Ch 7-- Diffusion across Plasma Membrane

Question 1

What two things make up the cell boundary?

Answer 1

Lipids (3 kinds) & proteins (2 kinds)

Question 2

What are the three kinds of lipids?

Answer 2

Cholesterol, phospholipids, and glycolipids

Question 3

What are the two kinds of proteins?

Answer 3

integral and peripheral

Question 4

What makes up glycolipids?

Answer 4

carbs and lipids

Question 5

What is selective permeability?

Answer 5

only certain molecules can come in and go out of the plasma membrane

Question 6

What is a fluid mosaic model?

Answer 6

a montage of several proteins are embedded in a very fluid (mobile), phospholipid bilayer

Question 7

Both phospholipid & membrane proteins can do what in the plasma membrane?

Answer 7

move freely within the bilayer

Question 8

Is this lack of rigidity good or bad for the cell?

Answer 8

good, keeping processes in check such as Phagocytosis & cell signaling.

Question 9

Phospholipid make up how much much of the plasma membrane

Answer 9

75%

Question 10

An amphipathic molecule is made up of what?

Answer 10

hydrophilic and phobic structures

Question 11

It is a hydrophobic…. with a….region.

Answer 11

head…polar

Question 12

It is a hydrophilic…with a…region

Answer 12

tail…non-polar

Question 13

Cholesterol makes up…and glycolipids make up…of the plasma membrane.

Answer 13

20%…5%

Question 14

Cholesterol offers…

Answer 14

stability

Question 15

Hydrophobic molecules can pass the membrane freely?

Answer 15

yes, (hydrocarbons) dissolve in the lipid bilayer

Question 16

Hydrophilic molecules can pass through the membrane freely?

Answer 16

no, they need the help of a transport protein to act as a conduit

Question 17

Where are integral proteins found? What do they function as?

Answer 17

They span the membrane from the inside to the outside. They function as transport proteins, enzymes, or receptors.

Question 18

Where are Peripheral proteins found? What do they function as?

Answer 18

They are found on the surface of the plasma membrane. They function as enzymes & also play a role in cell-to-cell connections; DO NOT transport

Question 19

What is concentration gradient?

Answer 19

It is the difference in concentration of a substance from one area to another & is usually studied across plasma membrane of a cell

Question 20

Diffusion is the movement of a substance from a region of….to a region of….

Answer 20

High concentration…low concentration

Question 21

Facilitated diffusion is diffusion with the help of a…

Answer 21

transport protein.

Question 22

What is osmosis and which way does it diffuse?

Answer 22

It is the diffusion of water molecules across a selectively permeable membrane; it diffuses from a higher water concentrate to lower water concentrate.

Question 23

The ability of a solution to cause a cell to gain or lose water is what?

Answer 23

tonicity

Question 24

Hypertonic solution has a solute concentration… than that inside the cell=the cell…water.

Answer 24

greater…loses

Question 25

Hypotonic solution has a solute concentration... than that inside the cell=the cell...water.

Answer 25

less...gains

Question 26

Isotonic solution has a solute concentration is the...inside & outside of the cell= no net water moves across the membrane.

Answer 26

same

Question 27

What are the two types of transport proteins?

Answer 27

channel and carrier

Question 28

This transport protein acts as a gateway for molecules to pass through; ions/water goes down their concentration on gradient ex. aquaporin

Answer 28

channel

Question 29

This transport protein bind to molecules & change shape to shuttle them across the membrane; polar molecules-sugars & amino acids

Answer 29

carrier

Question 30

What are the two types of transport?

Answer 30

passive and active

Question 31

This type of transport moves substances from high to low concentration & does so without any input of energy (does not require ATP); down conc. gradient

Answer 31

Passive

Question 32

This type of transport moves substances from low to high concentration & with input energy in the form of ATP; goes against conc. gradient and requires ATP; ex: sodium-potassium pump/ proton pump.

Answer 32

Active

Question 33

ATP pumps that contributes to a membrane potential are?

Answer 33

Electrogenic pumps

Question 34

What and where is a sodium-potassium pump?

Answer 34

It transports 3 Na+ ions out of the cell & brings 2 K+ ions back into the cell for every cycle it runs. It is located in the plasma membrane (very active in nerve & muscular cells)

Question 35

Electrical and Concentration gradient equals.... which drives diffusion of ions across the membrane.

Answer 35

Electrochemical gradient

Question 36

What s co-transport?

Answer 36

depends on the ion gradient that the primary active created. once ions are on the other side of the membrane they fall down their conc. gradient (high to low)

Question 37

..... is used by a cell for transport of macromolecules, polysaccharides & proteins, in membrane sacs called.....

Answer 37

Bulk Transport..... vesicles

Question 38

Bulk transport requires ATP and is classified into 3 types:

Answer 38

endocytosis, exocytosis, and transcytosis

Question 39

Endocytosis transport of substances....the cell.

Answer 39

into

Question 40

.....transport of substance out of the cell.

Answer 40

exocytosis

Question 41

Transcytosis transports........of the cell

Answer 41

into, across & then out

Question 42

Phagocytosis, Pinocytosis, and Receptor- mediated are the three types of.....

Answer 42

endocytosis

Question 43

~"cell-eating" ~hydrolytic enzymes which were present in lysosome, start digesting the food after the formation of Phagolysosome

Answer 43

Phagocytosis

Question 44

~"cell-drinking" ~ in the folds on the plasma membrane forms a vesicle & brings the extracellular fluid & the dissolved solutes into the cell ~the vesicle fuses with an endosome & the cell then absorbs the dissolved solutes present in the fluid

Answer 44

Pinocytosis

Question 45

Receptor-mediated uses specific receptor proteins on a cell to......found outside the cell

Answer 45

bind molecules (ligand)