Chemical Pathways
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Transcript Chemical Pathways
Chemical Pathways
Food is your source of energy!
Calorie-amount of energy needed to raise the temperature of
1 gram of water 1 degree Celsius
1 kilocalorie is 1000 calories
Kilocalories are actually on the food package but we call it
CALORIES
Cells use calories from food to make ATP
Cellular energy
Break off the phosphate molecules and we release energy
Form ADP
ADP is made back into ATP through cell respiration
Plants and animals carrying out cell respiration.
Let’s watch a movie first.
http://www.brainpop.com/science/cellularlife
andgenetics/cellularrespiration/
Username: bcps
Password: brainpop
Cell Respiration Overview
Release energy by breaking down glucose and other food
molecules with the help of oxygen
Equation
Oxygen + glucose= carbon dioxide + water+ ATP
Take place in the mitochondria
Two types of respiration:
Anaerobic-does not use oxygen
Aerobic-uses oxygen
Glycolysis
Takes place in the
cytoplasm of the cell
INPUTS: Glucose and 2
molecules of ATP
OUTPUTS: 4 ATP (net
gain of 2) and pyruvic acid
NADH holds electrons for
later use to create tons of
energy
Called an electron carrier
Fermentation
If oxygen is not present, fermentation takes place after
glycolysis
Fermentation-releases ATP from food without the use of
oxygen
Two main types
Alcoholic fermentation-yeast form ethyl alcohol and carbon dioxide as
waste; cause bread dough to rise
Lactic acid fermentation-lactic acid is produced
Created when your muscles do not have enough oxygen to produce
ATP when exercising
o Buildup of lactic acid creates a painful burning sensation
Unicellular organisms use to make food like yogurt, cheese, sour
cream, pickles, sauerkraut
Section 9.2 Kreb Cycle (citric acid
cycle)
Pathway is aerobic-needs oxygen
to function
Pyruvic acid from glycolysis
enters the mitochondria
Carbon is removed from this
acid to form carbon dioxide
Pyruvic acid will turn into acetyl
CoA
Acetyl CoA will turn into citric
acid
Citric acid goes through the
cycle to form ATP, carbon
dioxide, NADH and FADH2
(these two items hold high
energy electrons that will be
used in the next cycle)
Electron Transport Chain
NADH and FADH2 is passed
to this stage in the membrane
of the mitochondria
The electrons that are in
these two molecules are
passed along the carrier
proteins in the membrane
Water will form at the end of
this chain
Kreb and electron transport
chain produce 36 ATP per
one molecule of glucose
We don’t always consume glucose
so how do we make ATP?
Complex carbohydrates are broken down into glucose.
Lipids and proteins can be broken down into molecules that
enter the Kreb cycle and electron transport chain
Energy and exercise
Quick energy
Enough ATP for a short time
Rest of time ATP is produced by lactic acid fermentation
After race, heavy breathing is used to increase oxygen to repay
the oxygen debt
Long term energy
For exercise that is 90 seconds or longer, body relies on cell
respiration
Use stored energy in the form of glycogen
Body will begin to break down other stored molecules like fat