pre lab 3

Question 1

plasma membrane of a cell is selectively permeable or…

Answer 1

semipermeable

Question 2

plasma membrane

Answer 2

allows some substances to pass through
prevents the passage of other substnaces

Question 3

concentration gradient

Answer 3

determines the direction of the net movement of a molecule or ion across the membrane when membrane is permeable to a given molecule of ion

Question 4

osmosis

Answer 4

diffusion of water across a semipermeable membrane

Question 5

water diffuses from areas of _____ concentration to areas of _____ concentration down its ___________

Answer 5

higher,
lower,
concentration gradient

Question 6

in lab we will use _______ as a semipermeable membrane to investigate osmosis

Answer 6

dialysis tubing

Question 7

place _____ in a variety of solutions and observe the osmotic effects in RBCs

Answer 7

erythrocytes

Question 8

RBCs

Answer 8

red blood cells

Question 9

if the plasma membrane is not permeable to the solute,

Answer 9

only water will move in or out of the cells through the plasma membrane and transmembrane proteins like aquaporins

Question 10

hypertonic solution

Answer 10

solution with lower water concentration because it has more solutes that the interior of the cells

cells in it will lose water and crenate (shrivel)

Question 11

hypotonic solution

Answer 11

a solution with a higher water concentration because it has fewer solutes than the cells

cells in it will gain water, swell and may lyse (burst)

Question 12

lysis with RBCs is called

Answer 12

hemolysis

Question 13

isotonic solution

Answer 13

a solution with the same concentration of solutes inside and outside of the cell

cells in it would have no net movement of water

Question 14

molecular mass

Answer 14

a factor that determines the permeability of solutes through a semipermeable membrane

Question 15

if solute is large, it _____ diffuse through the membrane easily or at all

Answer 15

does not

Question 16

polarity

Answer 16

another factor that affects solute permeability

solutes that are polar and therefore hydrophilic do not pass through the plasma membrane (that consists of lipids bilateral with a hydrophobic interior of fatty acids) easily.

Question 17

homeostasis

Answer 17

interval environment regulation

Question 18

diffusion

Answer 18

movement down a concentration gradient
can happen in liquids and gasses
greater the gradient the faster the diffusion
speed is directionally proportional to temperature
speed is inversely proportional to molecular weight

Question 19

osmosis

Answer 19

diffusion of water across a selectively permeable membrane

Question 20

membranes are made up of _____ components

Answer 20

several

Question 21

lipid bilayer of cell membrane are made up of…

Answer 21

hydrophilic phosphate heads (oriented to exterior)
hydrophobic fatty acid tails (oriented to interior)

Question 22

lipid bilayer of cell membrane keeps out most…

Answer 22

polar molecules
charged molecules
anions cross easier than cations

Question 23

semipermeable membrane allows…

Answer 23

certain molecules or ions to pass through by diffusion

rate is dependent upon
pressure
concentration
temperature
membrane permeability to the molecule
size and charge

Question 24

tonicity

Answer 24

measure of the effective osmotic pressure gradient

Question 25

hypotonic solution tonicity means

Answer 25

more molecules inside the cell than outside

Question 26

isotonic solution tonicity

Answer 26

no molecules in or out

Question 27

hypertonic solution

Answer 27

more molecules outside than inside the cell

Question 28

experiment 1

Answer 28

osmosis across a semipermeable membrane observing the movement of water across the membrane in response to sugar (which cannot pass through the membrane because it is too large) it’s time consuming dry the bag for each subsequent weight measurement

Question 29

experiment 2

Answer 29

RBC membrane permeability and osmosis place sheep’s blood into three different solutions to look at tonicity wear gloves obvi you’re looking at the passage of water in and out of the rbc since NA and Cl cannot cross the membrane due to their charge

Question 30

effect of molecular polaris on rbc membrane permeability

Answer 30

look at polaris of molecules effect on permeability across the rbc membrane

Question 31

effect if molecular size on rbc membrane permeability

Answer 31

use 3 iso-osmotic solutions polarity is similar but their size is different ethylene glycol glycerol glucose

Question 32

dialysis

Answer 32

the case of passive movement in which one type of solute is separated from another type of solute (both in the same solution) by a selectively permeable membrane that allows one type of solute to pass but not the other

Question 33

dialysis tubing

Answer 33

an artificial semipermeable membrane material with pore sizes that allow only small molecules to pass through comes in various pore sizes our pore size traps sucrose in starting location

Question 34

lyse

Answer 34

hypotonic burst

Question 35

crenate

Answer 35

hypertonic shrivel