Biological Energy

Campbell and Reece Chapter 9 - is written backwards - very advanced details at beginning and fundamental information at end

Reminder - "count" "calories"= kcal
2000 per day for a sedentary woman
Important that we do not lose calories (through urine or feces) except through urine in untreated diabetes.
Marathon - 3000 Cal aerobic. 100 yd dash -anaerobic

ATP's 3rd phosphate bond has lots of energy, and breaking that bond releases the energy, but interestingly, how cells use energy is to put that phosphate from ATP onto a molecule like an ion pump or muscle's myosin molecule.

TRANSPARENCY (Fig. 9.19) We get our energy mostly from (1) glucose, (2) glycogen (glyco-sugar, gen-give rise to) in muscle for use in muscle and in liver for glucose release to blood, (3) amino acids (with NH3 as waste), or (4) fat (mostly fatty acids are chopped down 2 carbons at a time to give acetic acid into acetyl CoA in the Kreb's cycle).

TRANSPARENCY (Fig. 9.1) photosynthesis to make glucose, cellular respiration to release energy
Reaction [for glucose, C6(H2O)6]: C6H12O6 + 6 O2 -> 6 CO2 + 6 H2O

TRANSPARENCY (Fig. 9.16) Overall, 1 glucose can give up to 38 ATP's, a few from glycolysis and the rest from the mitochondrion

TRANSPARENCY (Fig. 9.4) It is important to introduce NAD+ plus 2 H <-> NADH in oxidation - reduction reactions as a way to carry electrons.
lose electrons - oxidation (NAD+ is oxidized)
nicotinamide adenine dinucleotide
add electrons - reduction (NADH is reduced)

TRANSPARENCY (Fig. 9.8) Glycolysis is a compound word glyco-sugar, lysis-splitting. Glucose is split into 2 pyruvic acids
Use 2 ATP's make 4, net 2 make 2 NADH's plus 2 H+'s, the H+'s come from from "sugar"

TRANSPARENCY (Fig. 9.18) without oxygen, make ethanol or lactate (lactic acid).
Anaerobic glycolysis is used to deliver ATP quickly but wastefully (squandering glucose).
Make ATP's but need to regenerate NAD+ from NADH] to make.
Lactic acid contributes to fatigue in muscle and oxygen debt, and the liver eventually reconverts.
Anaerobic cellular "respiration" is needed in times of extreme exertion because the heart (cardiac output) is the limiting factor in delivery of oxygen to muscle.
Lactic acid is also made by bacteria in yogurt, sour cream, and cheese.

TRANSPARENCY (Fig. 9.17) fermentation - as in yeast is anaerobic. In cytosol. KINASE
i.e. without oxygen Substrate level phosphorylation makes ATP
Phosphoenolpyryvic acid (PEP) -> pyrivic acid

TRANSPARENCY (Fig. 9.10) Pyruvic acids generate 2 acetic acids, become Acetyl CoA's.
Kreb's cycle = citric acid cycle = TCA (tricarboxylic acid cycle) TRANSPARENCY (Fig. 9.11)
Takes place in the mitochondrion
A few ATP's are made plus NADH's and FADH2 are generated
Notice that CO2 is generated here.

The1953 Nobel prize in Physiology and Medicine was divided equally, one half awarded to: SIR HANS ADOLF KREBS for his discovery of the citric acid cycle and the other half to: FRITZ ALBERT LIPMANN for his discovery of co-enzyme A and its importance for intermediary metabolism.

TRANSPARENCY (Fig. 9.5) sugar-H2 + NAD+ -> (DEHYDROGENASE) "sugar" + NADH + H+
(in other words, H is split to H+ and e-)
Electron transport and oxidative phosphorylation use oxygen
cytochromes - these are iron - containing pigments (iron is in the form of heme)
Iron is not abundant, but it is important in biology.
NADH and FADH2 give electrons to cytochromes and oxygen

TRANSPARENCY (Fig. 9.15) Protons pumped, then flow down gradient making ATP's.
Something like an ion pump (we will cover that a lot later in the semester) in reverse is how most ATP is made, H+ (pH, proton) gradient runs through that molecule, like water running through turbines generating electricity, to generate electricity

TRANSPARENCY (Fig. 9.6) (like Fig 9.16 but with different emphasis)

This page was last updated 9/17/02

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