CHAPTER 7
Cellular
Respiration
7.1 SUNLIGHT POWERS LIFE
• AUTOTROPHS
– Makes its own food
• Also called PRODUCERS - produce
organic molecules to serve as food for their
ecosystem
Ex: plants/algae transform sun’s energy to
sugar – PHOTOSYNTHESIS
• HETEROTROPHS
–can’t make their own food
–Also called CONSUMERSconsumes other organisms, depend
on producers for food
Many organisms harvest energy stored in
foods through. . .
• CELLULAR RESPIRATION –
chemical process
uses O2 to
convert energy
in food into ATP
–ATP-main energy
supply for plants
and animals
7.2 FOOD STORES CHEMICAL
ENERGY
ENERGY- ability to perform work
3 types of energy:
1. KINETIC- energy of motion
• Ex: climbing up stairs
2. POTENTIAL-energy that is stored
due to objects position/arrangement
• Ex: the motion of climbing stairs is
kinetic energy-once you reach the
top of a slide the energy becomes
potential- when you slide down a
slide, the energy becomes kinetic
3. CHEMICAL
–Potential to perform work based on the
arrangement of atoms within molecules
–O2 converts molecules such as fats,
carbohydrates, proteins into ATP
• Releases potential energy
• Different forms of energy may be
interconverted, as in
this example of the
conversion of
potential energy
into kinetic energy
And finally into heat
(thermal energy)
7.3
PROVIDES ENERGY
FOR CELLULAR WORK
• ATP (Adenosine triphosphate)
- “adenosine”- made of adenine and ribose
–“triphosphate”– three phosphate groups
When ATP is involved in a chemical
reaction phosphate bonds are
broken releasing energy
When one phosphate group
is removed, ATP becomes
ADP
ATP CYCLE
• ATP continually converted to ADP
• ATP is “recyclable” – can be restored
by adding a phosphate group
REVIEW
1. Which type of organism can make its
own food?
2. Which type cannot make its own food?
3. When you walk up stairs you are using
this type of energy?
4. When you are at the top of the stairs
you have this type of energy.
5. What is the main energy supply for
plants and animals?
6. ATP is produced through this process.
7. Explain how humans get energy from
the sun.
8. What does ATP stand for?
9. How does ATP release energy?
10.ATP is continually converted into what
molecule?
Overall Equation for Cellular
Respiration
Cellular respiration’s main function is to
generate ATP for cellular work
Structure of the Mitochondria
A Road Map for Cellular
Respiration
• Cellular Respiration consists of a series of
reactions.
• A specific enzyme catalyzes each
reaction.
• The three reactions that take place are:
Stage 1: Glycolysis
Stage 2: The Krebs Cycle
Stage 3: Electron Transport Chain
Stage 1:Glycolysis
• Occurs in the cytoplasm of the cell
• Reaction: Sugar (6C)  2 Pyruvates (3C)
• Produces:
–2 ATP molecules
–2 NADH2
• How does the Pyruvic Acid get into the
Mitochondrion?
–Pyruvate is converted to Acetyl CoA!
• Transition Reaction - Let’s take a look!
Stage 2: Krebs Cycle
• Occurs in the mitochondria
• Cyclical series of reactions which breaks
down acetyls releasing CO2
• Produces:
–2 ATP’s
–6 NADH2
–2 FADH2
Up to this point, the molecule of glucose
has been broken down to form 4 CO2’s
Only 4
ATP’s have
been
formed
during:
Potential energy of
NADH2 and FADH2
can be released in
Electron Transport
Chain
•Glycolysis
&
•Krebs
Cycle
Stage 3:Electron Transport Chain
Occurs along inner membrane of mitochondrion
Electron Transport Chain
• Hydrogen ions are stripped of their
energy, and large amounts of ATP are
formed.
–Takes place in the inner membrane of
the mitochondrion.
–The used ions and Hydronium are
combined with
–oxygen to form H2O.
–Produces:
• 34 ATP
Adding Up the ATP Molecules
2 ATP
2 ATP
Electron transport
chain
34 ATP
7.6 Some Cells can produce ATP
without oxygen being present
• If oxygen is not
present,
fermentation
allows cells to
make ATP
Fermentation In Human Muscles
• Fermentation
produces 2 ATP’s
per molecule of
glucose broken
down
• Fermentation can
make enough
ATP for short
bursts of activity
such as a sprint
to catch the bus!
Exercise and Lactic Acid
Fermentation
• If muscles use oxygen faster
than it can be delivered by
the lungs, then they switch
to anaerobic respiration.
• Fermentation in muscle cells
produces Lactic Acid
• This causes fatigue, pain, &
cramps.
• This is the burn you feel
when you exercise!
Fermentation in Microorganisms
• Yeast, when in an anaerobic
environment, ferment sugar and
other foods
• This produces ALCOHOL!
• Thus, it is called alcoholic
fermentation
• CO2 is released
• Yeast are used in the making of
bread, wine, and beer making
• Fungi and bacteria produce
lactic acid during fermentation
and are used to produce cheese
products
Review of Cellular Respiration
Glycolysis
Lactic Acid
Fermentation
Alcoholic
Fermentation
Krebs Cycle
Electron Transport
Chain
REVIEW
1. What does ATP stand for?
2. Why is ATP recyclable?
3. What are the products of cellular
respiration?
4. Why is mitochondria folded?
5. What are the three stages of cellular
respiration?
6. Where does glycolysis occur?
8. What is produced from glycolysis?
9. Where does the Kreb’s cycle occur?
10. What is produced from the Kreb’s cycle?
11. Where does electron transport occur?
12. What is formed from electron transport?
13. When does fermentation occur?
14. What is produced from fermentation in
muscles?
15. What is produced from fermentation in
microorganisms?