Membranes and Membrane Transport

Why is the phospholipid head hydrophilic (water loving)

It is charged both negative and positive making it polar

What is the approximate electrochemical gradient across the lipid membrane?

-60mV

What is fluid packing?

Fluid packing refers to how phospholipids in a cell membrane are arranged and move

What do proteins in membranes do?

cell surface receptors

channels/proteins

enzymes!

What do carbohydrates in membranes do?

Always on the outer surface of the membrane (extracellular)

Can create glycolipids/glycoproteins

Act as recognition sites [cell marker/ID tag]

What are integral proteins

embedded within the membrane

amphipathic

includes trans membrane proteins

What are peripheral proteins

non-embedded

lack exposed hydrophobic groups

binds to the heads of phospholipids

What are lipid-anchored proteins

attach directly to the fatty acids within phospholipids

What are the 4 ways to cross a membrane

diffusion, facilitated diffusion, active transport, secondary active transport

What are the two classifications of channel proteins

gated or non-gated

What are the 3 classifications of carrier proteins

uniporter, symporter, antiporter

What are examples of how a gated channel protein can open

mechanically, voltage activated

What way does a Na/K pump work

3 Na out for every 2 K in

What type of carrier protein is the Na/K pump

antiporter

How does glucose enter the cell

The symporter brings in glucose alongside Na after it is purged by the cell by the Na/K pump, which creates a concentration gradient

What are the 3 types of endocytosis

Phagocytosis, Pinocytosis, Receptor Mediated

How does receptor mediated endocytosis work?

ligands on molecules bind to receptors

What process forms a phagocytotic vaccuole

Cytoplasm flows around the particle by polymerisation and depolymerisation of actin microfilaments

Clathrin-coated pits form in the cell membrane during in the process of…

receptor-mediated endocytosis

The difference between a carrier protein and a channel protein is that…

a carrier proteins bind to the substance being transported while channels only interact very weakly with the transported material

What is pinocytosis

The cell takes in liquid and dissolved substances.