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Harvesting Energy 1
Harvesting Energy
Topics you are not responsible for:The individual enzymatic steps of glycolysis, Krebs cycle and the ETCThe details of fat metabolism through β-oxidation
Be able to answer questions:Self-test #s 1,3,6-13
Harvesting Energy 2
Can dieting lengthen your life?
What is “calorie restriction” ?
Animal data – true for humans?
Why ???Hormesis theory
Activation of “longevity genes”
Reduced “free radicals”
Free radicals are normal product of cellular respiration
-- electron transport chain
-- H2O2, O2- ; OH-, etc
Harvesting Energy 3
Cellular Respiration
lies at center of cellular
metabolism
Produces:energy supply
& intermediates
for otherpathways
Harvesting Energy 4
How are different foods ‘processed’ into usable cellular energy?
Catabolism
Anabolism
Ultimatecatabolicproducts
Harvesting Energy 6
What are the 2 mechanisms of producing ATP?
ADP + Pi ATP
Substrate level ATP synthesis
-- glycolysis-- Krebs cycle
Chemiosmotic ATP synthesis
-- electron transport
Harvesting Energy 7
What are the overall stages of cellular respiration?
Where do these processes occur?
Under what conditions do they occur?
Terminology usage
Cellular respiration vs Aerobic respiration
Harvesting Energy 8
What are the principal chemical changesthat occur during glycolysis?
Oxidation & Priming Cleavage ATP synthesis
What is the energy yield from glycolysis?
Harvesting Energy 9
What are some other coenzymes and prosthetic groups required for metabolism?
NADH-- Vitamin B3 (Niacin)-- How are electrons
stored in NADH?FADH
-- need Vitamin B2 (Riboflavin)
Pyridoxal-phosphate-- need Vitamin B6 (Pyrodoxin)-- AA metabolism
RiboflavinPyridoxal-PO4
Harvesting Energy 10
Why is Arsenate poisonous?
AsO43- resembles and substitutes for PO4
3-
For example:Normal glycolysis reaction:
3-Phosphoglycerate + PO4 1,3-bisphosphoglycerate
In presence of Arsenate3-Phosphoglycerate + AsO4 1-arseno-3-phosphoglycerate
Harvesting Energy 11
What are the fate(s) of pyruvate?
What is the function of fermentation?
-- Pyruvate disposal
-- NAD+ recycling
Harvesting Energy 13
How is Pyruvate converted into Acetyl-CoA?
Pyruvate dehydrogenase-- Decarboxylation
What is Coenzyme-A?
Why is Acetyl-CoA importantin metabolism?
Harvesting Energy 14
Back to alcohol metabolism… What are the metabolic consequences on liver of alcoholism? (some of them!)
Weight lossArteriosclerosis heart attacksAcidosis kidney damageLiver cirrhosis
Consequences of NADH/NAD imbalance
Harvesting Energy 15
What are the function and major events of the Krebs cycle?
What are the end products?-- useful-- waste
Harvesting Energy 16
How does the Electron Transport chain pass energy from NADH to ATP?
Hydrogen Ion Gradient
Redox Potential ofNADH Q Cyt-c O2
-0.32 0.04 0.22 0.816
Increasing affinity for e-
E- Transport Chain ATP synthase
Loss of e- creates free radicals
Harvesting Energy 17
How is heat production enhanced in brown adipose tissue (BAT)?
What is BAT? ...WAT?
“Nonshivering thermogenesis”
Involves “Uncoupling” of e- transport from ATP synthesis
-- Thermogin transporter
Under Thyroid hormone control
Relationship to weight control