Download Anaerobic Respiration

What if there is not enough or no
O2 present?

Alcoholic Fermentation (Yeast)
Pyruvate + NADH → Ethanol + NAD + CO2
Used in baking, beer & wine production

Lactic Acid Fermentation
Pyruvate + NADH → Lactic Acid + NAD
Strenuous exercise = can’t get all the O2 your cells need
so use lactic acid fermentation = Sore muscles!!!
Anaerobic Respiration:
Fermentation
The fate of the 2 pyruvate
molecules that are produced
by glycolysis depends on the
organism involved.
Anaerobic Respiration - Fermentation
KEY CONCEPT
Fermentation allows the production of a small
amount of ATP without oxygen.
•
If no oxygen is available, cells can obtain energy
through the process of anaerobic respiration.
• A common anaerobic process is fermentation.
•
Fermentation is not an efficient process and results in
the formation of far fewer ATP molecules than aerobic
respiration.
There are two primary fermentation processes:
1. Lactic Acid Fermentation
2. Alcohol Fermentation
Anaerobic Respiration - Fermentation
Lactic acid fermentation occurs when oxygen is not
available.
For example, in muscle tissues during rapid and vigorous
exercise, muscle cells may be depleted of oxygen. They
then switch from respiration to fermentation.
Anaerobic Respiration - Fermentation
The pyruvic acid formed during glycolysis is broken down
to lactic acid and energy is released (which is used to form
ATP).
Glucose → Pyruvic acid → Lactic acid + energy
Anaerobic Respiration - Fermentation
•The process of lactic acid fermentation replaces the
process of aerobic respiration so that the cell can have a
continual source of energy, even in the absence of oxygen.
•However this shift is only temporary and cells need
oxygen for sustained activity.
Anaerobic Respiration - Fermentation
•Lactic acid that builds up in the tissue causes a burning,
painful sensation.
Anaerobic Respiration - Fermentation
Alcohol fermentation occurs in yeasts and some
bacteria.
Pyruvic acid formed during glycolysis is broken
down to produce alcohol and carbon dioxide and is
released (which is used to form ATP).
Anaerobic Respiration - Fermentation
Glucose → Pyruvic acid → alcohol + carbon dioxide + energy
Anaerobic Respiration - Fermentation
• Fermentation is used in food production.
Cheese
Vinegar
Yogurt
Soy Sauce Bread
Olives/Pickles
Beer/Meade
Wine/Ale
[PPT] Anaerobic Respiration - Fermentation
The Beer and Wine Industry
• In wine making, special strains of
yeast are added to grape juice,
which is then sealed in airless
tanks for weeks. The yeast
ferments the sugar in the grapes,
glucose. The alcohol content
eventually reaches 10-12% and
the yeast are killed.
• Brewers of beer add yeast to
barley. The starch in barley is
broken down to glucose. In
fermenting the glucose, alcohol
is produced.
Baking with Yeast
• Bakers add the yeast
Saccharomyces cervisiae to
the ingredients for bread.
• Once inside the dough, the
yeast breaks down the
starch in the flour to glucose.
The yeast then ferments the
glucose, producing CO2 and
alcohol.
• The bubbles of CO2 cause
the bread dough to rise. The
alcohol produced evaporates
during baking.
Muscle Energy
• During periods of vigorous exercise, an animal may
not be able to provide enough oxygen to the muscles.
The muscles will continue to work using ATP from the
anerobic breakdown of glucose to pyruvate.
• Lactic acid accumulates in the muscles and soon
fatigue sets in. Lactic acid accumulation can cause
cramping of the muscles.
• After ceasing the strenuous activity, rapid breathing
eventually supplies the cells with oxygen. The lactic
acid is converted back to pyruvate and aerobic
respiration resumes.
Lactic Acid in the Food Industry
• The flavor of many
familiar dairy products is
due to lactic acid
produced by the
fermenting of glucose by
the bacterium
Lactobacillus.
• Yogurt, buttermilk, and
sour cream, as well as
many cheeses, are
manufactured by
culturing lactic acidproducing bacteria in milk
or cream.
**Fermentation & Running**
In our bodies certain muscle cells called fast twitch
muscles, have less capability for storing & using oxygen
than other muscles. When you run & these muscles run
short of oxygen, the fast twitch muscles begin using lactic
acid fermentation. This allows the muscles to continue to
function by producing ATP by glycolysis.
The muscles get enough ATP for quick energy spurts, or
shall we say sprints, but quickly become fatigued as their
stores of glycogen are used up. Eventually you cramp. This
is in part because the muscles lack sufficient ATP to
continue contracting. Also, lactic acid build up & must be
metabolized by the liver. Runners who sprint actually have
more muscle cells specialized for lactic acid fermentation
than do long distance runners.
**White & Dark Meat**
If you want to see what these muscles are like,
when you eat chicken or turkey the white meat is
fast twitch muscle. The dark meat is what is called
slow twitch muscle. This meat is dark because it
contains an oxygen building protein called
myoglobin. Note that the slow twitch muscles tend
to be wing or leg muscles where long term energy
endurance is required. The fast twitch muscles
tend to be more common in the breast where quick
response but not necessarily endurance is needed.
Also, wild animals tend to have more slow twitch
muscle than their domestic counterparts.