EPOB 1210 Lecture 17, 1996
Respiration (cont.)


This has been the 1446th visit to this site since Oct. 4, 1996.

Word roots:

an (G) = without, not, as in anaerobic
acet (L) = vinegar, as in acetic acid
gener (L) = beget, produce, as in electrogenic or genesis

RESPIRATION cont.
The link between Glycolysis and the Krebs Cycle is the Formation of Acetyl CoA via a multi-enzyme complex. Loss of CO2 and attachment of Coenzyme A which makes acetyl CoA more reactive. Also Reduces NAD+ to NADH (one per pyruvate = 2 per glucose)
(Fig. 9.10)

The KREBS CYCLE (FIG. 9.12).

Is a cycle consisting of redox reactions. 2 C compound combines with a 4 C compound and then 2 Cs are lost as CO2 getting back to 4 Cs.
See fig. 9.11 for steps; don't memorize except for what is produced:
2 ATP via substrate level phosphorylation.
A bunch of NADH and some FADH2
4 CO2 per glucose

ELECTRON TRANSPORT CHAIN

Most ATP is produced via a process called OXIDATIVE PHOSPHORYLATION involving the
ELECTRON TRANSPORT CHAIN in the inner mitochondrial membrane.

Fig. 9.5 = water down hill
Fig. 9.13 = electron flow and free energy change.

Electron transport chain is made up of electron carriers in the inner mitochondrial membrane. Most of the e- carriers are proteins
e.g. cytochromes (see Fig. 9.14)

CHEMIOSMOSIS = Coupling exergonic e- flow to ATP synthesis.
As e- move down the ETC some of the energy is used to pump protons (Fig. 9.16) creating a proton gradient called the PROTON-MOTIVE FORCE
This ELECTROCHEMICAL gradient is used to make ATP

The site of ATP production is ATP SYNTHASE (see Fig. 9.14)

Overview of respiration
(Fig. 9.15):

Euks. 36 ATPs max. from a molecule of glucose.
Proks. 38 ATPs max. from a molecule of glucose.
Max. not usually attained