Any plant or man who dies
adds to Nature's compost heap
becomes the manure without which
nothing could grow nothing could be created
Death is simply part of the process
Every death even the cruellest death
Drowns in the total indifference of Nature
Nature herself would watch unmoved
if we destroyed the entire human race
I hate Nature
-Peter Weiss ... Marat ...Sade 1965

Audesirk, Audesirk & Byers Chapters 6 & 8

Today's musical selection
Jay and the Americans - Only in America


Metabolism is the general term for two kinds of reactions:
(1) catabolic reactions (breakdown)
(2) anabolic reactions (constructive)

Energy saved mostly through photosynthesis (Chapter 7, does not fit in this one semester)
released through "respiration" ("respiration" applies to breathing and cellularrespiration)

Figure 6-8
ADP plus phosphate <-> ATP involved in storage and release of energy
ATP made of Adenine, ribose and 3 phosphates, energy stored in 3rd phosphate bond

Figure 6-5
"Burning" glucose

Figure 6-3
substrates (reactants)-> products

Figure 6-13
Simplified metabolic pathways
Reminder: enzymes are named with suffix "-ase."

Figure 6-14
overcome energy of activation - catalysts - enzymes


Energy - kinetic and potential (later, discussing bioelectricity, potential will also be Volts)
First law of thermodynamics - energy of universe is constant
Second law - things become more disordered
Humanities: a 10 page science fiction story Isaac Asimov, The last Question in which it is asked what happens after the universe is dissipated.)
Energy flows as entropy increases.
In general, heat is waste and not useful.
BTU's (British thermal units, which can be converted to calories) imply that energy and heat are related.
Heat stored in energies of covalent bonds in kcal / mol
Free energy can be used for work = what is stored in bonds minus what is wasted as heat

Figure 6-3
e.g. cellular respiration C6H12O6 -> 6CO2 +6H2O + energy
the free energy is 686 kcal/mol


Figure 8-10
Store glucose energy into ATP
38 of them generated when respiration is complete
40.3% efficient, the rest is heat, usually considered as waste but useful in temperature regulation in warm blooded animals, homoiotherms, homeotherms.

It is easy to mistakenly think that energy use is only by muscles. However, a lot of the body's energy is used in transport and in reactions. ATP transfers its 3rd phosphate to molecules and the phosphate is then released as inorganic phosphate to be eventually added to ADP to make ATP.

Figure 6-19
Optimum tempreature for human enzyme may be near 37oC, body temperature. For a thermophilic bacterium, it may be very high, useful in PCR (polymerase chain reaction). Also, optimum pH for pepsin (proteolytic enzyme in stomach) is acidic while for amylase (polysaccharide enzyme in saliva) is slightly basic.

Biological Energy

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.

Figure (Chapter 6 opener)
(also Chapter 6 case study, energy unleashed, p. 101 and revisited, p. 113)
Marathon - 3000 Cal aerobic. 100 yd dash -anaerobic

Figure 6-10
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.

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).

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


Figure 8-10
Overall, 1 glucose can give up to 38 ATP's, a few from glycolysis and the rest from the mitochondrion


Figure 8-2
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)

Figure 8-1
Glycolysis is a compound word
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"

Anaerobic glycolysis

Figure 8-4
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.

Krebs cycle

Figure 8-9
Pyruvic acids generate 2 acetic acids, become Acetyl CoA's.
Kreb's cycle = citric acid cycle = TCA (tricarboxylic acid cycle)
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.

Electron transport

Figure 8-8
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

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

Questions used in 2007 relating to this outline

"Thermophilic" is a term applied to
(a) warm blooded animals.
(b) enzymes like pepsin that function well in stomach acid.
(c) entropy.
*(d) bacteria whose enzymes are used in PCR (the polymerase chain reaction).
(e) counting calories.

Hydrogen ions are pumped across a membrane, then, when they run back, they generate ATP. This is a simplified statement of
(a) thermodynamics.
(b) anaerobic glycolysis.
(c) the role of lactic acid in fatigue.
*(d) the electron transport chain.
(e) translation.

686 kcal per mole describes
(a) acetyl CoA.
*(b) energy from glucose breakdown.
(c) NAD+ and NADH.
(d) homeotherms.
(e) urea formation resulting from amino acid catabolism.

"Exerogonic" is a term applied to
(a) cell drinking.
(b) the "central dogma" of cell biology.
*(c) reactions.
(d) protein synthesis.
(e) apoptosis.

About what fraction of ATP is made by glycolysis when respiration is aerobic?
*(a) 1/16
(b) 1/4
(c) 1/2
(d) 3/4
(e) 15/16

In the delivery of biological energy
(a) sucrase gets used up when it generates glucose and fructose.
(b) the mitochondria use CO2 to produce O2.
(c) heat and entropy are captured and stored in ADP.
(d) glucose is taken into muscle (when insulin is low) where it is converted into triglycerides.
*(e) phosphate is typically transferred from ATP to another molecule.

Questions used in 2002 relating to this outline (and other outlines)

In the delivery of biological energy
(a) sucrase gets used up when it generates glucose and fructose.
*(b) phosphate is typically transferred from ATP to another molecule.
(c) heat and entropy are captured and stored in ADP.
(d) the end-product feeds back to inhibit the rate-limiting enzyme.
(e) the mitochondria use CO2 to produce O2

A reaction that requires oxygen is called
(a) autotrophic.
(b) fermentation.
(c) anabolic.
(d) reduction.
*(e) aerobic.

Kilocalories, those "calories" you count when you are dieting, are a measurement of
(a) water content of food and drink you consume.
(b) amino acid content of food.
*(c) energy available in food.
(d) relative fat content of food.
(e) relative carbohydrate content of food.

The fundamental function of aerobic respiration in cells is
(a) production of glucose.
*(b) the release of energy.
(c) storage of entropy.
(d) the replication of DNA.
(e) biosynthesis of triglycerides.

In which cellular organelle is most of the ATP produced from thorough glucose catabolism?
(a) nucleus
(b) rough endoplasmic reticulum
*(c) mitochondrion
(d) flagellum
(e) chloroplast

If animal muscle cells are depleted of sufficient levels of oxygen during use, anaerobic glycolysis will result and pyruvic acid will be converted into
*(a) lactic acid.
(b) carbon dioxide.
(c) glucose.
(d) glycogen.
(e) oxygen.

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