Download ENERGY CURRENCY

ENERGY CURRENCY
BEGINS
Hello I’m Mr. Money. I’m here to inform
you about ATP, the energy currency in the
cell. You see, the cell operates a lot like a
money system. Here are some
comparisons:
•In the money system the currency used is the dollar.
How much work will you
do for $1 $!0 $!00? It’s
like a measurement of
your energy!
ATP- ADP + Pi + energy
ADP + Pi + energy  ATP
•In the cell system the currency used is the ATP
molecule.
•The dollar could describe energy or work done to
earn it and thus it represents stored energy.
• ATP needs energy to assemble it and thus also
represents stored energy..
•When a dollar is spent, it does not disappear, but
rather is recycled and used over and over.
• ATP, once used turns into the ADP molecule, but is
reassembled back into ATP. It also is used over and
over.
•The dollar is the currency used throughout the country
for all money transactions.
•ATP is the energy molecule used by all eukaryote and
prokaryote cells in all their cellular energy transactions.
ATP is a short form representing the
chemical Adenosine TriPhosphate.
ATP is used in cells for the following
work:
Mechanical work – ex cilia
beating, muscle contraction
When exposed to
the flame I turn
blue green. You’ll
find me on the
adenine scene.
Element Phosphate
•Transport work – pumping
substances across membranes
•Chemical work – use of energy in
biosynthesis of endergonic
reactions
Well, there it is, the ATP molecule. Notice it has three
phosphate molecules. The bonds between these phosphates
release energy when broken.
The bonds between the phosphates are unstable and can be broken by hydrolysis. When
water hydrolyzes the terminal phosphate bond, the molecule turns into ADP, phosphate
Pi(inorganic) and -7.3 kcal of energy.
This means ∆G = -7.3 kcal/mole for the following reaction (-ve means energy release)
ATP + H2O  ADP + Pi(inorganic)
ATP bonds can release a lot of energy, but they actually are WEAK or
UNSTABLE BONDS that are easily broken. Remember, each phosphate is
negative, so each repels each other. ADP is thus more stable because it has
less negative phosphates in the row repelling each other.
I want you to notice something else about this molecule. Notice
that it has three phosphates in a row with negative charges.
These charges should naturally repel each other. Since they are
together they store energy like a tightened spring
So the high energy phosphate bond is actually not high
because of a strong bond between phosphates, but
rather high in energy because of the resultant release of
energy due to hydrolysis of the terminal phosphate.
Remember I
taught you about
exergonic and
endergonic
reactions!
To the left, the diagram shows the ADP and Pi. This
molecule can be reassembled back into ATP, but energy
is required in order to do this. Thus an exergonic
reactiion must first release energy. Catabolic pathways
like cellular respiration provide this energy. Then the
energy is used to power the endergonic reaction that
ultimately makes the ATP molecule that stores energy.
ADP + Pi + 7.3 kcal  ATP + H2O
∆G = + 7.3 kcal/mol
Photosynthesis can also use light energy to
provide the energy necessary to make ATP.
Hi there I’m ATP and I would like to inform you that I often can change
due to the fact I can lose phosphates when I release ENERGY!
If I lose one phosphate, I become ADP
adenosine di phosphate. I often will cycle
back to ATP in the energy exchange process
and this is the most common usage.
Cyclic AMP.......!
I can also lose two phosphates and turn into
AMP adenosine mono phosphate. Now this
also can be cycled back to ATP, but there is a
function of AMP. Specifically cAMP or cyclic
AMP is involved in intercellular signalling,
especially when you add adrenaline or
glucagon to the body!
Worm
tackle
fishing
for
info
GETIT?
I have a problem I want all you keen biology
students to tackle.
Glutamic acid plus ammonia can be converted into the
amino acid glutamine. The change in free energy, your so
called “Δ G “ is + 3.4 kcal /mol
Can hydrolysis of ATP provide the energy to get this done?
Not sure are you my courageous caped crusader crimefighter! You need genius me to walk you through it.
Hydrolysis of ATP yields -7.3 kcal/mol
Now I’ve given away the worm. You probably now
can tell that if you couple these reactions you will...
Have enough energy to produce the glutamine!!
If you still don’t get it, think about how you need to provide 3.4 kcal/ mole of
energy and the hydrolysis of ATP yields 7.4 kcal/mol. That’s more than enough
energy to power the reaction!
Before I move on I would like to introduce all of the
energy molecules we will be dealing with.
1. ATP – PRIMARY ENERGY CURRENCY
2.NADH- Reduced form of NAD acts to store energy
as it carries an electron. Used in cellular metabolism
– is a coenzyme derived from vitamin B3 niacin
3.FADH2- Reduced form of FAD acts to store energy
as it carries an electron. Used in cellular metabolism
It is a coenzyme derived from vitamin B2 riboflavin
4.NADPH Reduced form of NADP acts to store
energy as it carries an electron in photosynthesis.
5.GTP -- high energy molecule with phosphate
bonds like those of ATP – can be changed into ATP.
Hey girlie man. You better remember what I
taught you or I will take your puny head with your
little weak neck muscles and make the toilet seat
your best friend!
Glutamic acid is
ionic electrically
charged
Glutamine is
polar
Now tell me this... is this glutamic acid
polar ionic or non-polar? Don’t tell
me you forget or you will suffer worse
than Coli-for-ni-a.
How about this one. What is this
glutamine? Polar, ionic or non-polar?
And yes you were supposed to
memorize the chart that indicated
this. You should not question the
man of steel biceps!!
Uh oh. Now I’ve done it! I have dropped
you into freezing cold water!
I can watch as your body attempt to maintain its
temperature by the action of your muscles
shivering!. Poor courageous caped crusader, you
will be hydrolyzing ATP to generate heat. Each ATP
will release it’s -7.3 kcal/mol into the surrounding
tissues simply as heat. What a waste of energee!
Rather inefficient use of the ATP wouldn’t you
agree. But of course you can’t answer, you’re
freezing to death by hypothermee!!
Here’s a riddle for you now. What stage of hypothermia are you in. There are
three, and if you pick correctly, you get to come out instantly!
So you say stage 2. Well there’s your canoe!
Riddle me this.
What do ATP, DNA, and RNA share in common?
They all contain ADENINE!! Both ATP and
RNA contain adenine in form of Adenosine
MonoPhosphate ( AMP is a nucleoside).
ATP has an additional two phosphate
groups added.
ATP can be made in different ways. It can
be made by substrate phosphorylation or
it can be made by oxidative
phosphorylation. In plants it is also made
by photophosphorylaton
This is an example of
substrate level
phosphorylation where ATP
is made in the cytoplasm of
cells with the aid of enzymes
Photophosphorylation
Oxidative
generates ATP in the
phosphorylation
chloroplast of plant
generates ATP via
cells.
chemiosmosis in the
mitochondrion
DID YOU KNOW?
One muscle cell can
consume and regenerate
over 10,000,000 ATP's a
second.
If we did not regenerate and reuse
ATP we would consume our body
weight in ATP each day.
ATP can release energy if hydrolyzed, but the
energy can be more effectively captured by
transferring a phosphate to some other
molecule. This molecule is phosphorylated and
is more unstable than the original molecule.
The formation of phosphorylated intermediates
is common in nearly all cellular work.
Glutamic acid + Ammonia -Glutamine ∆G =+3.4 kcal/mol
This reaction is non spontaneous because of the positive ∆G
With the assistance of ATP and the formation of intermediates, this
reaction can be made to occur spontaneously as shown by the net ∆G
Glutamic acid + ATP  Glutamic –P + ADP
Glutamic—P + Ammonia  Glutamine + P
∆G = + 3.4 kcal/mol
∆G = -7.3 kcal/mol
Net ∆G = -3.9 kcal/mol
Now I’d like you to meet NADH, another
energy currency. NADH is worth 3 ATP , but in
order for it to be utilized, it first must be
converted into ATP. In order for this
conversion to occur, oxidative pathways must
be available.
NAD+ is nicotinamide adenine dinucleotide and is found in all cells. It is
actually classified as a coenzyme . In its reduced high energy form it is
officially NADH + H+. (In this discussion, it will be understood that NADH
represents NADH + H+.) NAD+ acts as an oxidizing agent and can remove a
pair of electrons (and protons H+) from a substrate. These two electrons
along with one proton attach to the NAD+ to form NADH. The other proton is
released as a hydrogen ion (H+) forming NADH + H+.
An example of this is shown below where X represents the substrate that is oxidized.
XH2 + NAD+ -- X + NADH + H+.
Now I’d like you to meet FADH2.
FADH2 is only worth 2 ATP , but in order
for it to be utilized, it first must be
converted into ATP. In order for this
conversion to occur, oxidative pathways
must be available.
FAD is flavin adenine dinucleotide which is a coenzyme in metabolic
pathways. The FAD is used as an oxidizing agent and will accept two
hydrogen atoms from a substrate to produce the high energy FADH2.
An example of this is shown below where X represents the substrate that is
oxidized.
XH2 + FAD -- X + FADH2.
FAD actually only has one nucleotide even though the name
says dinucleotide. Who would have thought?
FAD is derived from vitamin B2 Riboflavin - there’s the
flavin. I’m just flavin like flavor flav
Here are the
two main
methods of
generating
the ATP
molecule.
SUBSTRATE LEVEL
PHOSPHORYLATION OF ATP
ATP can be generated by
substrate level phosphorylation.
You can see the enzyme action
and the assemble of the ATP
molecule shown on the side. All
cells are capable of this type of
ATP synthesis.
CHEMIOSMOSIS GENERATION OF ATP
ATP can also be generated by a protein
membrane complex coupled to the ATP
synthase. Hydrogen ions are locked in a
membrane and as they attempt to reach
equal numbers both inside and outside
OSMOSIS they pass through ATP synthase and
generate ATP from ADP and Pi.
Another energy molecule is NADPH.
This is simply a variant on NADH
where phosphate has been added. It
is restricted to use in the
photosynthetic pathways .
NADP+ is nicotinamide
adenine dinucleotide
phosphate and is reduced
into the higher energy
NADPH. NADPH is used in
biosynthesis of organic
molecules in the Calvin cycle.
Not the
Pontiac
GTP!
GTP is another energy molecule and it is similar to
ATP. It utilizes the nitrogen base guanine rather than
adenine, but otherwise the molecule is basically the
same. It has the same three phosphates attached
that produce the high energy phosphates bonds
which when hydrolyzed.
I’m Dr. Krebs. You’ll see
my cycle soon!
Translation of
proteins from RNA
GTP can be converted into ATP (This is done in the Krebs cycle)
GTP is used specifically in protein synthesis as an energy
source. It acts like ATP, but is more specific.
GTP is essential to signal conduction inside of cells where it acts as a
second messenger to cause the activation of metabolic pathways. GTP
converts to GDP+ Pi much the same as the ATP hydrolysis reaction.
Riddle me this or you
lose Mr. Money!
I once had a charge, but now I am neutral. I’ve
gained two e’s but just one p. What am I?
I’m NADH
I disguise as Dan only inverse and I don’t leave
home without my sceptre. I am your green
solution, just like environmentalists adore.
Just Try to figure out who I am. You’ll
never see me take out an AD.......
I’m NADPH
I’m ATP
Time for me to take
away the MONEY. Mr.
Money is mine now!
HELP!!
Hi there. Remember me, I’m the ATP molecule. I want
you to slow down for a minute and ponder something
special. I want you to look at the big picture of these
energy molecules. You see, they all seem to have
something in common. They all have purine ( Adenine
or guanine) nitrogen bases attached to sugars and
phosphates.
You might just think this is some sort of coincidence, but maybe it
is not. Maybe it relates to a much bigger concept. The metabolic
pathways we will study are common to virtually all living things.
This connects all life on the planet together......together to a
common ancestral origin. Why is there this common thread of
the chemicals of metabolism?...I submit the answer is evolution.
The creation of the first living cells! I have discovered the secret. I
have CREATED LIFE!!!!
Come see me as soon as you can in my presentation of the first cells. I
guarantee you will understand so much more about our world!!
Now I understand that your background in evolution
may not be very strong, so bear with me. Evolution
is integral to understanding the living things we see
today and understanding how they came to be. Lets
take a look again at our energy molecules.
ATP and NADH are present in all known forms
of life forming a core part of metabolism and
indicating that these molecules evolved very
early in the development of living things At
least some of the current set of cofactors may
therefore have been present in an ancestor ,
that lived about 4 billion years ago. ( The earth was
formed 4.5 billion years ago)
Now here is the leap. Evidence seems to
point to these molecules pre-dating even the
first cells. The Theory that is gaining support
is that of the RNA world. The RNA molecule
can act as both an enzyme and an information
molecule. RNA in this theory predates the
DNA directed living world we see today.
The RNA evolved into the more stable DNA
world of today, but the remnants of these
early pathways persist in all our cells. Take it
away Inspector Clouseau.
Facts, students, facts! Nothing matters but the
facts. Without them the science of investigation
is nothing more than a guessing game.
Facts, dear
students, facts,
behind them
lays the whole
fabric of
deductive
truth. Now,
students let us
examine these
facts: 1
1. FACT ---the nucleotide ADENOSINE is present in cofactors
that catalyze many basic metabolic reactions such as methyl,
acyl, and phosphoryl group transfer, as well as REDOX
reactions.ie ATP NADH FADH2...
2. FACT –nucleotide ADENOSINE is the building block to
assemble the RNA informational molecular chain, it has the
nitrogen base, sugar, and phosphate in the correct bonding
arrangement.
3. FACT – RNA can act to catalyze a chemical reaction -- called a
ribozyme
Now then, Mr.
ATP , tell the
students what
these facts add
up to?
4. FACT--- in ribosomes (made of RNA +protein) the RNA
adenosine site is the active site (not the protein) that catalyzes
the peptide bonds to make amino acid chains( proteins). RNA
here is a ribozyme
5.FACT—RNA can catalyze its own synthesis – it can make itself
from chemical reactions it catalyzes.
Well those facts seem to point to the RNA as being the
earliest information storing molecules that most likely
were also capable of generating the first protein
molecules. These are the basic tasks of the DNA
molecule of today.
But the
facts??
??????
?????
You are an idiot, only a fresh faced novice would come up
with a conclusion like that.
Listen, you are forgetting the most important fact– instinct
My instinct tells me that the molecule that started all this is
still not settled. What is happening here is an attempt to lay
the blame at the foot of this, this poor RNA molecule.
Inspector, the RNA world hypothesis places RNA at center-stage
when life originated. This has been accompanied by many studies
in the last ten years demonstrating important aspects of RNA
function that were not previously known, and support the idea of a
critical role for RNA in the functionality of life. You will also want to
know that we have located the Riddler.
I arrest you in
the name of
the leahw!
So that’s the way it’s gonna be! Purine
metabolism molecules surrounding me!! You
think that can stop me? I think NOT!
NAD
It’s over
Riddler!
Don’t make
me have to
reduce
myself to
NADPH !
NADP
That’s right,
my reduced
form FADH2
has very high
energy!
Hey, he is so witty.
We all have purine
bases. What a waste
of intelligence.
GTP
ATP
You don’t
want to see
me when I
am reduced
to NADH!
FAD
Lets take this walking green
piece of scum to jail boys!
Good work my
little crimefighturs.
I’m innocent. I
didn’t do nothin’.
You can’t prove I
did nothin’!!
Did you say Crime
fighturs? That’s wrong,
it’s crime fighters.
That is what I said you
ignorant jail-bird. My
crime-fighturs have
captur-ed you! He is
one to talk with his slang
usage of the language.
Hey thanks for the
rescue. See you
soon!
End Energy
Molecules