lecture 6 Flashcards
1
Q
A
2
Q
phagocytosis
A
- e.g. macrophages engulfing large bactiera
3
Q
pinocytosis
A
- small invaginations that take in liquid, non selective
4
Q
how do cells internalize ec materials
A
phago, pino, receptor mediated
5
Q
LDL
A
- important for maintaining cholesterol levels which are important for membrane structure
6
Q
amphipathic shell
A
- phospholipid monolayer and apolipoprotein
7
Q
apolar core
A
hydrophobic, mostly cholesteryl esters
8
Q
what is LDL made up of
A
- 88% cholesterol ester and mediates cholesterol transport
9
Q
lipoproteins
A
- transport lipids in large, well-defined water-soluble complexes called lipoproteins
10
Q
at what pH does the ligand binding arm lose affinity for the ApoB
A
5-5.5
11
Q
acidification of endosomes and lysosomes
A
- V-class proton pumps are used to transport H+ across membranes through an ATP dependent mechanism
- Cl channels are on lysosomal and endosomal membranes
- the pumped protons are passively followed by chloride ions
- this leads to acifidcation of the lumen through the creation of HCl
12
Q
familial hypercholesterolemia
A
- caused by LDLR mutations
e.g. not having an LDL receptor, having a receptor that binds LDL poorly, the receptor cannot internalize LDL - this can lead to the accumulation of cholesterol, which creates bulges and which can acclimate in the lumen of arteries, leading to heart attacks or strokes.
13
Q
autophagy
A
- important to get rid of problematic materials by degrading problematic proteins, lipids, organelles
- lysosomal/vacuolar degradative pathway conserved in euks
- can cause long lived proteins to form aggregates if this process was not presnt
- worn out peroxisomes or mitochondiral accumalation can form ROS and other toxic species
14
Q
receptor mediated endocytosis
A
- method of selective internalization of specific EC molecules (ligands)
- e.g. LDL, transferring, hormones
15
Q
Autophagosome
A
Double membrane vesicle that fuses with lysosomes
