Ch. 4 Homeostasis And Transport

Question 1

Passive transport

Answer 1

The movement of substances across the membrane that does not require any energy

Question 2

Diffusion

Answer 2

The movement of molecules from an area of higher concentration to an area of lower concentration

Question 3

Concentration gradient

Answer 3

The difference in concentration of molecules across a space

Question 4

Concentration

Answer 4

The amount of something

Question 5

How do molecules reach equilibrium?

Answer 5

Molecules move down a concentration gradient from regions of [high] to [low]; concentration of a substamce is qual throughout a space

Question 6

The ability of a molecule to diffuse across a cell membrane depends on what two factors?

Answer 6

Size and polarity

Question 7

How does the size affect diffusion across the membrane?

Answer 7

A molecule must be very small to pass through the lipid bilayer or to pass through the proteins in the lipid bilayer

Question 8

How does polarity affect diffusion across the membrane?

Answer 8

A nonpolor molecule can slip through the nonpolar portion of the lipid bilayer. A protein must pass through a protein in the lipid bilayer

Question 9

Osmosis

Answer 9

Passive transport of water where water moves from [high] to [low] of water; diffusion of water through a selectively permeable membrane

Question 10

The direction of osmosis depends on what?

Answer 10

The concentration of dilutes on the two sides of the membrane

Question 11

Hypertonic solution

Answer 11

A solution with a [higher] gradient (more solutes); causes an animal cell to shrink

Question 12

Hypotonic solution

Answer 12

A solution with a lower concentration gradient (less solutes); causes an animal cell to swell

Question 13

Isotonic

Answer 13

When equilibrium is reached; produces no change in animal cell volume

Question 14

Water always moves via osmosis from what to what?

Answer 14

Hypotonic region to hypertonic region

Question 15

What are some materials that can pass through the lipid bilayer?

Answer 15

• small uncharged molecules Ex. O2 and CO2 • non polar molecules

Question 16

What materials cannot pass through the lipid bilayer?

Answer 16

•large molecules Ex. Proteins • charged materials Ex. Ions and salts

Question 17

How does the membrane separate the water bodies?

Answer 17

It is water insoluble

Question 18

The membrane is made of lipids that are…

Answer 18

Water insoluble molecules

Question 19

Facilitated diffusion

Answer 19

the movement of molecules down their concentration gradient through cell membrane proteins called carrier or channel proteins

Question 20

What are the three types of passive transport?

Answer 20

diffusion, facilitated diffusion, and osmosis

Question 21

what are aquaporins?

Answer 21

the carrier proteins that allow for water to pass through the cell membrane

Question 22

what do ion channels do?

Answer 22

transport ions like Na+, Ca2+, K+ and Cl- down their concentration gradients; transport protein through which ions can pass

Question 23

what is active transport?

Answer 23

the movement of molecules against their concentration gradient; requires energy

Question 24

The sodium potassium pump is what kind of protein?

Answer 24

trans-membrane protein

Question 25

The binding and release of sodium or potassium ions are due to what?

Answer 25

The binding and release of sodium or potassium ions are due to the conformational changes in the protein.

Question 26

the sodium potassium pump is powered by

Answer 26

ATP

Question 27

how does the sodium potassium pump mantain the concentration gradient?

Answer 27

by pumping 3 Na+ out of the cell and by pumping 2 K+ into the cell

Question 28

the sodium potassium pump creates what kind of gradient?

Answer 28

a electrochemical gradient

Question 29

what is an electrochemical gradient

Answer 29

when the outside of the cell is slightly more positive than the inside

Question 30

what are endocytosis and exocytosis?

Answer 30

macromolecules that are too big to pass though the cell mebrane and must enter by a different mechanism

Question 31

what is endocytosis?

Answer 31

the process by which cells ingest large particle; movement of a substance by a vesicle to thr inside of a cell ex: food

Question 32

give an example of endocytosis

Answer 32

white blood cells ingest bacteria

Question 33

what are the two types of endocytosis.

Answer 33

pinocytosis and phagocytosis

Question 34

what is pinocytosis?

Answer 34

the ingestion of liquids

Question 35

what is phagocytosis

Answer 35

the ingestion of solid particles

Question 36

if the fluid outside the cell is isotonic what happens to the cell?

Answer 36

the cell stays the same size

Question 37

if the fluid outside the cell is hypotonic then the cell....

Answer 37

if the fluid outside the cell is hypotonic then the cell will swell and burst.

Question 38

if the fluid outside the cell is hypertonic then the cell will

Answer 38

if the fluid outside the cell is hypertonic then the cell will shrink

Question 39

carrier protein

Answer 39

protein used to transport specific substances

Question 40

second messenger

Answer 40

acts as a signal molecule in the cytoplasm

Question 41

exocytosis

Answer 41

movement of a substance by a vesicle to the putside of a cell

Question 42

receptor protein

Answer 42

binds to a signal molecule, enabling the cell to respond to the signal molecule

Question 43

what do endocytosis and exocytosis have in common?

Answer 43

both require energy

Question 44

does diffusion require ATP? Channel protein required?

Answer 44

no and no

Question 45

does osmosis require energy? channel protein required?

Answer 45

no and yes aquaporins

Question 46

does facilitated diffusion require energy? channel protein required?

Answer 46

no and yes vesicle

Question 47

does exocytosis require ATP? channel protein required?

Answer 47

yes and no

Question 48

does endocytosis require energy? channel protein required?

Answer 48

yes and none

Question 49

does the sodium-potassium pump require energy? channel protein required?

Answer 49

yes and yes vesicle

Question 50

plasmolysis

Answer 50

the contraction or shrinking of the cell membrane of a plant cell in a hypertonic solution in response to the loss of water by osmosis

Question 51

hypotonic

Answer 51

when the solute concentration outside the cell is lower than that in the cytosol; water will diffuse into the cell

Question 52

hypertonic

Answer 52

when the solute concentration outside the cell is higher than that in the cytosol; water will diffuse out of the cell

Question 53

contractile vacuole

Answer 53

in protists, an organelle that accumulates water and then releases ir periodically to maintain osmotic pressure

Question 54

turgor pressure

Answer 54

the pressuire that is exerted on the inside of cell walls and that is cause by the movement of water into the cell

Question 55

cytolysis

Answer 55

the bursting of a cell

Question 56

sodium-potassium pump

Answer 56

a carrier protein that uses ATP to actively transport sodium ions out of a cell and potassium ions into the cell

Question 57

vesicle

Answer 57

a small cavity or sac that contains materials in a eukaryotic cell; forms when part of the cell membrane surrounds the materials to be taken into the cell or transported within the cell