what two forces?

Answer 13

chemical force and electrical force

Question 14

what is chemical force?

Answer 14

ions concentration gradient

Question 15

what is electrical force?

Answer 15

effect of membrane potential on the ions movement

Question 16

what is electrochemical gradient?

Answer 16

combined forces of chemical and electrical

Question 17

net negative charge inside a cell and net chemical gradient favors what?

Answer 17

movement of Na+ into the cell

Question 18

what is proton pump?

Answer 18

continually pushing protons against gradient from inside of the cell to the outside

Question 19

the proton pump is used by which organisms?

Answer 19

plants, fungi, and bacteria

Question 20

the sodium potassium pump is used by which organisms?

Answer 20

animals

Question 21

is the proton pump active or passive transport?

Answer 21

active bc it requires energy

Question 22

where does the proton pump get its energy for its transport

Answer 22

the ATP potential energy is stored in membranes to be used when need be

Question 23

what is cotransport

Answer 23

the additional energy from the proton pump pushes the H+ and sucrose into the cell.

Question 24

how is ATP involved in cotransport

Answer 24

ATP is indirectly providing the energy necessary for cotransport (sucrose)

Question 25

exocytosis

Answer 25

large molecules exited by fusion of molecules to the plasma membrane

Question 26

endocytosis

Answer 26

the cell takes in new biological molecules and forming new vesicles from the plasma membrane

Question 27

phagocytosis

Answer 27

cell engulfs a particle of food or bacteria via pseudopodium to form a food vacuole

Question 28

pinocytosis

Answer 28

cell gulps droplets of extracellular fluid into tiny vesicles

Question 29

how is food digested

Answer 29

lysosome

Question 30

receptor mediated endocytosis

Answer 30

enables cells to acquire bulk quantities of specific substances

Question 31

ligand

Answer 31

molecule that binds specifically to a receptor site of another molecule

Question 32

familial hypercholesterolemia

Answer 32

inherited disease characterized by very high cholesterol levels in the blood

Question 33

tonicity

Answer 33

the ability of a solution surrounding a cell to cause that cell to gain or lose water

Question 34

free water

Answer 34

crosses selectively permeable membrane

Question 35

bound water

Answer 35

attached to hydrophilic parts of the solute molecules (sphere of hydration)-doesn't cross membrane

Question 36

osmosis

Answer 36

movement of water molecules across a selectively permeable membrane

Question 37

does osmosis require energy

Answer 37

no

Question 38

how does water move in a solute concentration

Answer 38

water moves from an area of lower to higher solute concentration

Question 39

equilibrium

Answer 39

solute molecules continue to cross membrane but at a similar rate in both directions

Question 40

Does diffusion require energy

Answer 40

no

Question 41

what is diffusion

Answer 41

the movement of a substances down its concentration gradient by random thermal

Question 42

what is passive transport

Answer 42

is one mechanism that moves molecules across cells

Question 43

what is considered "the edge of life"

Answer 43

plasma membrane

Question 44

what is selective permeability

Answer 44

allows some substances to cross more easily than other substances

Question 45

are organelles selective permeable?

Answer 45

yes

Question 46

fluid-mosaic model

Answer 46

currently the most accurate model to explain the structure of the plasma membrane

Question 47

how does the membrane represent "fluidity"

Answer 47

composed of a fluid phospholipid bilayer

Question 48

what allows cells to maintain unique internal environments

Answer 48

selective permeability of a plasma membrane

Question 49

how does the membrane represent "mosaic"

Answer 49

proteins are embedded or attached to the phospholipid bilayer

Question 50

what is the dynamically structured mosaic model

Answer 50

current model that emphasizes on mosaicism rather than fluidity. Membranes are more packed with proteins than originally thought

Question 51

how are membranes held together

Answer 51

WEAK hydrophobic interactions

Question 52

why does the plasma membrane need to be flexible

Answer 52

for things to be able to get through

Question 53

why can some proteins move across the plasma membrane

Answer 53

some proteins can't move because they are rigidly attached to the cytoskeleton and some aren't so they are more free

Question 54

what are the differences in saturated and unsaturated membranes

Answer 54

at low temps, saturated hydrocarbons solidify unsaturated hydrocarbons stay fluid

Question 55

what prevents hydrocarbons from solidifying

Answer 55

double bonds

Question 56

what is cholesterol's involvement in membranes

Answer 56

at low temps: keeps fluidity | at high temps: less fluid

Question 57

why is fluidity important for membranes

Answer 57

need to be fluid for molecules to get through, but not too fluid to lose shape

Question 58

how do enzymes move through membranes

Answer 58

they move laterally

Question 59

which types of proteins reach both outsides of the membrane

Answer 59

both, integral and peripheral proteins

Question 60

integral proteins

Answer 60

cross the plasma membrane (hydrophobic/philic regions)

Question 61

peripheral proteins

Answer 61

attached to the inner surface of the membrane some times via integral proteins

Question 62

how is the plasma membrane supported

Answer 62

attachments to cytoskeleton (microfilaments) on cytoplasmic side

Question 63

what does the plasma membrane attach to on the extracellular side, via the protein

Answer 63

collagen fibers and proteoglycans (which are attached to fibronectin)

Question 64

what are the 6 major functions of the membrane proteins

Answer 64

``` transport enzyme activity signaling transduction cell to cell recognition intercellular joining attachment to cytoskeleton and ECM ```

Question 65

membrane carbohydrates

Answer 65

usually short-branched polysaccharides (15

Question 66

glycolipids

Answer 66

lipids with carbohydrates covalently attached

Question 67

glycoproteins

Answer 67

proteins with carbohydrates covalently attached

Question 68

where are glycoproteins and glycolipids found

Answer 68

within membranes

Question 69

How does a transmembrane glycoprotein become embedded within plasma membrane

Answer 69

components of these membranes are synthesized within the ER

Question 70

Where are phospholipids and glycoproteins modified

Answer 70

Golgi

Question 71

what molecules move easily through the plasma membrane and why

Answer 71

molecules are non-polar and hydrophobic. They don't need aid of membrane proteins

Question 72

what molecules move difficultly through the plasma membrane and why

Answer 72

polar molecules because it is troubled in the hydrophobic environment