3.4 Food as Fuel Flashcards
NADH
The reduced form of the coenzyme nicotinamide adenine dinucleotide
Dehydrogenase
An enzyme that oxidizes a substrate and transfers hydrogen ions to an acceptor
What do gasoline and glucose have
in common?
- Both have an abundance of
Carbon-Hydrogen Bonds
-These bonds hold a large amount
of Potential Energy
Electrons and C-H bonds
The farther away an electron is from the
nucleus of an atom the MORE
POTENTIAL ENERGY IT HAS
- Energy is released as electrons move
closer to the nucleus - Energy is absorbed as electrons move
farther away from the nucleus
How is Energy Released?
As the electrons in the C-H bonds are pulled
toward larger, more electronegative nuclei
(from other atoms) ENERGY is released as the
electrons move to a lower energy level.
Ex. Oxygen atoms are very electronegative and
will pull the electrons closer towards their
nuclei. As they do so the electrons release
energy.
Rapid Combustion and Controlled Oxidation
The example just mentioned results in rapid
combustion which would be disastrous for
living organisms (we would spontaneously
combust!)
- Reactions within the body need to be
controlled and so undergo a number of
different steps
- The body can STORE ENERGY at each step
and increase the efficiency of the reaction
(so we release less wasted heat energy)
Energy Changes during Redox Reactions
- Oxidation occurs when an atom or
molecule LOSES ELECTRONS to another
atom - Reduction occurs when an atom or
molecule GAINS ELECTRONS from another
atom - As electrons are exchanged they may be
shared in different arrangements which
results in the release of energy
Energy Carriers
Molecules that help to store energy
released by reactions
Help to power other reactions
Also called Dehydrogenases – help remove
hydrogen atoms and transfer electrons
Ex. NAD+ is reduced (gains 2 electrons and a
Hydrogen) to form NADH. NADH can be used
to power ATP synthesis
Reduction of NAD+
NAD+ 2e- + H+ –> NADH
