Membranes

Question 1

separates the extracellular fluid from the cell interior

Answer 1

Plasma (Cell) Membrane

Question 2

regulates what passes into and out of the cell

Answer 2

selectively permeable

Question 3

Cell membranes are made up of a ___________

Answer 3

a lipid bilayer and various proteins

Question 4

lipid bilayer is made up of ________

Answer 4

phospholipids

Question 5

The lipid bilayer also contains ________, which provides stability and also lubricates the fatty acid tails

Answer 5

cholesterol

Question 6

phosphate group-

Answer 6

polar (hydrophilic) head

Question 7

fatty acids-nonpolar

Answer 7

(hydrophobic) tail

Question 8

gives the membrane its flexible and fluid characteristics

Answer 8

The lipid bilayer

Question 9

is self-sealing when punctured

Answer 9

the membrane

Question 10

can fuse with the membrane

Answer 10

vesicles

Question 11

removes items from cell

Answer 11

exocytosis

Question 12

bits of membrane can pinch off and become ______

Answer 12

vesicles

Question 13

takes items into the cell

Answer 13

endocytosis

Question 14

protein icebergs floating in a sea of lipids

Answer 14

The Fluid Mosaic Model

Question 15

main structure is the __________ with hydrophilic heads and hydrophobic tails

(The Fluid Mosaic Model)

Answer 15

phospholipid bilayer

Question 16

proteins and lipids are embedded in the______ (cholesterol provides stability)

Answer 16

bilayer

The Fluid Mosaic Model

Question 17

carbohydrates attach to the __________

Answer 17

outer surface

Question 18

cytoskeleton attaches to the __________

Answer 18

inner surface

Question 19

certain small water soluble molecules can simply pass through

Answer 19

channel proteins

Transport Proteins

Question 20

selective due to charge of molecule and channel protein

Answer 20

channel proteins

Transport Proteins

Question 21

some channels are “gated” – can open and close if charges change

Answer 21

channel proteins

Transport Proteins

Question 22

can move larger molecules across the membrane by changing shape

Answer 22

carrier proteins

Transport Proteins

Question 23

specific shape for certain molecules or ions

Answer 23

carrier proteins

Transport Proteins

Question 24

bind with specific molecules (like a lock and key), which causes the cell to change its activity

Answer 24

Receptor Proteins

Question 25

help the body to recognize “self” vs. foreign cells, as a function of the immune system

Answer 25

Recognition Proteins (Identity Markers)

Question 26

catalyze chemical reactions

Answer 26

Enzymes

Question 27

allow for support, shape and movement of cells

Answer 27

Cytoskeletal Proteins

Question 28

hold cells together, forming tissues and organs

Answer 28

Cell Adhesion Proteins

Question 29

does not require ATP energy

Answer 29

Passive Transport

Question 30

molecules move along the concentration gradient, from higher to lower concentration

Answer 30

Passive Transport

Question 31

may or may not require a transport protein

Answer 31

Passive Transport

Question 32

molecules must be small with no electrical charge

Answer 32

simple diffusion

Question 33

uses a protein to get through the lipid bilayer

Answer 33

facilitated diffusion

Question 34

allow nonlipid molecules through

Answer 34

channel proteins

Question 35

are always open

Answer 35

leak channels

Question 36

are closed unless stimulated to open

Answer 36

gated channels

Question 37

are very specific regarding the type and number of molecules that are allowed through

Answer 37

carrier proteins

Question 38

requires ATP energy

Answer 38

Active Transport

Question 39

moves molecules against the concentration gradient, from lower to higher concentration

Answer 39

Active Transport

Question 40

requires carrier proteins which change shape to move molecules across the membrane, or else involves vesicles (endocytosis and exocytosis)

Answer 40

Active Transport

Question 41

carrier proteins can move larger molecules across the membrane by _________

Answer 41

changing shape