M2 Membranas Flashcards
which organism’s membrane does not contain a bi-layer?
Archea
composition of sphingosine?
Ceramide, lipid, choline and PO4
22: 4 /_\ 8 ω-9 is the nomenclature for a fatty acid. What does each part mean?
22- number of carbon atoms
4- number of double bonds
/_\ 8 - position of double bond
ω-9 - position of the last double bond until the end of the chain.
what are proteins which are covalently bound to lipids called(em portugues)
proteinas ancorradas a lipidos
which of these ions are more inside the cell than outside?
k+, nA+, mG2+, h+, Cl-
K+
which ions have more extracellular concentration?
Na+, H+, Mg 2+, Ca2+
arrange these in order of increasing permeability to the cell
Glycerol,urea, H20, O2, steroid hormones, Na+, glucose,sucrose, H+, Cl-
Na+,H+,Cl-,— Glucose,sucrose—H2O, Urea, glycerol—O2, steroid hormones
what kind of molecules ais the membrane impermeable to? why?
ions because they have a high degree of hydration due to the charge
What favours the permeablility of the lipid bilayer?
The smaller the molecule and the more hydrophobic or nonpolar makes it more permeable
what is the difference between symporters and antiporters?
symporters take energy gotten from molecules going down their gradient to transport molecules against their gradient, both are going in the same direction
while
Antiporters take energy from molecules going against their gradient to transport molecules against their gradient, but both are going in different directions
what is the driving force that help active transporters take molecules against their conc gradient?
electrochemical gradient: the combination of the conc gradient of the molecule( the average between where it is high and where it is low) and the membrane potential energy (readiness of the membrane to put the molecules in equal charge so it can be stable)
what are co-transporters?
Secondary active transporters: Symporter and Antiporter
how does the glucose-Na+ symporter work?
It uses Na+ going down it’s concentration gradient, passively, establishing and electrochemical gradient to give energy to transport glucose against it’s gradient, but in the same direction as Na+
what is the name of the symporter that transports glucose with energy from Na+?
GLUT1
which types of membrane proteins are specific and saturated?
Co-transporters
For active transport, the energy that it needs can only come from ATP, chemical energy
True or false, and why
False, because this type of transport is in plants, where they get solar energy and their specific ATPases use them for transport
What are the types of ATP driven pumps?
P, ABC, V, F (pavaf)
how do the types of atpases work?
When there is high ATP/ADP ratio, it hydrolyzes ATP to give energy which help transport substrates,
When there is low ATP/ADP ratio, it synthesizes ATP
what is the type of ATPase found in mitochondria and chloroplasts?
F-type ATPase; produces ATP energy in them
what do you think the sodium-potassium pump takes molecules?
Down or against their gradient?
Both sodium and potassium against their gradients
how does the Sodium-potassium pump impact on the membrane potential?
The N-K pump pumps 3 sodium ions out of the cell and lets in 2 potassium ions.
And knowing that potassium has a high concentration inside the cell and sodium has a high conc outside the cell, doing this maintains the membrane potential energy, or charge by keeping the positiveness of each atom which may have been disrupted by other transporters equal
where does glucose have a high concentration?
inside the cell
The Sodium-potassium pump acts as a stabilizer of membrane potential destablized by the action of what transporter?
GLUT1 (symporter of glucose)
when glucose is symported into the cell, how is it exported out (in the case of need in the blood
Through a uniporter taking it passively (from high to low) to the extracellular fluid
which type of pump consumes a lot of energy in the cell?
Sodium-Potassium pump
In vertebrates, ann ABC transporter can be found where?
Endoplasmic reticulum
Aquaporins are permeable to water and ions. True or false
False. They are permeable to water but impermeable to ions
In most animal cells, why is osmosis not used much in regulating the volume of a cell?
Because most of the cytoplasm is not in watery state but gel like state
Why can’t aquaporins conduct ions?
They contain hydrophobic amino acids on the other side of the pore which makes it impermeable to ions
which type of membrane protein have very fast transport and are not saturated
Ion channels
A abertura dos canais é regulada em
resposta a estímulos, que podem ser eléctricos, mecânicos ou ligandos
Verdade ou falso
Verdade
Os canais de ioes sao nao seletivo
Verdade ou falso?
falso
Sao altamente seletivo
how does action potential work?
Normally, without the presence of voltage gated channels, there will be no action potentials, this is because by having specific voltages which enable them open or close, they are able to stretch the signal across longer distances
