Basic Concepts and Design
What is metabolism?
all the chemical reactions that take place in
series of energy transformations
Why do living organism require energy?
to synthesize large molecules from small ones
to move substances in and out of cells
muscle contraction and cell movement
What is the difference between phototrophs and
phototrophs obtain energy from sunlight
chemotrophs obtain energy from breaking
What is the difference between anabolic and
catabolic – fuels degraded to release useful
anabolic – energy used to synthesize
Why are reactions often coupled in metabolic pathways?
to insure that the overall free energy change is negative
a reaction that requires energy may be paired with
one that releases energy
2ADP + 2Pi
G°' = -184.5 kJ mol -1
2ATP + 2 H2 O G°' = +61.0 kJ mol -1
Glucose + 2ADP + 2Pi
2Lactate + 2ATP + 2 H2 O
G°' = -123.5 kJ mol -1
What is the role of ATP in cells?
donor of free energy in energy requiring
Why is ATP an energy rich molecule?
What are the factors that contribute to the
large amount of energy released when ATP
ease of hydration
What do we mean by
ability to donate a
besides ATP can
transfer PO4 groups?
How is ATP
regenerated in cells?
The oxidation of which of these two molecules
will produce more ATP and why?
How do molecules with high phosphoryl
transfer potential couple the oxidation of
carbon to the synthesis of ATP?
glyceraldehyde-3-PO4 + NAD+ + HPO4
1,3 biphosphoglycerate + NADH + H+
1,3 biphosphoglycerate + ADP 3phosphoglyceric acid + ATP
What is happening at
each stage of
While ATP is an activated carrier of
phosphoryl groups, what molecule(s) is
(are) activated carrier(s) of electrons during
nicotinamine adenine dinucleotide
flavin adenine dinucleotide (FAD)
+ H+ + 2 e -
One H is transferred to NAD with 2 electrons and
the other H goes into solution as a proton.
What activated carrier for electrons is used in most
biosynthetic reactions or the reaction shown
Why is coenzyme A an important molecule in
carrier of acyl groups
While metabolism consists of thousands of
reactions, each reaction falls into one of six
Group Transfer Reaction
Addition or Removal of
Regulation of Metabolism
What are the three basic ways in which metabolic
reactions are regulated?
controlling amount of enzyme
influencing rate of transcription
altering catalytic activity
controlling accessibility of substrates
Regulation of Metabolism
How do hormones influence metabolism?
alteration of enzyme activity
glucagon and glycogen phosphorylase
What other factors influence metabolism?
energy status of cell
What do ATP, NADH, FAD and coenzyme
A have in common and what does this
indicate about these molecules?
evolved from early RNA catalysts