binghamton university bio exam 2 bio 311

Langmuir Trough

-used an experiment w/ pressure and proposed that a cell membrane could be a phospholipid bilayer (as opposed to monolayer)

-1917

Danielle and Davson

first formal model of a cell membrane

-1935

-protein-phospholipid-protein sandwich with a polar pore lined w/ proteins

what is the significance of the J.D. Robertson model?

-used TEM

-confirmed D/D model

-found OsO4 on the membrane

-suggested glycosylation

1960's/1970's 4 critical experiments...what were they?

1) Freeze fracture- Dan Branton

2) Cell fusion

3) Cell patching/capping

4) FRAP

Freeze fracture by Dan Branton

-he was the 1st developer of FF

-they used a RBC and FFed it and found mosaic of bumps

-discovered transmembrane proteins

fluid mosaic model

A model that describes the structure of cell membranes. In this model, a flexible layer made of lipid molecules is interspersed with large protein molecules that act as channels through which other molecules enter and leave the cell.

FRAP using con a

binds to carb groups

50% of proteins migrated

endoplasmic vs cytoplasmic

endo cytoplasmic

outside inside

glycosylated non glycosylated

RBC ghost

inside out rbc

why are RBC's the best cell type

plentiful

easy target

easy to seperate

membranes are simple

spectrin

rbc dimer

binds to glycophorin

cytoskeleton proteins that line the intercellular part of the cell membrane.

fibrous tetramers

ankyrin

binds to spectrin

asymetric distribution of phospholipids is apparent because?

outer and inner leaflets (lipid bilayers)

phosphoglycerides

cytoplasmic leaflet

in cancer it's an endoplasmic leaflet

3 types of phospholipids

phosphoglycerides, sphingolipids, cholesterol

flippase

transmembrane lipid transporter fluorochromes

quenchers

enzyme that flips phospholipids from exoplasmic faces

sphingolipid/sphingomyelin

main component of myelin

sterols

steoid alchohols

3 kinds of plasma membrane proteins

integral membrane proteins, lipid anchored proteins, peripheral proteins

integral membrane proteins

permanently attached to the biological membrane

not easily washed off

lipid anchored protein

A type of integral membrane protein that is attached to the membrane via a lipid molecule.

can wash off

anchored to lipids

peripheral proteins

Protein appendages loosely bound to the surface of the membrane and not embedded in the lipid bilayer.

easily washed off

bacteriorhodopsin

integral membrane protein

transports protons across cytoplasmic membrane

serpentine

800 diff types

4% of proteins

-signaling

CPR family

G protein coupled receptors

G protein coupled receptors

A signal receptor protein in the plasma membrane that responds to the binding of a signaling molecule by activating a G protein. indirectly activate protein kinase enzymes

glycophorin

rbc

carries sugar molecules, heavily glycosylated

integral mem prot

single pass dimer

trans mem domain has hydrophobic AR

hydrophillic charged coat

receptor mediated endocytosis

receptor-ligand interaction. Receptors on the plasma membrane of the target tissue will specifically bind to ligands on the outside of the cell.

LDL

low density lipoprotein (carries cholesterol)

ligand

A molecule that binds specifically to another molecule, usually a larger one.

coated pits

regions of the cell membrane specialized in receptor-mediated endocytosis.

ldl is relased at ph of?

idk but it's acidic

founder effect class I

LDL-R isn't synthesized

transport defect

LDL isn't properly transported

binding defects

LDL is not properly bonded

founder effect class IV

LDL doesn't cluster properly

recycling defect

LDL does not properly recycled

adherens junction

a cell junction whose cytoplasmic face is linked to the actin cytoskeleton. Protein complexes that occur at cell-cell junctions in epithelial and endothelial tissues, usually more basal than tight junctions

desmosomes

a structure by which two adjacent cells are attached, formed from protein plaques in the cell membranes linked by filaments.

steroid hormone receptors

internal receptor that turns on specific genes when it is activated by binding a signal molecule. found in the nucleus, cytosol, and plasma membrane of target cells.

ferrotransferrin system

controls the level of free iron (Fe), augments iron update

receptor tyrosine kinase(RTK) mutations and general amount of rtks

100

most are linked to cell division (mutation can = cancer)

receptor tyrosine kinase(RTK)

high-affinity cell surface receptors for many polypeptide growth factors, cytokines, and hormones.

IP3 triggers the release of

intracellular calcium

IP3/DAG

2nd Messenger

Smooth muscle contraction by horm/NT

GnRH, Oxytocin, ADH (V1-receptor), TRH,

Histamine (H1-receptor), Angiotensin II,

Gastrin

patch clamp

technique in electrophysiology used to study ionic currents in individual isolated living cells

insulin

first prot to be chemically synthesized

-binds to receptor(glucose enters cell)

-protein synthesis

-differentiation(stores fat)

cAMP system

effector?

adenylate

studying the cAMP system:

Forskolin

supplement

binds and activates adenylate and increases [cAMP]

studying the cAMP system:

Cholera toxin

gtp cant become gdp

dehydration

studying the cAMP system:

GMP-PNP

non-hydrolyzable and keeps the G-protein. The GPCR system always sees GMP-PNP as GTP

methy xanthides and cAMP

inhibits cAMP frombecoming AMP

cAMP

second messenger

cell specific interactions

activates protein kinase

-in cyto=activation of PKA

RTKs

dimer

stimulates cell division using g proteins

what is transported by

transferrin receptor mediated endocytosis

iron

how does cAMP work in the nucleus

translocation of catalytic unit to nucleus

GPCR

900

receptors

-use g proteins

-1 mono metric g prot

-3 tri metric g prot(most used)(3 steps)

CHO cells

- used to measure glucose transport

db cAMP

membrane solulable analog of cAMP

calcium

used for muscle contraction,action potentials,cell-cell adhesion

ca2+ binds to calmodulin

glutamate causes neurons to increase [Ca2+]

-that can cause seisers if too much

calmodulin

inhibits kinase

can cause cell death

Nitricoxide(NO)

gas

diffuses out of cells to affect adjacent cells

-used for blood pressure (increase[NO]=decrease in blood pressure cuz blood vessels dilate)

protein destinatinos

export

dissolved in cytoplasm

embeded in cell memrane

go to an organelle

keith porter

discovered smooth and rough ER

smooth ER

Ca2+ resivuor

site of fattyacid/phospholipid synthesis

cytoskeleton

detoxification

transport

differentiate proteins

RER post translational translocation

-prot with signal recognition particle attaches

-protein synthesis recommences

-signal sequence is cleaved

-protein goes to the lumen

where are most multimuric proteins assembled?

RER

what RER proteins are critical to assembly?

PD!

BiP(chaperone)

calneticulin

endoplasmic reticulum can check protein validity

how do RER vesicles find their target?

Vsnare and Tsnare