CH 7 Membranes and Transport

Question 1

PhosphoLipid bilayer

Answer 1

• Amphipathic
• Phosphate head (hydrophilic)
• Fatty Acid tails (hydrophobic)

Question 2

Major Membrane Component;

Answer 2

Proteins ( channels/ transport/ receptor/ structure)

Question 3

Minor Membrane components;

Answer 3

1. Sterols (membrane fluidity)

2. Oligosaccharides ( surface tags/ labels)

Question 4

Integral membrane proteins

Answer 4

1. Transmembrane (physically embedded)
2. Lipid anchored
3. May be bound to cytoskeleton (- movement)

Question 5

Peripheral membrane proteins

Answer 5

• no covalent bond

- only bound to polar head of phospholipids

Question 6

“FlipFlop”

Answer 6

movement from one leaflet to another (not spontaneous)

Question 7

Flippase

Answer 7

requires ATP to transport lipid from one leaflet to the other
(facilitates a flipflop)

Question 8

Factors Affecting membrane ‘fluidity’

Answer 8

1. length of fatty acid tails (shorter = +fluidity)
2. Presence of double bonds (+ fluidity)
3. Presence of sterols (more rigid)

Question 9

Glycosylation

Answer 9

Process of attaching a carb. to a protein or lipid w/ covalent bond

Question 10

Glycolipid

Answer 10

Carb bound to Lipid

Question 11

Glycoprotein

Answer 11

Carb bound to protein

Question 12

FFEM

Answer 12

Freeze Fracture Electron Microscope

used to analyze phospholipid bilayer

Question 13

P face (FFEM)

Answer 13

Protoplasmic; INSIDE cell (most actions occur here)

Question 14

E face (FFEM)

Answer 14

Extracellular face

Question 15

Lipid Exchange Proteins

Answer 15

extract lipid from 1 membrane to use in another

Question 16

Signal Peptide

Answer 16

protein directed to RER in early protein synthesis

Question 17

Signal peptidase

Answer 17

cuts off protein in R ER & removes signal peptide

Question 18

N Linked (Glycosylation)

Answer 18

Carb linked to Nitrogen (in Golgi or RER)

Question 19

O Linked (Glycosylation)

Answer 19

Sugars added to Oxygen (only in Golgi)

Question 20

Plasma membrane is …

Answer 20

selectively permeable

Question 21

Passive diffusion

Answer 21

solute thru membrane w/o transport protein (small & uncharged molecules)

Question 22

Facilitated Diffusion

Answer 22

Passage thru P Membrane w/ transport protein (large molecules)

Question 23

Active transport

Answer 23

• Requires ATP

- AGAINST concentration gradient

Question 24

Transmembrane Gradient

Answer 24

concentration of solute higher on one side of membrane than the other

Question 25

Ion electrochemical gradient

Answer 25

brain and heart function off this

Question 26

Tonicity

Answer 26

Concentration outside a cell relative to the inside

Question 27

Isotonic

Answer 27

= water & solute concentration on both sides

= net movement of H2O

Question 28

Hypertonic

Answer 28

Concentration higher OUTSIDE cell

• Cell shrinks
• Crenation (animals)
• Plasmolysis (plants)

Question 29

Hypotonic

Answer 29

Concentration of solute LOWER outside (high {H2O})

• Cell swells
• Osmolysis (Swelling to the point of bursting)

Question 30

OSMOSIS

Answer 30

Water diffusing through membrane from area of High to Low concentration

Question 31

Osmotic Pressure

Answer 31

tendency for water to move into any cell

Question 32

Transport Proteins

Answer 32

1. Channels (facilitated diffusion)

2. Transporters (ATP used)

Question 33

aquaporins

Answer 33

speed up water diffusion

Question 34

Primary Active transport

Answer 34

uses a pump (directly using ATP)

Question 35

Secondary Active Transport

Answer 35

Uses pre existing gardient

Question 36

Exo/ Endocytosis

Answer 36

Transport of bulk molecules in/ out of cell