Cellular Respiration
Cellular Respiration
• All food contains energy
– Proteins, Lipids and
Carbs
• All cells have systems to
unlock and use this
energy
• The process of turning
food energy into ATP is
called cellular
respiration
Cellular Respiration
• All cells break down
molecules for energy
• Both autotrophs and
heterotrophs create
chemical energy from
food
• Heterotrophs break down
food that has been
consumed
• Autotrophs break down
food that they have
produced
Overview of Cellular Respiration
• Cellular respiration can
be broken down into
two different processes
– Aerobic Respiration
– Anaerobic Respiration
• Aerobic respiration
requires oxygen
• Anaerobic respiration
does not require oxygen
Overview of Cellular Respiration
• Cellular respiration has
a set chemical reaction
• Just like photosynthesis
there is a set pathway
with set inputs and
products
Overview of Cellular Respiration
Overview of Cellular Respiration
• What does this equations
remind you of?
• Photosynthesis and CR
are linked
• The products for
photosynthesis are the
reactants for CR
• The products for CR are
the reactants for
photosythesis
Mitochondria
• Think back to cell as a city
• What job did we give the
mitochondria?
• The mitochondria has two
main areas
• The matrix is the inner
space filled with fluid
• The inner membrane is a
folded membrane on the
inside the mitochondria
Mitochondria
• The aerobic parts of
cellular respiration are
performed in the
mitochondria
• Every part of cellular
respiration that involves
oxygen is done in the
mitochondria
Overview of Cellular Respiration
• Before we learn the in
depth view of glycolysis
lets investigate the overall
purpose of glycolysis
• Glycolysis is the breaking
of glucose into two
molecules of pyruvate in
the cytoplasm
• “Glyco” – Sweet
• “Lysis” – Split
Overview of Cellular Respiration
• In essence one
molecule of glucose (6
carbons) is being
snapped in half
• The product is two
molecules of pyruvate
(3 carbons)
• This release will give a
small amount of energy
Overview of Cellular Respiration
• Respiration can have two
pathways
– Aerobic or anaerobic
• These two pathways both
start with glycolysis
• Glycolysis happens in the
cytoplasm
• Glycolysis is a pathway
where one sugar is
broken in half
• Glycolysis produces 2
molecules of ATP
Fermentation
• If no oxygen is present
then the left overs from
glycolysis are fermented
• There are two different
types of fermentation
• Both of these types deal
with waste produced
from glycolysis
• The two different types
are
– Lactic acid fermentation
– Alcoholic fermentation
• Both happen in the
cytoplasm
Fermentation
• Lactic Acid
fermentation happens
in animal cells, fungi
and bacteria
• Animal muscle cells do
this when deprived of
oxygen
• It changes the three
carbon molecule from
glycolysis to lactic acid
Fermentation
• In animal cells lactic
acid fermentation
happens after a cell has
used all of its oxygen
– Sprinting over a short distance
or running a long distance
• It is important in the
production of milk,
yogurts, cheeses and
other dairy products
• It produces no ATP
Fermentation
• Alcoholic fermentation
happens in fungi and
plant cells
• Yeast is the most
common organism that
does this
• It changes pyruvic acid
to ethyl alcohol
• It produces no ATP
Aerobic Respiration
• Aerobic respiration
takes the left over
products from glycolysis
if there is oxygen
• It creates a large
amount of energy
• It is much more efficient
than anaerobic
respiration
Aerobic Respiration
• The products from
glycolysis enter the
mitochondria and are
broken down
• The breakdown
happens step by step
and involves different
areas of the
mitochondria
Efficiency of Anaerobic Respiration
• Anaerobic respiration is
a relatively inefficient
process
• Overall 2 molecules of
ATP are produced in
glycolysis
• No overall ATP is
produced in
fermentation
Efficiency of Anaerobic Respiration
• The overall increase in
ATP from one molecule
of glucose through
anaerobic respiration is
2 molecules of ATP
• This is because oxygen
is not present
• When oxygen is
present, much more
ATP is produced
Efficiency of Aerobic Respiration
• Anaerobic respiration
gave us 2 ATP
• Aerobic respiration
gives us total 36 ATP
• This shows that aerobic
respiration gives us
much more energy per
molecule of glucose
Efficiency of Aerobic Respiration
• This means that
organisms that undergo
aerobic respiration will
have much more energy
• This gives them the
energy to perform more
complex functions
In Review
• All respiration starts
with glycolysis
– Glucose is broken down
to smaller sugars
– Two net ATP
• Anaerobic respiration
finishes with
fermentation
– Lactic Acid
– Alcoholic
• Aerobic respiration
requires oxygen
• Aerobic respiration goes
through the Krebs cycle
and the electron
transport chain
– This gives overall 36 ATP
In Review