1. This is a continuation of Problem Set 9, Question 1. Here, you are asked to do an energetic yield analysis for the complete oxidation of Palmitic Acid as an example of a saturated fatty acid. As in the previous problem, assume a P/O ratio of 2.5 for NADH (i.e. 2.5 ATP's per NADH oxidized in oxidative phosphorylation).
a. Complete the table for the complete β-oxidation of Palmitic acid (16:0) to CO2 and HOH:
Substrate level
NADH FADH2 Phosphorylations
Metabolic Stage yield yield (cost or yield)
CoA activation : ______ ______ ______
β-oxidation ( ____ cycles) : ______ ______ ______
TCA ( ____ cycles) : ______ ______ ______
Sub-Total : ______ ______ ______
Summary
Oxidative Phosphorylation :
_____ NADH ? _2.5_ ATP = _____ ATP
_____ FADH2 ? _1.5_ ATP = _____ ATP
Substrate level Phosphorylation : _____ ATP
Grand Total _____ ATP
b. Complete a similar calculation for the complete oxidation of Palmitoleic acid (16:1) to CO2 and HOH. Make any adjustments to the table as required.
2. A bacterium is in the process of acclimating to a higher temperature environment. How would you expect the fatty acid complement (types and relative amounts of fatty acids) in the bacterial membrane to change in response to the higher temperature? Why?
3. What is the energetic price, in terms of ATP equivalents, of breaking down myristic acid (C14:0) to acetyl~CoA and then resynthesizing it?
4. Below is a list of seven 2 carbon compounds (except CO2 which was doubled to make 2 carbons). Arrange these compounds in order of increasing oxidation level (i.e. from most reduced to most oxidized).
CH3COH HOOC-COOH CH3COOH 2 CO2
CH2=CH2 CH3-CH3 CH3CH2OH Due: 25 April 2016
5. Phospholipid lateral motion in a membrane is characterized by a diffusion coefficient (D) of about 1?10-8 cm2/sec. The distance (r) traveled in two dimensions (over the surface of (or in the plane of) the membrane) in a period of time (t) is given by r = (4Dt) ½, where r is the distance traveled in cm, D is the diffusion coefficient, and t is the time in seconds during which diffusion occurs.
a. Calculate the distance traveled by a phospholipid across a bilayer in 10 milliseconds (ms).
Protein lateral motion is much slower than that of lipids because proteins are much larger than lipids. Also, some membrane proteins can diffuse freely through a membrane, while others are bound or anchored to other structures in the membrane. The diffusion coefficient for the
membrane protein fibronectin is approximately 0.7?10-12 cm2/sec, whereas that for rhodopsin is about 3?10-9 cm2/sec.
b. Calculate the distance traveled by each of these proteins in 10 ms.
c. What can you surmise about the interaction between these proteins and other membrane or cytoskeletal components?
d. Sketch the results that you would expect from fluorescence recovery after photobleaching (FRAP) experiments with labels attached to each of these components individually (phospholipid, fibronectin and rhodopsin). (You should show three curves.) Ref: page 383 in text and the last slide in Unit 12 Part 1.