The document discusses how cells derive energy from the breakdown of carbohydrates, fats, and proteins through metabolic pathways. The major pathways discussed are glycolysis, the Krebs cycle, and oxidative phosphorylation. These pathways break down nutrients into smaller units, produce ATP through substrate-level phosphorylation and oxidative phosphorylation, and generate electron carriers like NADH and FADH2. The pathways are integrated through shared intermediates like pyruvate and acetyl-CoA to allow the cell to efficiently derive energy from different nutrient sources.

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INTEGRATED
METABOLISM
EVY YULIANTI
evy_yulianti@uny.ac.id

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Getting Energy From Food
Not responsible
for:
Enzyme names and
molecular structures,
(unless discussed
specifically in class
Details of metabolic
pathways

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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?

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Figure 3-33
How is energy transferred to ATP?
Substrate-level phosphorylation
Chemiosmotic phosphorylation
How is energy of ATP used?
-- energetically unfavorable Rxs

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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

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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

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Overview of Glycolysis
Substrate-level phosphorylation
vs
Chemiosmotic phosphoryltion

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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

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Oxidation of Pyruvate to Acetyl-CoA
The Pyruvate Dehydrogenase Complex
-- huge
-- highly regulated
Activators:
ADP, NAD, CoA
Inhibitors:
ATP, NADH, acCoA

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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?

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Krebs Cycle

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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

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What are the
biosynthetic roles
Of these pathways?

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15. Integrated Metabolism (Note Metabolic Linkage by G6-P, Pyruvic
Acid and Acetyl CoA)

16. Dominant Absorptive
Reactions:
Most cells oxidize
glucose to ATP, CO2
and H2O

17. Postabsorptive State Reactions

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