Cell Membrane Flashcards
These membrane proteins are represented by proteins that a hydrophobic domain and two hydrophilic domains
Transmembrane proteins
The structure of biological membranes can best be described as?…
fluid mosaic of proteins interspersed in a phospholipid bilayer
Located within the bilayer, it moderates membrane fluidity by restricting movement of phospholipid fatty acid side chains at high temperatures
Cholesterol
This membrane transport molecule carries two molecules simultaneously or sequentially in opposite directions
Antiporters
In 1972, what did S.J. Singer and G. Nicholson propose?
The fluid mosaic model
What are the fatty acid characteristics that influence fluidity?
Double bonds- inhibit axial rotation and induce kinks
Long chain fatty acids pack well together and limit movement while short fatty acids create spaces into which other chains can move.
Phospholipid bilayer is split into two leaflets- outer and inner. What’s in the outer layer?
Cholesterol, phosphatidylcholine, and sphingomyelin, glycolipids, glycocalyx
Inner leaflet?
Cholesterol, phosphatidylethanolamine, phosphatidylserine (-charged), phosphatidylinositol (-charged, found only in inner leaflet, important in cell signaling)
How can peripheral proteins be removed from the phospholipid bilayer?
By altering the pH or ionic content of the environment
How are integral proteins removed?
Detergents like SDS.
T/F membrane spanning portions of transmembrane proteins are usually alpha helices with 20-25 hydrophilic amino acids.
False, they are hydrophobic Amino acids
Band 3 is an example of a transmembrane protein, the anion transporter for which ions?
Bicarbonate and chloride ions
Enzyme linked receptors (receptor tyrosine kinase) and glycophorin (RBC membrane) are examples of?…
Single pass transmembrane proteins- single hydrophobic domain that passes through the bilipid layer only once
Multiple pass transmembrane proteins has two or more hydrophobic domains which molecules can pass several times. How are they activated?
Addition of phosphate
GLUT- glucose transporter (12)
Porin(12)
G protein linked receptors(7)
Various large transporter and channel proteins
Are examples of what?
Multiple pass transmembrane proteins
What are the six types of proteins found in/on the cell membrane?
Channels, pumps, transporters, enzymes, receptors, structural proteins associated with tight junctions
What are the types of movement mechanisms?
Diffusion, osmosis, facilitated diffusion, active transport.
Carries two or more molecules or ions simultaneously or sequentially in the same direction
Symporter
Carries one molecule or ion unidirectionally
Uniporter
Ex: use in facilitated diffusion
Two types of channel complexes
Non gated and gated
Responds to specific signal molecules like hormones or neurotransmitters.
Ligand gated channel
Responds to change in electrical potential across the membrane.
Voltage gated channel
Responds to physical change in the environment such as pressure or touch.
Modality gated channel
Glycolysis is this type of respiration? Where does it occur? What does it produce?
Anaerobic-does not require oxygen
Occurs in the cytoplasm of all cells
Produces pyruvic acid (lactic) and 2 ATP
Krebs cycle and ETC (electron transport chain) is this type of respiration? Occurs where? Produces?
Aerobic respiration
Occurs only in the mitochondria
Utilizes pyruvic acid from glycolysis, requires oxygen as the final electron receptor, produces CO2 and H2O and 34 ATP+ 2 from glycolysis=36ATP
What are the three factors that affect diffusion?
Concentration differences, electrical differences, and pressure differences
What’s V max to facilitated diffusion?
The rate of diffusion slows down and plateau’s when it reaches a maximum concentration of molecules diffusing in a given period.
Potassium channels with selectivity filters and carbonyl oxygens are a type of this channel?
Non gated
What are the two types of active transport?
Primary and secondary
Primary active transport utilizes these transporters and derives its energy from?
ATPase transporter
Energy is directly derived from breakdown of ATP
Secondary utilizes these transporters and derives energy from?
Multiporters (sym and anti)
Energy derived from concentration differences of ions/molecules created in primary
Which ion is most often one of the solutes involved in secondary AT.
Sodium
If sodium moves down its gradient then why is this secondary active transport?
Note: active transport moves a molecule UP (against) it’s gradient
Because the movement of sodium into the cell (down gradient) generates enough energy needed to transport another substance against (up) its gradient with the use of ATP.
Sodium/calcium antiporters move three sodium ions per one calcium ion. Why?
Because calcium is larger and has more charge
