Review Biology 1
Where does this occur in the cell?
What is the “Power House” of the cell?
Is this what keeps the cell alive?
Is energy important to a cell?
Does oxygen have to be present?
Does the process change if there is
no oxygen?
What is the big deal?
Why is this important?
What do we need to know?
Where does this occur?
Do you remember what the powerhouse of
the cell is?
MITOCHONDRIA
Is this what keeps the cell alive?
Do we need energy to live?
How do we get energy? What do we get
energy from?
Do the individual cells in our body have the
same needs?
Does oxygen have to be present in order
for us (as humans) to breathe?
How about for cells?
Are there other processes that happen in
the absence of oxygen?
What is the big deal?
Why is this important?
Why do we need to know this?
* Cellular Respiration Definition:
Is a process . . . (takes time, doesn’t happen all at once)
That releases energy. . . (ATP)
By breaking down food . . . (in the form of glucose)
In the presence of OXYGEN
Oxygen + Glucose
Carbon Dioxide + Water + Energy
What is the first step?
Glycolysis
(Bonus– no oxygen required for this step!)
Then what?
Krebs Cycle
-andElectron Transport Chain
Energy . . . Energy. . . Energy. . .
What is energy in a cell?
ATP (ADP)
Adenosine Triphosphate
(Adenosine Diphosphate)
(NAD+/NADH = electron carriers)
(FAD/FADH2 = electron carriers)
Glycolysis Definition:
Is a process . . . (it takes time, more than one step)
Where Glucose is broken in half . . . (food)
Producing 2 molecules of Pyruvic Acid
(which is used in the next step to create more energy!)
This takes energy to get it going –
It is like pedaling a bike . . . That first take
off from a stop takes energy!
(2 ATP used to break the glucose into 2 Pyruvic Acids)
Now Glycolysis is done –
4 ATP was produced (total)
2 ATP was used to get the cell going –
2 ATP net (4-2) gained by the cell
2 molecules of Pyruvic Acid is formed
(goes to the Krebs Cycle)
2 molecules of NADH formed
(goes to the electron transport chain)
Krebs Cycle
Is Aerobic
(Requires Oxygen)
Occurs in the Mitochondria
(Powerhouse of the cell)
Breaks down Pyruvic Acid to Citric Acid
Which is also broken down to:
Carbon Dioxide, 2 ATP,
.
4 NADH, 1 FADH2
What is NADH?
NAD+
Nicotinamide Adenine Dinucleotide
What is FADH2?
FAD
Flavine Adenine Dinucleotide
What are the H’s?
Hydrogens – High-Energy Electrons!
At the same time:
In the Electron Transport Chain
(Still in the Power House – Mitochondria)
(Still in the presence of Oxygen)
Uses the NADH and FADH2
To convert ADP to ATP
How does that happen?
Remember that Hydrogens are HIGHENERGY electrons
That ENERGY is captured by removing the
Hydrogen from NADH and FADH2
Then transferred by adding a phosphate
group to ADP – making ATP
This is the energy used by our cells!!!
From every molecule of Glucose –
A total of 36 ATP are produced!!!
2 ATP from Glycolysis (outside the mitochondria)
34 ATP from Krebs Cycle and Electron
Transport Chain (mitochondria)
Do you now understand why the
mitochondria is nick-named the Power
House of the cell?
So… what happens when there is NO
oxygen for the cell to use?
Fermentation
There are two types:
Alcoholic Fermentation
Lactic Acid Fermentation
Alcoholic Fermentation (anaerobic)
Used by yeasts and other microorganisms
Forms ethyl alcohol and carbon dioxide from
the Pyruvic Acid created during Glycolysis.
What is it that causes bread to rise?
Why do bread recipes need sugar?
What happens to the alcohol when baking
bread?
Lactic Acid Fermentation (anaerobic)
Where does this occur?
In our muscles!!!!
As oxygen is used up in our muscles, the
Pyruvic Acid created during glycolysis is
converted to lactic acid.
Feel the burn!!!