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 5

How is cellular respiration different from combustion?

How is it similar?

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 12

What is the structure of Mitochondria?

Where do different reactions occur?

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

Harvesting Energy 18

What is the net energy yield from glucose?

Total energy yield = ~ 30%

Where did rest of energy go?

2.5 ATP / NADH1.5 ATP / FADH

Prokaryotes vs Eukaryotes