Lec 13 - Cell Membranes: Structure and Function

The inner leaflet has more _________ charged heads, which ______ transport

negatively, limits

Define polarity

one side is not like the other

What makes the inner leaflet more negatively charged?

phosphatidylserine

T/F? Lipids create stiffness in the membrane

True

What role does cholesterol have in the cell membrane?

alters stiffness/fluidity/movement depending on temp to create a stable middle ground the cell is flexible yet firm

T/F? Sugars (glycoprotein) are important since they change the functionality of the protein that are inserted into the membrane or the phospholipid itself

True

What is spectrin

structural protein that is inner leaflet membrane associated

Spectrin forms _____ chains and ____ to membrane proteins

long, anchor

What are some types of membrane domains

lipid rafts, caveolae

What are there a lot of at lipid raft sections?

Cholesterol and proteins

When platelets are stimulated by ______ or _______, they change shape and lipid raft ______

collagen, thrombin, aggregates

caveolae are found in close association with ______

cholesterol

What molecules need transporters

large (uncharged) and ions (charged)

What are the 5 types of transport

simple diffusion

(facilitated diffusion)

• channel-mediated diffusion

• carrier-mediated diffusion

active transport

electrochemical gradient

What are the 5 transporters (A.U.S.)

• carrier proteins

Uniport

Antiport

Symport

• channel proteins

gated channel

open channel

What is a uniport

transports one thing

What is an antiport

“1” in “1” out

What is a symport

it goes along

Fick’s Law of Diffusion specifies what properties

surface area

concentration gradient

membrane permeability

membrane thickness

Diffusion is _____ along higher concentration gradients, over _____ distances, at ______ temperatures, for _______ molecules

faster, shorter, higher, smaller

Passive Membrane Transport - Facilitated Diffusion

transported substances bind carrier proteins or pass through protein channels

T/F? Membrane transport proteins/carrier proteins are integral transmembrane proteins

True

Membrane transport proteins/carrier proteins show ______ for certain polar molecules including ______ and _______

specificity, sugar, amino acids

Gated Channel

usually closed, highly selective

Active Transport

transport against a concentration gradient, requires energy

What are the two forms of active transport

primary active

secondary active