Energy in
a Cell
Cellular
Respiration
Cellular Respiration
• Cellular
respiration:
process where
mitochondria
break down food
molecules to
produce ATP.
(energy)
Cellular Respiration
• Three stages in
cellular
respiration:
glycolysis, citric
acid cycle, and
electron
transport chain.
Cellular Respiration
• Mitochondria is
called the
powerhouse of
the cell because
it is the site of
cellular
respiration.
Cellular Respiration
• More work a cell
does, the more
mitochondria it
has.
Cellular Respiration
• Glycolysis: first
stage of cellular
respiration.
Cellular Respiration
• Takes place in
the cytoplasm of
the cell.
Cellular Respiration
• One C6H12O6
(glucose) is
broken down into
2 pyruvic acid
molecules. (a 3 C
molecule)
Cellular Respiration
• For every
glucose molecule
broken down, 2
ATP molecules
are produced.
Cellular Respiration
• Next, the pyruvic
acid moves into
the mitochondria.
Cellular Respiration
• Citric acid cycle or Kreb’s
cycle : Pyruvic acid is
broken down in a series
of reactions to produce 2
CO2 and 1 ATP and
electrons are passed on
to the electron transport
chain.
Cellular Respiration
• Electron transport
chain: series of
proteins where
electrons are
passed.
Cellular Respiration
• Energy is released
as electrons are
passed from one
molecule to the
next.
Cellular Respiration
• The released
energy is used to
make ATP.
Overall:
• For every glucose that enters
cellular respiration 36 ATP
are produced.
Cellular Respiration
• Cellular respiration
can be classified as
aerobic: cellular
respiration
occurs in the
presence of
O2.
Cellular Respiration
• Most efficient
form of respiration.
Cellular Respiration
• Krebs cycle is
aerobic respiration.
Cellular Respiration
• Cellular respiration
can also be
classified as
anaerobic:
respiration
that proceeds
in the absence
of O2.
Cellular Respiration
• Glycolysis is
anaerobic
respiration.
Cellular Respiration
• Not as efficient as
aerobic. Only 2 ATP
formed.
Cellular Respiration
• In the absence of
O2, pyruvic acid
backs up and is
eliminated 2 ways:
Cellular Respiration
1. In you and me,
pyruvic acid is
converted to lactic
acid and builds up
in the muscles.
Cellular Respiration
2. In yeast, pyruvic
acid converted to
CO2 and ethyl
alcohol. This
makes bread rise.
Cellular Respiration
• Anaerobic
respiration is
also called
fermentation.
Cellular Respiration
• Which molecule has
the most stored
energy: fat or
carbohydrate?
Cellular Respiration
• Fat – it has
available energy for
51 ATP.