Role of ATP and NAD
H2.2.8
Syllabus Objectives
• Explain the role of ATP and describe how it is
formed from ADP + P
• Explain the role of NADP+ in trapping and
transferring electrons and hydrogen ions in cell
activities
Energy Carriers
• ATP , NADP+ and NAD+ play a vital role in
trapping and transferring energy in cellular
activities
ADP and ATP
• ADP is an abbreviation for Adenosine
Diphosphate this is a molecule found in the cells
of all organisms
• It is made of the base adenine , a 5 carbon sugar
called ribose and 2 phosphate groups
• ADP is a low energy molecule
ADP and ATP
• If another phosphate is added to ADP it forms
ATP (Adenosine Triphosphate)
• Extra energy is also added as there is an extra
bond between the last two phosphate groups
• Addition of a phosphate like this is called
Phosphorylation
• ATP is rich in energy and stores this energy
carrying it around in the cell
ADP and ATP
• ATP cannot store energy for very long it breaks
down releasing energy and converting back to
ADP
• Most cells release energy from ATP 10 million
times every second! This energy is used for
cellular reactions
Learning Check
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What do ADP and ATP stand for?
What base is found in ATP and ADP?
What sugar is found in ATP and ADP?
Which is a higher energy molecule?
How does ADP become ATP?
This process is called p..................................
How is the energy in ATP released?
NADP+ and NADPH
• NADP+ is a low energy molecule involved in
photosynthesis
• NADP+ can combine with 2 high energy
electrons and a proton to form NADPH
• NADPH is a very high energy molecule
• It’s energy is used to form glucose in
photosynthesis
NADP+ and NAD
• NAD+ is used in respiration
• It can combine with 2 high energy electrons and
a proton to form NADH which is very high in
energy
• Remember P for photosynthesis, NADP+ is used
in photosynthesis NAD+ in respiration
• Both NADH and NADPH release energy and
protons when they break down into NAD+ and
NADP+
• These electrons, protons and energy are used by
cells
Learning Check
• Is NADP+ used in photosynthesis or
respiration?
• What combines with NAD+ and NADP+ to form
NADH and NADPH?
• What do NADH and NADPH provide for
reactions in cells?
• How do they provide these things?
END