Ch. 10 review: Lipids

• Working with lipids:– Analysis of lipid content of a tissue:

1. ‘Dissolve’ tissue components in a mixture of chloroform, methanol, and water

2. Add water--solution separates into two phases: aqueous/methanol and organic• What is in each phase?

3. Use chromatography to separate lipids of different polarity– Name two characteristics of lipids that influence polarity

• Which of the following pairs of lipids would have the highest melting point? – (a) stearic acid (18:0) or (b) oleic acid (18:1)

– Oleic acid: omega-9 fatty acid (olive oil)

– (a) palmitoleic acid (16:1) or (b) oleic acid (18:1)– (a) phosphatidylinositol or (b) triacylglycerol

Why the aliphatic chain?

Ch. 10.7• When the hormone vasopressin stimulates

cleavage of phosphatidylinositol 4,5-bisphosphate by hormone-sensitive phospholipase C, two products are formed. What are they? Solubility?

Chapter 11 (Membranes)

• Fluid “Mosaic” model:– List components of biological membranes

Peripheral vs. Integral Membrane Proteins

• Characteristics

• Purpose

• Peripheral membrane proteins: often transiently associated with the membrane– on/off in regulated manner

Lipid fluidity

• How is it an advantage?

• Why does it need to be restricted?

Membrane fusion• Why is it so difficult?

– Vesicles have to fuse with the plasma membrane at the right place/time

– Physically: mixing of polar headgroups and hydrophobic regions

• “Unstable void space” figure 11-25

Solute transport across membranes

• Simple diffusion

• Facilitated diffusion (a.k.a. passive transport)

• Active transport– Primary (chemical energy input (ATP))– Secondary

Facilitated diffusion~catalysis

“Side” note: Primary active transporters (pumps)

P-type ATPases: Ion pumps (metals Na+,K+,Ca2+, etc)F-type, V-type ATPases: Proton pumps (H+)

-pH regulation, ATP synthesis

Chapter 13: bioenergetics(problem 18)

Oxidizing agent + n electrons → reducing agent

The E'° values for NAD+/NADH and pyruvate/lactate redox pairs are -0.32 V and -0.19 V, respectively(a) What are the oxidizing/reducing agents in the redox pairs?(b) Which chemical has the greatest tendency to lose electrons?(c) Which is the strongest oxidizing agent? (d) Under standard conditions, in which direction will the following reaction proceed?

Pyruvate + NADH + H+ ↔ lactate + NAD+