Cellular Respiration
Where the fuel is burned.
Mitochondria
 Double membrane bound
organelle.
 Outer membrane encloses
the entire structure.
 Inner membrane encloses
a fluid-filled matrix.
 Folded cristae project into
the matrix. Increases
surface area
 Small circular DNA.
Mitochondria
 It is the site of cellular respiration,
 a catabolic, “breaking down”,
 Exergonic, “energy releasing”,
 Aerobic: “oxygen requiring” process
that uses energy extracted from glucose
to produce ATP.
ATP
 Energy is released
from ATP when a
phosphate group is
removed.
 ATP is changed to
ADP.
 ADP can then be
“recharged” to ATP
again.
Overall Reaction:
C6H12O6 + 6O2 → 6CO2 + 6H2O + 36 ATP
+ Heat
 Do the products and reactants look
familiar?
Cellular Respiration
Overview
 Breakdown of glucose begins in the
cytoplasm, the liquid matrix inside of all
cells
 At this point life diverges into two forms
and two pathways
 Anaerobic cellular respiration also called:
fermentation
 Aerobic cellular respiration, commonly just
called cellular respiration.
Stages of Cellular Respiration
Cellular Respiration can be broken
down into three stages:
1. Glycolysis (splitting of sugar)
2. Kreb’s Cycle also known as the Citric Acid
Cycle
3. Electron Transport Chain (ETC) also called
chemiosmosis
Glycolysis
 Occurs in the cytoplasm of all cells
 Series of reactions which break the 6carbon glucose molecule down into two 3carbon molecules called pyruvate.
 Process is an ancient one-all organisms
from simple bacteria to humans perform
it the same way.
 Yields 2 ATP molecules for every one
glucose molecule broken down
 Yields 2 NADH per glucose molecule
Aerobic Cellular
Respiration
 Oxygen required = aerobic
 2 more sets of reactions which occur in a
specialized structure within the cell called
the mitochondria
 1. Kreb’s Cycle
 2. Electron Transport Chain
Kreb’s
Cycle
Kreb’s Cycle (Citric Acid Cycle)
 Occurs in the mitochondrial matrix
 Completes the breakdown of glucose
 Takes the pyruvate (3-carbons) and breaks it
down, the carbon and oxygen atoms end up
in CO2 and H2O
 Hydrogens and electrons are stripped and
loaded onto NAD+ and FAD to produce
NADH and FADH2
 Production of only 2 more ATP but
loads up the coenzymes with H+ and
electrons which move to the 3rd stage
Kreb’s
Cycle
Electron Transport Chain (ETC)
 Occurs along the inner mitochondrial
membrane.
 Electron carriers loaded with electrons and
protons from the Kreb’s cycle move to this
chain-like a series of steps (staircase).
 As electrons drop down stairs, energy
released to form a total of 32 ATP
 Oxygen waits at bottom of staircase, picks
up electrons and protons and in doing so
becomes water. Cleans up the area!!
Energy Tally
 36 ATP for aerobic vs. 2 ATP for anaerobic
 Glycolysis
2 ATP
 Kreb’s
2 ATP
 Electron Transport
32 ATP
36 ATP
 Anaerobic organisms can’t be too energetic but
are important for global recycling of carbon
Kreb’s
Cycle
ETC
Releasing chemical
energy
Use your “Releasing
Chemical Energy”
worksheet to answer
questions from the
video.
Kreb’s
Cycle
Anaerobic Cellular
Respiration: Fermentation
 Some organisms thrive in environments with
little or no oxygen
 Marshes, bogs, gut of animals, sewage
treatment ponds
 No oxygen used = ‘an’aerobic
 Results in no more ATP, final steps in these
pathways serve ONLY to regenerate NAD+ so it
can return to pick up more electrons and
hydrogens in glycolysis.
Alcoholic Fermentation
 Products: ethyl alcohol,
carbon dioxide and the
energy carrier NAD+
 Release energy from food
molecules by producing 2
ATP molecules.
 Yeast: dough rises due to
carbon dioxide.
 Bacteria: present on grapes
creates the alcohol found in
wines.
Lactic Acid Fermentation
 Product: lactic acid and the energy
carrier NAD+
 Rapid exercise. Body cannot get
enough oxygen.
 Run out of oxygen. Produce ATP
by lactic acid fermentation causing
sore muscles.
 Unicellular organisms – lactic acid
(waste)
 Examples: cheese, yogurt,
buttermilk
Photosynthesis / Cellular
Respiration
Use your
“Energy and
Chemistry of
Life” worksheet
to answer
questions from
the video.