1.)Compartmentalization- allows specialized activities to proceed without external interference and allows cellular activities to be regulated independently of one another.

2.)Scaffold for biochemical activities- framework.

3.)Selectively permeable barrier for transport and communication.

4.)Transporting solutes- establish ionic gradients

5.)Responding to external signals-  Signal transduction.  6.)Membrane receptors combine with specific ligands to activate cell. 

7.)Intercellular interaction-

8.)Energy transduction 

CAN: Small hydrophobic molecules (O2, CO2, N2,benzene),small uncharged polar molecules (h20, glycerol,ethanol)

CANNOT: Large uncharged polar molecules (AA, glucose, nucleoside), Ions: H+, NA+, HCO3-, K+, Ca+ Cl-, Mg2+

GTP and G proteins

known as..
involved in what(4)..
mediated by what ..

widely used for energy transferring triphosphate
nexted to ATP. Involved in protein synthesis, budding, fusing of membrane vesicles, and the transmission of signals received by the cell surface.

GTP action is mediated by a speical class of GTP-binding protein called G-proten

Hydrolase

5 examples

formula

catalyze hydrolytic cleaveage reactions. Splits H20

Esterases, amidases, glycosidases, peptidases, phosphatases.  

AB + H2O -> AH + BOH

synthesize molecules in anabolic reactions by condensing two molecules together

ADP+ Pi-> ATP

adds a phosphate to ATP

Isomerase

4 examples

involve in what

formula

catalyzes the rearrangement of bonds within a single molecule

Isomerase, racemase, epimerase, mutases. 

These are involved in intramolecular rearrangements.  

  X-C-OH   -> X-C-O-P

      C-O-P       C-OH

Catalyzes polymerzation reactions such as the synthesis of DNA and RNA

puts together nucleotides

DNA polymerase->DNA 

RNA polymerase -> RNA

Catalyzes the hydrolytic removal of a phosphate group from a molecules

takes ATP ->ADP or Pi ->(CK)-> Creatine phosphate

Oxido-reductase

carry out what?

Formula

one molecule is oxidized while the other is reduced. this is often called oxidases, reductases, or dehydrogenase

carry out redox reactions

Ligases

what does it do?

formula

These join two molecules coupled to the cleavage of a high-energy bond. 

X+Y+ATP ->XY+ADP+Pi

-Who discovered RNA moelcules capable of acting as biological catalyst

-what is the RNA based catalysts

-another example of robozyme

-Thomas R. Cech

-it was a robosomal RNA molecule of the protozoan tetrahymena. rRNA has teh ability to self-splice

Ribonuclease P. which speeds a reaction in which a surplus segment is removed from a tRNA

signal transduction

example

Respond to external signals

smell: olfactory

Cholesterol does what 3

it is absent from membranes of

what does it do?

adds ridgity to the membrane, broadens the range of biological acitvity, increases the stability and flexibility of a membrane, assemtry of the cell membrane phospholipids

most plants and all bacterial cells

hydrophobic rings interfere with the movement of the fatty acid tails of the phosphlipids. They play a major role in membrane fluidity.

what are three tyes of membrane lipids in cell membrane?

they are all what?

1.   Phosphoglycerides

2.   Sphingolipids

3.   Cholesterol

amphipathic 

Lipid Bilayer fluid mosaid model
unsaturated means its..

tails are_____
Heads are_____

Head contains 3 .. 

unsaturated means its kinked and fluidity

tails are hydrophobic

heads are hydrophilic

choline, phosphate, glycerol

Phosphoglycerides

general characteristics

4 ..

membrane glycerides are diglycerides

most common groups linked to phosphate head : choline= phosphotidylcholine (PC), Ethanolamine = phosphatidylethanolamine (PE), serine= phosphatidylserine (PS), inositol= phosphatidylinositol (PI)

-Animal glycolipid is called a 

-consist of a what

-^ is what

-3 examples

sphingolipid:

primary animal glycolipid consist of a sphingosine linked to a fatty acid;

which is an amino alcohol with a long hydrocarbon chain.

examples: glycolipids, cerebroside, gangliosides

nervous system contains high concentrations of glycolipids : Myelin sheath

Importance of Glycolipids in 3 diseases

caused by entering.. 

Sphingolyelin is a _______

Cerebrosides and Gangliosides are ____

phospholipids

glycolipids

Glycosphingolipids identified..

implicated in what..?

What is a deficiency in metabolism of this

*Have identified as sites of recognition by antibodies in immune reactions and as a antigen responsible for blood groupings.

*Implicated in binding sites for peptide hormones and the cholera and tetnus toxin

*Taysachs: build up and accumulation as a result in interfering with berve and brain functioning (in lysosomes) -> paralysis and mental impairment

Sterol are in  _____ & _____

fungi is called a ______
what is the predominate sterol of animal membranes

sterol in bacteria is limited in..?

_____ plays a small quanity in plants

2 antibiotics 

 

*plants and animals
*ergosterol 

*cholesterol

*mycoplasmas

*phytosterol

* amphotencin B and Itracanazole

membrane carbohydrates

3

1.) 90% are linked to membrane proteins to form glycoproteins

2.) short oligosaccharides compare to starch glycogen and cellulose

3.) glycoproteins of plasma membrane are outside, those on the vesicular membrane are internal away from cytosol

nature and importance of the lipid bi-layer

form what and does what

what is it known as ""

lipid composition can determined physical structure of the membrane and activity of membrane proteins

can form a spherical vesicle called Liposomes which are being tested as vehicles to deliver drugs or DNA molecules within the body "stealth liposomes"

Name three types of things derived from cholesterol?

Where is cholesterol made?

if you eat Saturated fat it does what?

causes what 

testoterone, estradiol, cortisol

in the liver

increase cholesterol production

atherosclerosis: heart disease because coronary artiers are at high pressure which makes the elastic artiers stiffen = break

 a. mediating the interactions of a cell with its environment

b. Sorting of membrane proteins to different cellular compartments

c. Blood typing

plays a major role in glucose metabolism

if stress: hard time burning energy because conserved energy

tells specificty of immune system 

O- universal donor works for AB
AB can't donate because AB don't have antibodies which binds to antigens 

Integral protein (membrane protein) are 

genome

integral proteins; transmembrane proteins

some one membrane spanning, some multispanning

sequencing studies suggest that integral membrane proteins constitute about 30% of all encoded proteins

Integral membrane protein

detergents 2

why?

________  is difficult

Integral membrane proteins are solubilized in detergents and purified. 

SDS and Triton X-100

hydrophobic interior

X-ray crystallography of integral protein

Lipid Anchored Membrane proteins known as..

define that^

3 total things to remember

Phospholipids with saturated chains pack
together more tightly than those containing unsaturated chains.  The greater the degree of unsaturation of the fatty acids of the bilayer,  the lower the temperature before the bilayer gels.

Length of the chain

the shorter the fatty acid chain of a phospholipid the ____ ___

what does colesterol disrupt

lower its melting temperature

Cholesterol disrupts the close packing of fatty acyl chains and interfere with their mobility.  Cholesterol tends to abolish sharp transition temperatures and creates a condition of intermediate fluidity.  Cholesterol increases durability while decreasing the permeability.

 phase to  solid;  gel phase to liquid.

Activity of certain phospholipids

PI and PS

PI plays a major role in transferring stimuli to the cytoplasm. E.g. muscle contraction

cholesterol and sphingolipids tend to pack together tightly to form microdomains that are more pleated and highly ordered than surrounding regions.   Amyloid precursor protein and gamma secretase (Alzheimer’s) are thought to reside in these

Rafts.  Lower cholesterol diets lower incidence of Alzheimer’s.  

The Dynamic Nature of the Plasma Membrane

What movement is much faster?

Flippase

transversed diffusion

Lateral movement  10 -6 sec is much faster than vertical movement from one layer to the other.  

established symmetry

10^5 sec

Flippases

define..

what role do they play.?

membrane assembles where/begains where?

enzyme inserted where

How do they grow evenly?  

*begins in the ER and the building of the phospholipid membrane

*Enzymes inserted on the cytosolic  side of membrane use free fatty acids to deposit the newly made phopholipids exclusively in the cytosolic half of the bilayer.  

*Scamblases shuffle them to the opposing side.  Other enzymes are also involved. 

Do we have unlimited mobility of membrane proteins?

what are the 4 restrictions on proteins and lipid mobility?

no

1.) some membrane protein moves randomly throughout membrane, rates that are less than would be measured in a artificial lipid bilayer

2.)those who fail to move are immobilized

3.)some protein species are found to move in ahighly directed manner towards one part of cell or another

4.) largest fraction of protein species exhibit random (brownian) movement within membrane, but only able to move few tenths of a micron.

lipid mobility- what do phospholipids do?

how are the fences constructed?

regulation of nutrients and water intake

regualted secretion

protection

cell contact and adhesion

cell communication

cell-substratum contact

generation of ion gradients

sperm cell is covered by what

consist of 

what is another example of a plasma membrane structure?

*one continuous plasma membrane which consist of a mosaic of different types of localized domains

*RBC

SDS-PAGE polyacrylamide gell electrophoresis (2)

spectrin-

what tells muscles to contract?

1.)used to fractionate the proteins of the RBC membrane

2.)separates base on saze and charge

*gives us its unique shape muscular distrophy

*tropomyosin

What is the most abundant integral protein pair of a RBC? 

What does Band 3 serves/ known as

what does most CO2 carried by?

*carbohydrate-containing, membrane –spanning proteins, called band 3 and glycophorin A. 

serves as a channel for the passive exchange ofo anions across membrane : Chloride shift/ *which is known as antiport: shuttles Cl- in and shuttles HCO3- out

*carried by bicarbonates in the plasma

Integral proteins of RBC membrane:

Glycophorin A react when and do what, how is it determined??

      due to the high number of negative charges on sialic acid, is thought to aid in RBCs repelling each other.  Differences in Glycophrin amino acid sequence determine whether a person is MM, MN, or NN.

Peripheral Proteins are located where?

play a major role in what?

Hemolyti anemias
Distrophin is what and results in what? 

highly impermeable to ions such as Na+, K+, Ca++, and Cl-.  Yet the movement of these ions and others is critical to cell function. 

•Ions channels were proposed as early as 1955 by Hodgkin and Keynes. 

Selective permeable: able to separate out like cell membrane K+  20x more selective in regards to Na+

Semi permeable: cell wall

osmosis

how to measure osmolality:

movement of H20 througha semiperimeable membrane from high to low concentrations (like dialysis tubing)

increase solute concentration= decreases Freezing Point

how does water flow?

hemolysis

water flows to higher concentrations

makes RBC creatinated= dehydration

RBC pops

K+ levels rise in guard cells when stomates open and K+ decrease when stomates close.  

Passive transporters move a solute along its electrochemical gradient

name 2 kinds and what they do

Why do those with Diabetes mellitis have excess glucose in their urine?

GLUT2

what kind of transporter and does what

seen where (5) places

what/how it transports

GLUT3

expressed where

*GLUT4

found in where (2)

what its know ask and responsible for

The Na+ pump in animal cells uses energy supplied by ATP to expel Na+ and bring in K+.

accounts for what?

known as the what
ouabin is what

What does the Ca 2+ fo

an influx of Ca2+ in the cytosol i sused by different cells as a what

• keep the cytosolic Ca2+ concentration low
• used by different cells as an intracellular signal to trigger various cell process, such as muscle contraction, fertilization, and nerve cell communication. 

Ion channels are ion-selective and gated

2 reasons why