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Cell Energy Molecules
Chapter 5
What you need to know!
• How the process of chemiosmosis utilizes
the electrons from NADH and FADH2 to
produce ATP
• How linear electron flow in the light
reactions results in the formation of ATP,
NADPH, and O2
• How chemiosmosis generates ATP in the
light reactions
Energy Transfer Molecules
ATP: Adenosine Triphosphate
• Molecule that delivers immediately
available energy to run cellular processes
(active transport, movement, mitosis,
production of proteins etc.)
• All other food/energy molecules (various
lipids, carbs, proteins) are converted into
ATP through enzyme machinery in
cells/liver
• All energy consuming processes have an
ATPase (enzyme) attached
Energy Transfer Molecules
• ATP is a nucleic acid, a single nucleotide
Energy Transfer Molecules
• ATP has energy stored between its three
negatively charged phosphates because
like charges repel each other
• Most energy is stored between 2nd and 3rd
phosphate
• 3 different forms of energy levels:
– AMP: monophosphate
– ADP: diphosphate
– ATP: triphosphate
Forming ATP for Energy Supply
• Rx: ADP + P + energy  ATP
• Enzyme: ATP synthase
• Energy necessary comes from
photosynthesis or respiration
Breaking Down ATP for Energy
Release
• Rx: ATP  ADP + P + energy
• Enzyme: ATPase often attached as a
coenzyme to various other
enzymes/proteins
ATP Resembles a Rechargeable
Battery
• Endlessly recyclable
• Limited numbers of ATP/ADP can stop
energy pathways
• Largest amount of ATP is made in
mitochondria/chloroplasts some in
cytoplasm (glycolysis)
• All energy molecules can be expressed in
ATP (glucose: 36 ATP, sucrose: 75 ATP,
triglyceride: 180 ATP; assuming O2 is
present)
Energy Availability
Molecule
availability
storage
ATP
immediately
none
glucose
1-2 min
Blood glucose
only
glycogen
2-3 min
Liver, muscles
triglycerides
8-10 min
Adipose tissue
NADP/NAD/FAD
• Nicotinamide Adenine Dinucleotide
Phosphate (NADP)
• NADP Functions as electron
acceptor/donor during photosynthesis and
respiration
• NAD & FAD work the same way
• A nucleic acid: dinucleotide
Rx:
Rx:
Store Energy
NADP + e- + H+  NADPH
Release Energy
NADPH  NADP + e- + H+
Summary
Sample Questions
1.
Which one of the following is true about the ATP molecule?
a) It contains two phosphate groups.
b) Extremely stable bonds link the second and third
phosphate groups
c) It contains the six-carbon sugar hexose
d) It contains a nitrogenous base molecule called adenine
e) None of the choices are correct
2.
ATP can be used as the cell’s energy currency because
a) Cellular functions can be fueled by coupling them with
the formation of ATP from ADP.
b) ATP is the most energy-rich small molecule in the cell.
c) Cellular functions can be fueled by coupling them with
the breakdown of ATP to ADP.
d) All of the above are true.
e) None of the choices are correct.