Using Energy
• All living things must be able to break down glucose
to produce energy.
Where do dogs get
their glucose?
Where do plants get their
glucose?
THEIR FOOD
PHOTOSYNTHESIS
Okay, so you’ve eaten a good meal & there’s plenty of
glucose in your body. Is this energy ready to be used?
NO
Your body needs to convert glucose into a form of
energy that it can use.
Glucose
ATP
Remember! ATP is the form of energy that your body
can use, so glucose needs to be converted into ATP!
Cellular Respiration &
Fermentation
Cellular Respiration
• The process of converting stored energy (glucose) into
energy the cell can use (ATP)
6O2 + C6H12O6  6CO2 + 6H2O + ATP
Oxygen + Glucose  Carbon Dioxide + Water + Energy
GLUCOSE
( C6H12O6 )
GLUC
( C6H
OSE
12O6 )
GLUC
( C6H
OSE
12O6 )
GLUC
( C6H
OSE
12O6 )
ENERGY
ATP
(Adenosine Triphosphate)
Cellular Respiration
If Oxygen
is
Available
Krebs Cycle
Electron
Transport
Chain
Glycolysis
If No
Oxygen is
Available
Fermentation
CR begins with
Glycolysis.
If oxygen is available,
the next step is the
Krebs Cycle & ETC.
If no oxygen is
available, the next
step is fermentation.
Glycolysis
1. The process by which glucose molecules are split into 2
pyruvic acid molecules while in the cytoplasm; 2 ATP are
produced
2 pyruvic acid molecules
Glycolysis
• The pyruvic acid may enter the mitochondria & complete
aerobic respiration…
OR
• It can remain in the cytoplasm & undergo anaerobic
respiration.
Aerobic Respiration
Cellular Respiration
If Oxygen
is
Available
Krebs Cycle
Glycolysis
Aerobic Respiration (Oxygen Available)
2. The pyruvic acid moves
into the mitochondria &
enters the Krebs Cycle.
3. During the Krebs Cycle,
2 ATP are produced as
well as 2 electron carrying
molecules (NADH &
FADH2).
– NADH & FADH2 carry
excited electrons.
KREBS CYCLE
CO2 is also produced
as a byproduct of
the Krebs Cycle!
ELECTRON
TRANSPORT
CHAIN
Aerobic Respiration
Cellular Respiration
If Oxygen
is
Available
Krebs Cycle
Electron
Transport
Chain
Glycolysis
4. Electron Transport Chain: energized electrons are moved
through the electron transport chain, generating 32 ATP.
The ETC takes place in the membranes of the mitochondria. The
electrons are carried through the ETC by proteins, which generates
ATP.
The energy from the electrons causes hydrogen ions (H+) to flow
through the mitochondrial membrane.
The flow of H+ ions drives ATP Synthase, which produces ATP.
Aerobic Respiration
5. Lastly, O2 accepts the used electrons & forms H2O &
some energy is lost as heat.
KREBS CYCLE
ELECTRON
TRANSPORT
CHAIN
Where does glycolysis take place?
A.
B.
C.
D.
Mitochondria
Cytoplasm
Nucleus
Chloroplast
Cytoplasm!
Where does the Krebs Cycle take place?
A.
B.
C.
D.
Mitochondria
Cytoplasm
Nucleus
Chloroplast
Mitochondria!
Where does the Electron Transport Chain take
place?
A.
B.
C.
D.
Mitochondria
Cytoplasm
Nucleus
Chloroplast
Mitochondria!
Aerobic Cellular Respiration
• Step 1 – Glycolysis, 2 ATP
produced
• Step 2 – Krebs Cycle, 2 ATP
produced
• Step 3 – Electron Transport Chain,
32 ATP produced
36 ATP produced TOTAL!
Anaerobic Respiration
Cellular Respiration
Glycolysis
If No
Oxygen is
Available
Fermentation
Anaerobic Respiration
• Occurs if NO oxygen is available!
• 2 types of fermentation could occur:
– Lactic Acid Fermentation: pyruvic acid turns into lactic
acid
– Alcoholic Fermentation: pyruvic acid turns into ethyl
alcohol
Lactic Acid Fermentation
• Occurs in muscle cells
– Lactic Acid builds up in your muscles, which causes pain &
soreness.
• Also used by bacteria, which are used in food production
(yogurt, sourdough bread, pickles, etc.)
Alcoholic Fermentation
• Yeast & other microorganisms perform this.
– Carbon dioxide is a byproduct.
– Used to help us make bread (CO2 makes the bread rise) &
wine.
Where does anaerobic respiration take place?
A.
B.
C.
D.
Mitochondria
Cytoplasm
Nucleus
Chloroplast
Cytoplasm!
Which pathway produces more ATP?
A. Aerobic Respiration
B. Anaerobic Respiration
Aerobic! Aerobic
produces 36 ATP,
while anaerobic only
produces 2 ATP.