Download Fermentation - Biology R: 4(A,C)

Fermentation
What if there’s not enough oxygen?
• Fermentation is the process of converting
energy from glucose when there’s not
enough oxygen = anaerobic
• Less energy is produced and glycolysis
continues producing ATP
• Lactic acid or alcohol are also produced.
• Fermentation occurs in the cytoplasm of
your cells.
Quick Energy
• Cells contain small amounts of energy (ATP)
produced during cellular respiration
• After a few seconds, stored ATP runs out
• Lactic fermentation makes about 90 seconds
worth of energy – but then you’ll owe a big
oxygen debt
• Heavy breathing after exercise is necessary to
take in more oxygen
Long-term Energy
• Cellular respiration is the only way to
generate a continuing supply of ATP
• Cell respiration releases energy more slowly
than fermentation, but it is steady
• After 15-20 minutes of activity, the body starts
to break down fats and other stored
molecules for energy – results in weight loss
Lactic Acid Fermentation
– Strenuous exercise: When you exercise
vigorously, your muscles run low on oxygen, so
you begin to convert energy from pyruvic acid
after glycolysis of glucose without enough
oxygen. As a result of fermentation, lactic acid
forms and makes your muscles cramp.
C6H12O6 + low O2
glucose
CO2 + lactic acid + energy
carbon
dioxide
Alcohol Fermentation
– Yeast and some bacteria do not have mitochondria, so they
use alcohol fermentation to break down pyruvic acid from
glycolysis.
– Bread: Yeast break down pyruvic acid after glycolysis of
glucose in the flour to release energy. As a result of
fermentation, alcohol is released into the air and carbon
dioxide bubbles make the bread rise.
C6H12O6 + low O2
glucose
CO2 + alcohol + energy
carbon
dioxide
Fermentation
C6H12O6 + low O2
sugar
oxygen
(glucose)
CO2 + waste + energy
carbon
dioxide
• Requirements:
– C6H12O6 – organic
sugar that comes from
digested food eaten
– Low O2 – oxygen is in
low supply or not
there at all
• Products:
– CO2 – carbon dioxide is
released
– Waste– alcohol, or
lactic acid in humans,
is released as a waste
product
– Energy – chemical ATP
energy is released
Energy & Exercise Review
• For a few seconds of intense activity, your body uses
small amounts of ATP stored from glycolysis and
cellular respiration.
• After a few seconds, your body uses ATP from lactic
acid fermentation, but only lasts 90 seconds.
• For longer activities, your body uses ATP from
cellular respiration breaking down glycogen
(carbohydrate) stored in your muscles and tissues,
but only lasts 15-20 minutes.
• For long activities, your body breaks down other
stored molecules, such as fats.
Let’s Compare all 3!
Photosynthesis
6CO2 + 6H2O + light energy
C6H12O6 + 6O2
Respiration
C6H12O6 + 6O2
6CO2 + 6H2O + energy
Fermentation
C6H12O6 + low O2
CO2 + waste + energy