2. Getting Energy From Food 2
Getting Energy From Food
Not responsible
for:
Enzyme names and
molecular structures,
(unless discussed
specifically in class
Details of metabolic
pathways
3. Getting Energy From Food 3
What are the major pathways of
metabolism of our principal
energy sources?
Carbohydrates
Fats
Protein
What are the end-products?
What are the waste products?
4. Getting Energy From Food 4
Figure 3-33
How is energy transferred to ATP?
Substrate-level phosphorylation
Chemiosmotic phosphorylation
How is energy of ATP used?
-- energetically unfavorable Rxs
5. Getting Energy From Food 5
What are Functions of NAD, NADP, FAD?
Electron carriers
Oxidation / reduction reactions
NAD and catabolic reactions
-- substrate oxidation
-- H- used for ATP synthesis
NADP and anabolic reactions
-- substrate reduction
-- e.g., --COOH to C=O to C-OH
6. Getting Energy From Food 6
Overview of Carbohydrate Catabolism
You are expected to be familiar with the:
• functions and metabolic relationships between:
Glycolysis
Fermentation
Transition reaction
Krebs (TCA) cycle
Electron transport
• and their cellular locations
• roles/requirements for O2 and CO2 in these processes
7. Getting Energy From Food 7
Overview of Glycolysis
Substrate-level phosphorylation
vs
Chemiosmotic phosphoryltion
8. Getting Energy From Food
8
How does fermentation allow cells to
produce ATP in the absence of
oxygen?
-- detoxifying of pyruvate
-- regeneration of NAD
How long can this go on…?
What happens to the lactate?
Cori-cycle (a little physiology)
Lactic Acidosis
9. Getting Energy From Food 9
Oxidation of Pyruvate to Acetyl-CoA
The Pyruvate Dehydrogenase Complex
-- huge
-- highly regulated
Activators:
ADP, NAD, CoA
Inhibitors:
ATP, NADH, acCoA
10. Getting Energy From Food 10
How are triglycerides oxidized?
Fatty acids and glycerol
Beta-oxidation
1 FADH & 1 NADH / acCoA
How many FADH and NADH
would be produced from a 16
carbon FA?
12. Getting Energy From Food 12
Using NADH to make ATP
Electron transport and oxidative
phosphorylation
From glucose
Glycolysis ATP yield
____ NADH x ____ ATP _______
____ ATP _______
Transition Rx
____ NADH x ____ ATP x 2 pyr _______
Krebs cycle
____ NADH x ____ ATP x 2 pyr _______
____ FADH x ____ ATP x 2 pyr _______
____ GTP x ____ ATP x 2 pyr _______
Total 30
From a 12 carbon fatty acid
B-oxidation ATP yield
____ FADH x ____ ATP x 6 acCoA _______
____ NADH x ____ ATP x 6 acCoA _______
Krebs cycle
____ NADH x ____ ATP x 6 acCoA _______
____ FADH x ____ ATP x 6 acCoA _______
____ GTP x ____ ATP x 6 acCoA _______
Total 84
You should be able to complete a table to calculate energy yields from glucose or fatty acids (of any given length)
-- assuming 2.5 ATP per NADH (1.5 per glycolytic NADH) and 1.5 ATP per FADH
13. Getting Energy From Food 13
What are the
biosynthetic roles
Of these pathways?
