Download Cellular Metabolism

Cellular Metabolism
ATP: adenosine
triphosphate
ADP: adenosine
diphosphate
- product of ATP
• ADP + P + O + Energy = ATP
Anabolism
ATP = ADP + P + O + Energy
Catabolism
• ATP is synthesized by adding a
phosphate group (Pi), to ADP.
Energy is required to form this
high-energy bond. When ATP
is used in a chemical reaction,
the energy released and made
available to cells to do work.
• ATP is a specific nucleotide. What
makes ATP different from other
nucleotides such as cytosine,
thymine, guanine, and adenine, is
that it is used widely as a carrier of
chemical energy. ATP is adenine with
three phosphate groups attached.
The bond connecting the phosphate
molecules to adenine are highly
energetic bonds.
• Locate this in your lab book.
• Two of the phosphate groups, which
are easily broken down to release
energy, are added in a covalent bond
during processes such as respiration.
ATP is used to drive active transport,
and other chemical reactions such as
photosynthesis, and cellular
respiration.
• ATP is broken down by hydrolysis
(reaction with water), which yields
adenosine diphosphate (ADP),
inorganic phosphorous, and
energy.
ADP/ATP Cycle
Catabolic Processes
• metabolic process that breaks down
molecules into smaller units
Catabolic Processes
• Glycolysis: the breakdown of glucose to
pyruvic acid in the cytoplasm of the cell;
it’s the oxidation of glucose.
-anaerobic: does not require oxygen
-this reaction provides:
+2 ATP molecules
+2 pyruvic acid molecules
-not an efficient method
• This anaerobic process of glycolysis
enables the cell to continue generating
ATP when the mitochondrial activity alone
cannot meet demand.
• Not efficient because the mitochondria can
produce 18 X more ATP per single glucose
molecule. Lots of energy is still locked
away inside the pyruvic acid molecules.
The only way to get it is with the use of
oxygen.
Glycolysis
• http://www.science.smith.edu/departments
/Biology/Bio231/glycolysis.html
Krebs Cycle
• AKA: TCA Cycle, citric acid cycle
• Occurs inside the mitochondria, removes
hydrogen atoms from organic molecules
and transfers them to coenzymes.
• The electrons in these hydrogen atoms
contain energy that can be used by the
mitochondria to generate ATP.
• A complete revolution of the TCA cycle
removes the two added carbon atoms,
regenerating the four-carbon chain. The
two removed carbon atoms generate two
molecules of CO2, a waste product. The
hydrogen atoms are removed by
coenzymes and delivered to the electron
transport chain.
• Occurs in the mitochondria
• Removes two carbon atoms due to
coenzymes
• Hydrogen atoms are delivered to the ETC
to generate ATP
• The only immediate value of the TCA cycle
is an immediate ATP molecule. The real
value in this cycle is the fact they deliver H
atoms to the ETC.
Electron Transport Chain
Coenzymes in the mitochondria matrix
deliver hydrogen atoms to the electron
transport chain; the electrons are removed
and passed from cytochrome to
cytochrome, losing energy in a series of
small steps.
Most important mechanism for the
generation of ATP (provides 95%)
• At the end of the ETS, an oxygen atom
accepts the electrons, creating an oxygen
ion (O2-). This ion is very active, and
quickly combines with Hydrogen ions (H+)
to form a water molecule.
• Fore each glucose molecule broken down
32 molecules of ATP will be generated.