Bio Ch 9-14 (& 16)

Energy stored is ultimately coming from

Sun

Stored energy is released

Via breakdown of catholic pathway

Catabolic process

Fermentation (degradation of sugar or organic fuel without oxygen)

Aerobic respiration (most efficient), oxygen is consumed along with other organic fuel. (Most eukaryotic & prokaryotic, some prok do anaerobic)

Overall process= organic compound+oxygen—>CO2 + H20 + energy

Cellular respiration

Degradation of glucose

6C6H12O6 + 6O2–> 6CO2 +6H2O + energy (ATP)

(Breakdown of glucose = exergonic)

In order for cell to do work , must regenerate ATP from ADP & pi.

Relocation of e , releases energy stored in organic molecule

Redox

OIL RIG

note- reducing agent is the one that donated e

O2

One of the most powerful oxidizing agent

Activation energy serve as

Barrier for e flowing into lower state

H atoms are

Not directly transferred to O2 (first passed to e carrier ) —> NAD+ (reduced from NADH)

NAD+

Is reduced from NaDH after 2 e & 1 proton transfer

NADH shows charge is neutralized

NADH molecule produced during respiration shows stored energy

E reach oxygen from NADH

By being shuttled to the top

Note in respiration ETC is used to break fall of e to oxygen in many energy releasing steps

ETC

Mostly proteins in inner membrane of eukaryotic cells (& plasma membrane of respiring prokaryotes)

e transfer from NADH to oxygen= exergonic, series of rxn

Oxygen is the

Final e acceptor

Summary of cellular respiration

Most e flow downhill

Glucose—NADH—ETC—Oxygen

Glycolysis

Occurs in cytosol (degradation of glucose in 2 molecules of pyruvate)

In eukarya— pyruvate enters mitochondrian & is oxidized to compound acetyl CoA—> which enters citric acid cycle

In prokaryotic—> process takes place in cytosol

Dehydrogenases transfer e from substrates NAD+ & FAD , forming

NADH & FADH2

3rd step of respiration

ETC accepts e from NADH & FADH2

ATP synthesis of this = oxidative phosphorylation

In eukarya inner membrane is

Site of ETC & chemiosmosis = oxi phosphorylation

Oxidative phosphorylation

90% of ATP is generated

You add an inorganic phosphate to ADP

Substrate level phosphorylation

Generate smaller amount of ATP

During this enzyme transfers a phosphate group from a substrate molecule to ADP. (Substrate molecule is an intermediate which was generated during catabolism of glucose)

For each glucose degraded to CO2 and H2O

Cell make up 32 molecules of ATP

Glycolysis

Sugar splitting

(Glucose into two 3 C molecules)

2 phases of glycolysis

Energy investment = cell spent ATP

Energy payoff= ATP produced by sub.phos & NAD+ reduced to NADH

Net release = 2 ATP plus 2 NADH

(Note all C from glucose is converted to pyruvate)

Glycolysis can occur without

Oxygen , oxygen present , chemical energy can be extracted from pyruvate oxidation

Pyruvate enter

Mitochondrian via active transport

First converted to acetyl CoA (by multi enzyme complex)