Overview of Cellular Respiration
KEY CONCEPT
The overall process of cellular respiration converts
sugar into ATP using oxygen.
Overview of Cellular Respiration
What is the purpose of Cellular Respiration?
• To release energy from food
molecules and make ATP!
• Why do we need ATP?
– To run chemical reactions that
keep us alive and functioning
Overview of Cellular Respiration
The Cellular Respiration Equation
Overview of Cellular Respiration
Cellular respiration makes ATP by breaking down sugars.
• Cellular respiration is aerobic, or requires oxygen.
• Aerobic stages take place in mitochondria.
mitochondrion
animal cell
Overview of Cellular Respiration
Overview of Cellular Respiration
Cellular Respiration
Overview of Cellular Respiration
• Glycolysis must take place first.
– anaerobic process (does not require oxygen)
– takes place in cytoplasm
– splits glucose into two three-carbon molecules
– pyruvic acid or pyruvate
– produces two ATP molecules
Overview of Cellular Respiration
Glycolysis Review Questions
•
•
•
•
Where does glycolysis take place?
Glycolysis energy yield?
Breaks glucose into TWO ________.
Is Oxygen required?
Overview of Cellular Respiration
The Krebs Cycle (Citric Acid Cycle)
• Takes place in the matrix of
the mitochondria
(intermembrane space)
• Uses the products of
glycolysis (pyruvic acid or
pyruvate) which are first
converted to Acetyl CoA
• Produces a small amount
of ATP (2 molecules)
• Produces carbon dioxide
as a waste product
• Sends high energy
electrons to the electron
transport chain with
electron carrying molecules
NADH and FADH2
Overview of Cellular Respiration
Krebs Cycle Review Questions
• Where does the Krebs Cycle take place?
• What are the products of the Krebs Cycle?
• What are the molecules produced that carry electrons to
the electron transport chain?
• How much ATP is produced in the Krebs Cycle?
Overview of Cellular Respiration
The Electron Transport Chain
• Uses high energy
electrons from the Krebs
cycle to convert ADP into
ATP
– NADH and FADH2
carry the electrons
through the ETC
• Most of the energy in
cellular respiration
comes from the ETC!
– Up to 34 ATP
molecules
Overview of Cellular Respiration
Electron Transport Chain
• Electrons carried by
coenzymes NADH and FADH2
pass through a series of
membrane-bound proteins (the
ETC) in the inner membranes
of the mitochondria of
eukaryotes
• Oxygen is required to accept
the “used” electrons and H+
ions at the end of the chain
– without oxygen to form
water and remove the H+
and electrons, the entire
system stops!
Overview of Cellular Respiration
Electron Transport Chain Review Questions
• Where does the electron transport chain occur in the
mitochondria?
• What chemicals carry electrons to the electron transport
chain?
• Why is oxygen required for aerobic respiration?
• How many ATP molecules can be produced from the ETC?
Overview of Cellular Respiration
Cellular Respiration is like a mirror image of photosynthesis
1
granum (stack of thylakoids)
1
chloroplast
6H2O
mitochondrion
matrix (area enclosed
by inner membrane)
6O2
2
ATP
and
6CO 2
energy
2
3
thylakoid
6CO2
energy
stroma
1 six-carbon sugar
energy from
glycolysis
and
6O 2
3
4
inner membrane
ATP
and
6H 2 O
C6H12O6
4
Overview of Cellular Respiration
• The equation for the overall cellular respiration process is:
C6H12O6 + 6O2  6CO2 + 6H2O
• The equation for the overall photosynthesis process is:
6CO2 + 6H2O  C6H12O6 + 6O2
• The reactants in photosynthesis are the same as the
products of cellular respiration.
Overview of Cellular Respiration
Comparing Photosynthesis and Cellular Respiration
Photosynthesis
Cellular Respiration
Function
Energy Storage
Energy Release
Location
Chloroplasts
Mitochondria
Reactants
CO2 and H2O
C6H12O6 and O2
C6H12O6 and O2
CO2 and H2O
Products
Equation
6CO2 + 6H2O
C6H12O6 + 6O2
C6H12O6 + 6O2
6CO2 + 6H2O