Lecture 14: Membranes I

Question 0

Major driving forces of assembly of lipid bilayer?

Answer 0

Hydrophobic interactions (major)
van der Waals-attractive forces b/w hydrocarbon tails
Electrostatic & Hydrogen-bonding-attraction b/w polar head groups and water molecules

Question 1

What are the 3 significant consequences of hydrophobic interactions?

Answer 1

Bilayers have inherent tendency to be extensive
Bilayers close on themselves so no exposed hydrocarbon chains
Bilayers are self-sealing b/c hole is energetically unfavorable

Question 2

T/F: Lipid bilayer is highly permeable to polar molecules

Answer 2

False, bilayer has low permeability for ions and polar molecules

Question 3

Where does oxidative phosphorylation occur?

Answer 3

Inner-mitochondrial membrane

Question 4

Where does the TCA cycle & fatty acid oxidation take place?

Answer 4

Mitochondrial matrix

Question 5

T/F: Alpha-helix is most membrane spanning structure.

Answer 5

True

Question 6

What are the 3 types of lipid-linked protein modifications?

Answer 6

Palmitoylation- cysteine residues
Farnesylation- cysteine residues
Glycosylphosphatidylinositol-link (GPI)

Question 7

Why do mitochondria have specialized membranes?

Answer 7

They have a permeable outer membrane and impermeable inner membrane (matrix)

Question 8

What is mitochondrial fission?

Answer 8

Separation of one mitochondria into two new mitochondria

Question 9

What is mitochondrial fusion?

Answer 9

A healthy mitochondria gobbling up unhealthy mitochondria=mitophagy

Question 10

T/F: ATP is required to transport a protein across the inner membrane into the matrix

Answer 10

True