Glycolysis
ATP
Oxygen
present
Oxygen
Absent
Aerobic
Respiration
Fermentation
ATP
 1 6-C molecule is
oxidized to produce
2 3-C molecules of
Pyruvic Acid
 All reactions take
place in the cytosol
of the cell
 Has a net yield of 2
ATP molecules for
every glucose
converted to pyruvic
acid
 DOES NOT
PRODUCE ATP
 NO OXYGEN
 Regenerates
NAD+
 2 common
Pathways
 Lactic Acid
 Ethyl Alcohol
 Pyruvic Acid converted into another
3-C compound (lactic Acid)
 Involves the transfer of 2H atoms
from NADH and H+ to pyruvic acid
 Plays a major role in manufacturing
food products
 Occurs in muscles during strenuous
exercise
 Eventually LA will be transported
back to liver where converted back
to pyruvic acid
 Yeast cells are added
 2 step pathway
 CO2 molecule is
removed from pyruic
acid
 Leaves a 2-C compound
 2H atoms are added to
the 2-C compound to
make ethyl alcohol
 H atoms come from
NADH &H+ regenerating
NAD+
 Basis for wine beer
and bread production
How efficient are the anaerobic pathways at obtaining energy
from glucose and using it to make ATP from ADP?
 Complete oxidation of glucose releases 686 kcal
 Production of a standard amount of ATP from ADP
absorbs 12 kcal
 2 ATP are produced from every glucose molecule
broken down by glycolysis
Efficiency of
Glycolysis
Energy required to make
ATP
==
-----------------------------------------Energy released by
oxidation of glucose
 Efficiency of glycolysis = 3.5%
 Much of the original energy contained in
glucose is still held in pyruvic acid
 NOT VERY EFFICIENT
 Larger animals have greater energy
requirements that cannot be satisfied by
anaerobic pathways