Download Respiration

Respiration
Chemical
C6H12O6 + O2

*Balanced
C6H12O6 + 6O2
 6CO2
CO2
+ ATP
+ ATP
+ H2O
+ 6H2O
Purpose?
• Provide energy for other processes
– Chemical reactions / metabolic processes eg protein
synthesis
– Active transport of material into cells
– Movement eg muscle contractions, to operate flagella
– MRS GREN…
– …to ultimately stay alive!
Why ATP?
Structure…Chemists only..
Recycling of ATP + Phosphorylation
Energy needed to turn
ADP + Pi back to ATP.
Provided by respiration
Energy released in cells
(eg muscle) when last
bond in ATP broken.
Makes ADP + Pi
Parts of a Mitochondrion
Outer membrane
Cristae (folds of
inner membrane)
Inner membrane
Key Steps & Locations
= “sugar splitting”
Cytoplasm
Mitochondria (in matrix = fluid filled interior)
Mitochondria (on inner membrane)
Key Steps
*Other names…
Krebs cycle = citric acid cycle
Electron transport chain = respiratory chain, oxidative phosphorylation
*Detailed Steps
Respiration
Glycolysis
Anaerobic
Glycolysis literally means "sugarsplitting." In glycolysis, the six-carbon
sugar glucose is split into two
molecules of pyruvate, also called
pyruvic acid. This process produces a
net gain of two ATP molecules. The
resulting molecules of pyruvate each
have three carbon atoms. Glycolysis
takes place in the cell's cytoplasm. The
remainder of cellular respiration takes
place in organelles called
mitochondria.
Aerobic
The Krebs Cycle
The Krebs Cycle takes place in the fluidfilled area inside the inner membrane of
the mitochondria known as the matrix.
Some ATP (2ATP) and other energy
carrying molecules are produced here.
The gas carbon dioxide is a byproduct of
this process.
The Electron Transport Chain
Most of the ATP is produced in this last
step of cellular respiration. Electron
transport takes place in the infoldings of
the inner-membrane of the
mitochondria. These infoldings are
called cristae. At the end of electron
transport, oxygen combines with
hydrogen ions and electrons (e-) to form
water. ½O2 + 2H+ + 2e- → H2O
Overall Process
glucose + oxygen → carbon dioxide +
water + 38 atp
Fermentation
In the absence of oxygen, the cell resorts
to anaerobic metabolism. In animal cells,
pyruvate is converted to lactic acid. In
yeast and bacteria, the pyruvate is often
converted to ethanol. In both cases, no
new ATP is produced, so the net
production of the energy-carrying
molecule is only the two molecules of ATP
produced in glycolysis.
Glycolysis
Glycolysis literally means "sugar-splitting." In glycolysis,
the six-carbon sugar glucose is split into two molecules of
pyruvate, also called pyruvic acid. This process produces
a net gain of two ATP molecules. The resulting molecules
of pyruvate each have three carbon atoms. Glycolysis
takes place in the cell's cytoplasm. The remainder of
cellular respiration takes place in organelles called
mitochondria.
The Krebs Cycle
The Krebs Cycle takes place in the fluid-filled area inside
the inner membrane of the mitochondria known as the
matrix. Some ATP and other energy carrying molecules
are produced here. The gas carbon dioxide is a byproduct
of this process.
The Electron Transport Chain
Most of the ATP is produced in this last step of cellular
respiration. Electron transport takes place in the
infoldings of the inner-membrane of the mitochondria.
These infoldings are called cristae. At the end of electron
transport, oxygen combines with hydrogen ions and
electrons (e-) to form water. ½O2 + 2H+ + 2e- → H2O
Overall Process
glucose + oxygen → carbon dioxide + water + 38 atp
Fermentation
In the absence of oxygen, the cell resorts to anaerobic
metabolism. In animal cells, pyruvate is converted to
lactic acid. In yeast and bacteria, the pyruvate is often
converted to ethanol. In both cases, no new ATP is
produced, so the net production of the energy-carrying
molecule is only the two molecules of ATP produced in
Structure & Function #1
Outer membrane
Cristae (folds of
inner membrane)
Inner membrane
Structure & Function #2
Outer membrane – regulates passage of materials
into and out of the mitochondria
Inner membrane – compartmentalised into
numerous infoldings called cristae, which expand its
surface area thereby enhancing the ability to
produce ATP
Inter-membrane space
Matrix – fluid filled space enclosed by inner
membrane, contains enzymes which function on
the large surface area created by the cristae
Cristae
Reasons for varying numbers…
Variation in mitochondria number is related to energy requirement of the particular cell.
The higher the energy demand the greater the number of mitochondria.
• Low #s mitochondria = low respiration rate
– Plants (compared to animals): low metabolic rate so less respiration
required (producing unnecessary mitochondria would be a waste and lead
to lower ‘fitness’
– Bone cells require little ATP. Why?
• High #s mitochondria = high respiration rate
– Muscle cells: ATP needed for contraction, more mitochondria = more
respiration = more ATP = more movement = better able to carry out other
MRS GREN functions (catch food…)
– Sperm: ATP needed to make flagella move, so that…
– Glands: make lots of hormones, hormones are proteins and this requires
protein synthesis (requires ATP)…why are hormones needed?
– Liver: lots of enzymes to break down toxins (requires protein synthesis),
why?
– Cells lining small intestine: Take up glucose against concentration gradient
so need ATP…