Bio-5A Membrane Structure And Function

Front 1

Membranes are built on ____bilayers, but they also contain ______&_________

Back 1

phospholipid, carbohydrate and protein.

Front 2

What is the fluid mosaic model? how was this shown?

Back 2

membranes are fluid structures in which some proteins can befound with hydrophobic parts in the middle and their hydrophilic parts outside. Shown through freeze fracture.

Front 3

What are peripheral membrane proteins? WHat are integral membrane proteins? What are transmembrane proteins?

Back 3

peripheral- outside of membrane. integral- portions go through. transmembrane- go completely through.

Front 4

portions found inside the lipid bilayer usually consist of....

Back 4

α-helices (shown in pink) that have hydrophobic amino acidside chains (1 and 2 at left). In bacteria, there can also be large ‘barrel’structures consisting of β-pleated sheets (blue structures in 3).

Front 5

CFTR is..
Mutation in this gene leads to...

Back 5

transmembrane protein- cystic fibrosistransmembrane conductance regulator.
cystic fibrosis (CF) (disrupts transport of Cl-mucus build up in the lungs, which leads to repeated lunginfections

Front 6

what is a glycoprotein? What is a glycolipid?

Back 6

proteins that have been covalently modified withcarbohydrates. lipids can also have covalent carbohydratemodifications, making them glycolipids.

Front 7

WHat did Frye and Eddin demonstrate? How did they do this?

Back 7

that proteins can move within membranes. Did this using a cultured mouse cell, human cell and the sendai virus.

Front 8

What are some determinants of membrane fluidity?

Back 8

Temperature (obvious) ,
^ cis bonds = membrane will retin fluidity at lower temps.
cholesterol (hydrophobic w/ small polar -OH) -- at ^ Temp, it restricts the movement of phospholipids= less fluid, low temp and it makes them more fluid.. Choolesterol buffers effects of T on phospholipids.

Front 9

Passive transport vs active transport.

Back 9

Passive: diffusion, no required energy, random collisions of particles, reaches equilibrium
Active: only carrier proteins, to keep certain solutes out and others in and to create electrochemical gradients. ex: Na/K pump, H+ pump.

Front 10

What is a channel protein and a carrier protein? What kind of diffusion are both of these proteins involved with? Is this still passive transport?

Back 10

Channel- protein that creates a hydrophilic tunnel through a membrane
Carrier- binds to particular substances and (by changing shape, allows a substance to enter a cell.
Facilitated diffusion. Yes`

Front 11

What are ion channels?

Back 11

a type of channel protein that allows ions to move across membranes.

Front 12

Osmotic pressure is only dependent on ...

Back 12

the concentration of solute

Front 13

What is isotonic, hypotonic, and hypertonic?

Back 13

iso- concentrations are approx equal (flaccid)
hypo- solution outside the cell has a lower solute conc. (lots of water/solvent in the cell-- lysed/turgid)
hyper- solution outside the cell has a higher solute conc. (shriveled/plasmolyzed)

Front 14

What is a cotransporter?

Back 14

a carrier protein that harnesses the energy of ionsmoving down their concentration gradient to actively transportanother solute. Example- proton pump creates a proton gradient, the cotransporter uses this gradient to import sucrose.

Front 15

what are vesicles? What is endocytosis and exocytosis?

Back 15

small sacs of membranes that completely enclose theircontents. They can either bud off existing membranes or fuse with them. Within cells, vesicles have manyfunctions, including transport of contents among various organelles and digesting molecules.
Endo- buddingoff from the cell membrane towards the inside of the cell [to ENCAPTURE]
Exo-fusion of a vesicle with the cell membrane [to RELEASE]

Front 16

What are the three types of endocytosis? Briefly describe each. What are ligands? Example of receptor mediated?

Back 16

Phagocytosis:solids like bacteria, cell eating usually fuse w lysosome
pinocytosis: cell drinking, liquids and veryy small particles, nonspecific
receptor mediated: bring in specific substances determined by receptors on the surface of the membrane. Substances that bind to a receptorare called ligands. LDL cholesterol