Transcript 6-HarvestingEner

Harvesting
Energy
Topics you are not responsible for:
The individual enzymatic steps of glycolysis,
Krebs cycle and the ETC
The details of fat metabolism through β-oxidation
Be able to answer questions:
Self-test #s 1,3,6-13
Harvesting Energy
1
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
2
Cellular
Respiration
lies at center of
cellular
metabolism
Produces:
energy supply
&
intermediates
for other
pathways
Harvesting Energy
3
How are different foods
‘processed’ into usable
cellular energy?
Catabolism
Anabolism
Ultimate
catabolic
products
Harvesting Energy
4
How is cellular respiration
different from combustion?
How is it similar?
Harvesting Energy
5
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
6
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
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7
What are the principal chemical changes
that occur during glycolysis?
Priming
Cleavage
Oxidation &
ATP synthesis
What is the energy
yield from glycolysis?
Harvesting Energy
8
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
Pyridoxal-PO4
Harvesting Energy
Riboflavin
9
Why is Arsenate poisonous?
AsO43- resembles and substitutes for PO43-
For example:
Normal glycolysis reaction:
3-Phosphoglycerate + PO4  1,3-bisphosphoglycerate
In presence of Arsenate
3-Phosphoglycerate + AsO4  1-arseno-3-phosphoglycerate
Harvesting Energy
10
What are the fate(s) of pyruvate?
What is the function
of fermentation?
-- Pyruvate disposal
-- NAD+ recycling
Harvesting Energy
11
What is the structure of Mitochondria?
Where do different reactions occur?
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12
How is Pyruvate converted
into Acetyl-CoA?
Pyruvate dehydrogenase
-- Decarboxylation
What is Coenzyme-A?
Why is Acetyl-CoA important
in metabolism?
Harvesting Energy
13
Back to alcohol metabolism… What are the metabolic
consequences on liver of alcoholism? (some of
them!)
Consequences of
Weight loss
Arteriosclerosis  heart attacks
Acidosis  kidney damage
Liver cirrhosis
Harvesting Energy
NADH/NAD
imbalance
14
What are the function and major
events of the Krebs cycle?
What are the end products?
-- useful
-- waste
Harvesting Energy
15
How does the Electron Transport chain pass energy
from NADH to ATP?
Loss of e- creates free radicals
E- Transport Chain
Hydrogen Ion Gradient
Redox Potential of
NADH
Q
Cyt-c
O2
-0.32
0.04
0.22
0.816
ATP synthase
Harvesting Energy
Increasing affinity for e16
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
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What is the net energy yield from glucose?
2.5 ATP / NADH
1.5 ATP / FADH
Prokaryotes vs
Eukaryotes
Total energy
yield = ~ 30%
Where did rest of
energy go?
Harvesting Energy
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