membrane structure and function

Question 1

plasma membrane

Answer 1

phospholipid bilayer

contains proteins and sugars attached to lipids and proteins

Question 2

membrane lipid

Answer 2

phosphatidylcholine
phosphatidylethanolamine
phosphatidyl serine
spingolipids (no glycerol)

Question 3

function of phosphatidylcholine

Answer 3

naturally forms bilyae
contains choline
kinked tails for fluidity of membrane

Question 4

phosphatidylethanolamine

Answer 4

inner leaflet
stabilises membrane structure
amine group creates charge and bondnig

Question 5

cholererol

Answer 5

increases fluidity

lipid soluble

Question 6

lipid rafts

Answer 6

formed due to cholesterol moving in membrane
can bring proteins together associated with rafts
regulated function of membrane protiens

Question 7

GPI protiens

Answer 7

joined to membrane by sugar
associated by rafts and brought together
influence signalling and function of proteins in membrane

Question 8

disruption of lipid rafts

Answer 8

alters protein fucntion

alcohol or high cholesterol

Question 9

membrane protiens

Answer 9

transporters
anchors
receptors
enzymes

Question 10

mechanisms of transport

Answer 10

diffusion
facilitated diffusion
gated channels
active transport

Question 11

facilitated diffusion

Answer 11

solute binds to proteins
protein changes conformation
down conc gradient

Question 12

gated channels

Answer 12

proteins form a pore for molecules that cannot diffuse normally
open and close due to signal/stimulus

Question 13

active transport

Answer 13

primary
movement of one moecule up a concentration gradient using ATP
secondary
false electrochemical gradient created by pumping a molecule out
allows molecule to diffuse back in with another molecule (co transport)

Question 14

types of transporters

Answer 14

symport - 2 molecules the same way
uniport - one moecule
antiport - 2 molecules oppositie ways

Question 15

ionophore mediated tranpsort

Answer 15

lipids that are able to pass through membrane encase another molecule

Question 16

anchors

Answer 16

anchor the cell to ECM
integrins common anchors
binds cytoskeleton and ECM

Question 17

receptors

Answer 17

autocrine - same cell
juxta crine - adjacent cell
paracrine - close cells
endocrine - through blood stream, long distance

Question 18

types of membrane bound receptors

Answer 18

ion channel
heptahelical
kinase associated receptors

Question 19

ion channel receptors

Answer 19

associated with protein channel

when ligand binds, receptor changed shape and nudges protein which alters conformation for ions to flow through

Question 20

heptahelial receptors

Answer 20

7 alpha helices through the membrane
binding causes intracellular changes
involves second messenger

Question 21

kinase associated receptor

Answer 21

binding of signal causes phosphorylation intracellularly
2 receptors in membrane, tyrosine inside cell
signal binds, receptors move together
tyrosine becomes phosphorylated
causes further phosphorylation in the cell of protiens
signal reaches nucleus

Question 22

membrane bound enyzymes

Answer 22

can act as receptors
can cleave other proteins
catalyse reactions

Question 23

angiotensin system

Answer 23

ACE in membrane
ANG I in blood stream
enzyme catalyses ANGI to ANGII
can then bind to receptor

Question 24

what is cancer due to

Answer 24

over effect of kinase receptor

Her2 protein receptor can be overproduced, cell divides rapidly