Respiration-- AKA “breathing”
Most associate respiration with the intake
of Oxygen and exhaling of Carbon Dioxide.
It is much more complicated than that!!
After Oxygen enters your bloodstream it combines with sugar
from your food intake to make ATP for energy. A by-product
of all this activity is Carbon Dioxide.
Respiration is called an AEROBIC process since it requires
Oxygen to take place.
ATP
In order for sugar to provide energy, it requires 3 steps:
1. Glycolysis– “splitting the sugar”
-happens in the cytoplasm of the cell
-6 Carbon glucose molecule is split into 2,
3 Carbon molecules called
“pyruvates”
-NAD+, an enzyme, picks
up high energy
electrons of hydrogen
to take to the
next stage. This forms
NADH.
- some ATP is also made
in this step
-The “pyruvates” continue
into step 2.
2. The Krebs Cycle—happens inside the mitochondria
--”fuel” in the form of pyruvic acid is modified for use
and becomes Acetyl CoA.
--the Acetyl CoA is completely broken down into
Carbon Dioxide, ATP and enzymes NAD+ and
FAD++ that become NADH and FADH2
--Carbon Dioxide becomes a by-product that you
breath out during
respiration.
--The enzymes carry the
high energy H+
into the next and
final step.
3. The Electron Transport System or ETS– in the mitochondria
cristae.
-Enzymes drop off Hydrogen at the
beginning of the ETS and then return
to Glycolysis or Krebs for another
H ion.
-Oxygen is key ingredient in ETS
FADH2
-it pulls the H down the
cristae to the end of the
chain.
-H releases energy each
time it jumps down the
pump
-end result is water and
Lots of ATP energy
Total energy output from Aerobic Respiration:
Glycolysis…………………..2 ATP
Kreb’s Cycle………………..2 ATP
Electron Transport Chain…32 ATP
Total...36 ATP (38)
These numbers are only true of respiration when oxygen is
present in the reaction. If no oxygen is present, the cell must
use an alternate form of respiration:
ANAEROBIC RESPIRATION
or
FERMENTATION
Anaerobic Respiration
cannot use the same 3 steps that aerobic
respiration uses because no oxygen is present to run the ETS.
Instead, anaerobic respiration relies on the first step,
Glycolysis, to supply the cell with energy.
Recall how many ATP are produced by the glycolysis process.
Glycolysis…………………..2 ATP
This is the Total Energy output for fermentation.
Although energy production isn’t great, it is better than the
alternative…nothing at all!!!
Although fermentation seems like a simple process, it must
be able to recycle the NADH in order to keep the process
going.
This is done by the pyruvic acid accepting the H+ ion to
make by-products allowing the NAD+ to return for more H+.
http://www.uic.edu/classes/bios/bios100/lectures/09_25a_fermentation-L.jpg
Two types of by-products are produced, depending on the
organism using the fermentation process:
Lactic Acid—found in human muscles and microorganisms
Ethyl Alcohol—found in yeast
These by-products
may provide benefits
to society in the form
of alcohol products,
canning process
benefits and
production of yeasty
bread products.
http://1.bp.blogspot.com/KwCaCv69Gsk/T0vbrrfXQRI/AAAAAAAA
Byk/S41salirjto/s1600/alcoholic_fermenta
tion.jpg
Lactic Acid build-up in human muscle cells causes muscle
soreness after strenuous exercise. Think about what you
do when you exercise (die is not a good answer here!!)
You start out pretty good, then begin to breathe faster,
then start to feel muscle fatigue, then run out of energy.
Muscle cells are forced to revert to anaerobic respiration
when Oxygen supplies cannot meet energy demand.
This is what results in fatigue and soreness after exercise is
attributed to lactic acid (a poison) build-up in muscle cells.
How most of
you would
look!
---How your
instructor
would look!!
---
Lactic acid is also produced by microorganisms in Oxygen free
environments.
--canning process produces anaerobic
conditions
--necessary to get “good” seal
on cans or must eat food right away
--correctly canned, food can last a
long time
--best canned foods are the
oldest…lactic acid becomes a
flavoring agent
--build-up will eventually create
high acid environment and
Cheese is continually
microorganisms cannot survive
pressed and sealed to
here
create the anaerobic
process necessary to
--cheese and yogurt, olives and
produce the different
Kraut, soy sauce all employ
flavors of cheese. The
aging process also
same process
contributes to flavor.
Soy sauce is fermented juice
from the soybean. It cannot
even be placed on the market
shelf until it is at least one
year old!!
Kraut lovers of the world…
Unite!!! Kraut is NOT rotten
cabbage!! It is fermented
cabbage and we love it!!
Ethyl Alcohol is a by-product released during fermentation of
sugar products by yeast cells.
This process is economically important for several reasons:
Bread relies on this process.
Yeast “breaks down” the sugar and flour carbohydrates.
The by-products released during the “rising” period help
create fluffy bread. Which by-product besides ethyl
alcohol is produced? What does it do?
How can you eat bread and not become inebriated?
The brewing industry also relies on yeast fermentation of
carbohydrates. They use the sugar in grains and fruits
to produce ethyl alcohol and carbon dioxide. Instead
of “driving off” the alcohol, it is bottled and marketed.
Beer is the
result of yeast
fermenting hops
and different
grain products.
Different grains
produce different
flavors of light
and dark brews.
Wine and champagne
are the result of fruit
fermentation. Aging
contributes greatly to
the flavor of wines.
Champagne bubbles
come from the addition
of Carbon dioxide.
It is easy when talking about bread and brew making to forget
the concept behind the process relies on no oxygen being
present.
What happens if oxygen is present in wine or brewing processes?
How can you check and make sure sufficient anaerobic conditions
are being met?
What ingredients would you consider essential if you wanted to
make your own brew or wine?
Saccromyeces cerivasae
“brewers yeast”, an
facultative anaerobe
Humans tend to be obligate
aerobes because we
depend so much on oxygen.
E. aerogenes, a
obligate anerobe.