Cell Biology Test 2

Front 1

Charles Overton

Back 1

Confirmed the lipid nature of the cell membrane. - 1895

Front 2

Julius Bernstein

Back 2

1902 - Explained the electrolyte interior of cells and the electrolytic potentials in nerve cells.

Front 3

Irving Langmuir

Back 3

1917 - Discovered that cell membranes are monolayers or bilayers through the use of a Langmuir Trough

Front 4

Gorter and Grendel

Back 4

Used RBCs to extract and measure phospholipids. Under-extracted and undercalculated.

These mistakes cancelled each other out to confirm bilayer.

Front 5

Mudd and Mudd

Back 5

Analyzed blood cells:

White blood cells prefer water medium/RBCs prefer more lipid medium

Front 6

Danielli and Dawson

Back 6

1935- First model of plasma membrane:

Components:

-phospholipids

-proteins

-pores

Front 7

J. D. Robertson

Back 7

1950s

First used TEM to view cell membrane - confirmed the D & D model

Used OsO4 to fix and stain the cells

Front 8

Freeze Fracture

Back 8

TEM technique to produce membrane replica.

Bumps proved to be proteins/pores. Liposome control showed smooth surface

Front 9

Fuse-living cells

Back 9

Cell fusion experiment with antibodies - must be mouse or human receptor specific.

Concludes some integral proteins can move laterally throughout the "fluid" membrane.

Front 10

Cell Patching

Back 10

Add bivalent antibodies to cell. Antibodies will line up -----concludes fluid membrane.

Front 11

Fluid-mosaic model

Back 11

Made by Singer and Nicholson - 1972

1) Integral proteins cannot be washed out and are integrated into the cell membrane

2) Peripheral Proteins can be washed off and sit on the surface of the cell membrane

Front 12

Integral membrane proteins

Back 12

Single pass - cross the membrane only once

Monomer

Multi-pass - weave in and out of the membrane

Barrel protein - usually used for ion transport

Multi-meric - has more than one protein component

Front 13

Glycocalyx

Back 13

Collective carbohydrate groups on the outside of the cell

Con-A labels this

Front 14

Hydropathy plot

Back 14

Used to predict the topology of membrane proteins

Membrane spanning region of very hydrophobic amino acids anchor the proteins with non-covalent bonds

Front 15

Red Blood cells

Back 15

Cell membrane experiment favorites:

-Easy to get and pruify

-No contaminating membrane/organelles

-Easy to make RBC ghosts (lyse with hypotonic)

Front 16

Adherins

Back 16

Purpose: Cell Adhesion

Encircles the cell

Cadherins keep cells together and are Ca2+ dependent; associated with actin cytoskeleton.

Front 17

Demosomes

Back 17

Designed for strength and found in epithelial cells.

Intermediate filaments connect desmosomes.

Front 18

Pemphigus Vulgaris

Back 18

Autoimmune disease that targets key desmosome protein (Desmogelin 3).

"Unzips" the skin and epidermis peels off.

Front 19

Tight Junctions

Back 19

Keeps fluid separated in tissues. Specialized proteins keep fluids out

E.g. bladder, kidney, intestine.

Lanthanum hydroxide/Sodium fluorsein is not membrane soluble and moves up and around cells until tight junction.

Front 20

Gap Junction

Back 20

Passes small molecules like cAMP and ions.

Sometimes electrical junctions

Connexon - actual hole in membrane

Front 21

ATP Pump

Back 21

Uses ATP to pump ions against gradient.

Front 22

Uniporter

Back 22

Pumps one molecule.

Front 23

Symporter

Back 23

Cotransporter system.

Moves two molecules in the same direction:

One from high to low, and the other from low to high.

Front 24

Antiporter

Back 24

2 molecules in the opposite directions against their gradient.

Front 25

Autocrine

Back 25

Ligand is release from cell and received by the same cell receptor.

Cells can become cancerous if self-produces growth hormone.

Front 26

Paracrine

Back 26

Ligand is released from one cell and received by another nearby cell.

Front 27

Endocrine

Back 27

Ligand is released into the blood stream and reacts with target cells all over the body

Front 28

Pheramones

Back 28

Released by one organism and affects another.

Front 29

Lipid Soluble ligands

Back 29

Permeable to the cell membrane and has intracellular receptors

Steroids

Front 30

Lipid insoluble proteins

Back 30

Need extracellular membrane receptor.

Activates second messenger system.

Front 31

Ion channel receptor

Back 31

Very fast acting; ligand binds to receptor and channel is immediately opened.

ex. nicotinic acetlycholine receptor

Front 32

Receptor Mediated Endocytosis

Back 32

Delivers ligand into the cell.

Front 33

Second Messenger Activation

Back 33

Ligand activates secondary messenger system when bound to receptor.

Cytokines, g-coupled receptors

Front 34

G-protein Coupled Receptors

Back 34

Usually interact with

Front 35

Receptor Tyrosine Kinase

Back 35

Exists as separate monomers until activation by ligand.

Relies on autophosphorylation for signal transduction.

Front 36

Forskolin

Back 36

Activates adenylate cyclase and increases intracellular levels of cAMP

Front 37

Smooth Endoplasmic Reticulum

Back 37

Not associated with Protein synthesis; fatty acid and phospholipid syn.

Good for detox (Liver).

High levels of Calcium

Front 38

Rough Endoplasmic Reticulum

Back 38

Protein syn. occurs;

Proteins are glycosolated

Formation of disulfide bonds

Front 39

Where does glycosylation occur?

Back 39

RER

Cis-Golgi

Medial-Golgi

Trans-Golgi

Front 40

Type I Integral Protein Synthesis

Back 40

Requires an internal signal anchor sequence.

Cleaved N-terminal signal sequence.

C-out, N-in

Hydrophobic domain in the middle.

Contain stop-transfer anchor sequence.

Front 41

Type II Integral Protein Synthesis

Back 41

No signal sequence is cleaved from the N-terminus

C-in, N-out

hydrophobic domain in the middle

Contain signal -anchor sequence

Front 42

Type III Integral Protein Synthesis

Back 42

No signal sequence is cleaved.

C-out, N-in

Hydrophobic tail at N-terminus

Contain signal -anchor sequence

Front 43

Tail Anchored

Back 43

C-in, N-out

Hydrophobic anchor at C-terminus

Front 44

Type IV

Back 44

Multiple hydrophobic domains.

G-coupled proteins are an example

Front 45

Protein Disulfide isomerase (PDI)

Back 45

Oxidizes proteins with thiol groups to form disulfide bonds.

Especially abundant in the ER of liver and kidney.

Can also rearrange disulfide bonds so proteins fold correctly.

Front 46

Ras G-protein

Back 46

Signaling molecule within cells involved in activation pathways for cell growth, proliferation and survival.

Over activation leads to cancer.

Front 47

BiP

Back 47

Molecular chaperone in the lumen of the ER.

Maintains proteins in unfolded state until ready for folding.

Prevents protein from backsliding through the translocon.

Front 48

Patch Clamp

Back 48

Allows the ability to measure the electropotential of a single or multiple ion channel.

Front 49

Regulated Secretory Pathway

Back 49

Can store proteins in large electron-dense vesicles.

Dependent on Ca2+ or hormones for release

Release lot of proteins at once

Front 50

Constitutive Pathway

Back 50

used for integral membrane proteins. Proteins are not store and released immediately.

Ex. proteins that are synthesized all the time like collagen

Front 51

Muscarinic acetlycholine receptor

Back 51

`

Front 52

HSP Complex

Back 52

Produced by cells in exposure to stressful conditions such as heat/cold.

Binds to the steroid receptor; often found in the cytoplasm; inhibitory in nature.

Front 53

Cholera Toxin

Back 53

Blocks GTP hydrolysis

Front 54

Earl Sutherland

Back 54

Discovered the cAMP secondary messengers pathway.

Front 55

KDEL Peptide

Back 55

Receptor that prevents protein from being excreted from the RER

Front 56

The Unfolded Protein Response (UPR)

Back 56

Activated in a response to accumulated unfolded or misfolded proteins.

Front 57

Brefeldin A

Back 57

Can induce the UPR.

Inhibits transport from the RER to the Golgi

Front 58

Familial hypercholesterolemia

Back 58

Class I - LDL Receptor not synthesized

Class II - LDL receptor not properly transported to the cell surface

Class III - LDL receptor does not bind to LDL

Class IV - LDL does not properly cluster in endocytosis

Class V - LDL receptor not recycled

Front 59

Glycophorin

Back 59

Highly glycosolated protein on the outside of red blood cells which gives them very hydrophilic coat preventing them from sticking to vessels.