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Unit 12: Lesson 1
Introduction to cellular respiration- ATP: Adenosine triphosphate
- ATP hydrolysis mechanism
- Cellular respiration introduction
- Oxidation and reduction review from biological point-of-view
- Oxidation and reduction in cellular respiration
- Introduction to cellular respiration and redox
- Introduction to cellular respiration
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ATP: Adenosine triphosphate
Learn more about ATP: how it stores energy, and how that energy is released when it's converted to ADP and phosphate. Created by Sal Khan.
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- please tell me about reducing sugars and whether sucrose is reducing or non reducing?(0 votes)
- Non-reducing sugars do not have an OH group attached to the anomeric carbon so they cannot reduce other compounds. All monosaccharides such as glucose are reducing sugars. A disaccharide can be a reducing sugar or a non-reducing sugar. Maltose and lactose are reducing sugars, while sucrose is a non-reducing sugar.(5 votes)
- Adenosine triphosphate and adenosine diphosphate are frequently mentioned. Is there an adenosine quadphosphate, or any adenosine with more than three phosphoral groups?(2 votes)
- Cells do contain polyphosphates that contain 4 or more phosphates connected via phosphoanhydride bonds. Technically, we also have Guanosine tetra phosphate (although the 4 phosphates are not all connected to each other).(3 votes)
- Just curious, can some animals photosynthesise or do plants only do that?(2 votes)
- so, just to be sure, there are only two high energy bonds in an ATP? (from) 2:14(2 votes)
- Correct, the bond between phosphoryl groups (known as a phosphoanhydride bond) is very high energy.
In contrast, the bond between a phosphoryl group and Adenosine is much lower in energy.
These reactions:ATP + H₂0 → ADP + Pᵢ
ADP + H₂0 → AMP + Pᵢ
yield more than twice the energy compared to this reaction:AMP + H₂0 → Adenosine + Pᵢ
(3 votes)
- Is combining with water the only way for ATP to turn into ADP and release energy for the cell to function?(2 votes)
- Dumb question: Adenosine triphosphate (ATP) has the prefix tri in it. Adenosine diphosphate (ADP) has di as the prefix. Why is DIphosphate used instead of BIphosphate (if bi means 2)?(1 vote)
- Di- is the Greek prefix for two. Bi- is the Latin prefix for two. Di- is generally preferred in the sciences as more scientific words are rooted in Greek.(4 votes)
- this video shows us that the reaction that change ATP into ADP relase some energy
the thing i'd like to ask is what is the form of this energy is it always in the form of heat?(2 votes)- It is chemical energy. However, energy transfer is not 100% efficient and some energy is lost as heat. (If I remember correctly, only about 35% of the energy from the breaking of the phosphate bonds of ATP is utilized by the cell - therefore, 65% of energy is released as heat.)(2 votes)
- So ATP converts into ADP and releases energy which we use. But where does the third phosphate group come from after you utilise the energy. In other words, how does ADP convert back to ATP. I can understand that as phosphate is phosphorus + oxygen (PO4), we receive oxygen as we breathe. But where do we receive the phosphorus from when we exercise and why do we need it?(2 votes)
- Most ATP comes from a process known as oxidative phosphorylation (https://www.khanacademy.org/science/biology/cellular-respiration-and-fermentation#oxidative-phosphorylation).
Oxygen is heavily involved in this process but its purpose is not to generate phosphate ions, but to act as what is called the "final electron acceptor" in a series of redox reactions that lead up to the biosynthesis of ATP.
Phosphate ions come from our diet. Dairy products are especially rich in phosphate.(2 votes)
- Can you tell me that if we use the energy to combine or i must say that if we react ATP and h20 together ito form ADP and energy. So can this process can be reversal too?(1 vote)
- Yes, it can and it is called phosphorylation which is basically adding a phosphate group to an ADP.(4 votes)
- Well, we generally know that bond breaking requires energy while bond forming releases energy. So, I still find this a bit confusing as to why would energy be released when ATP is broken to form ADP? Are there reactions other than this where bond is broken to release energy?(2 votes)
- You are right in that energy is used to break bonds, so when a strong phosphate bond is broken from ATP, a lot of energy was released. This is the form of energy that cells can actively use.(3 votes)
Video transcript
Sal: ATP or adenosine triposphate
is often referred to as the currency of energy, or
the energy store, adenosine, the energy store in biological systems. What I want to do in this video is get a better appreciation of why that is. Adenosine triposphate. At first this seems like
a fairly complicated term, adenosine triphosphate, and
even when we look at its molecular structure it seems
quite involved, but if we break it down into its constituent
parts it becomes a little bit more understandable and we'll
begin to appreciate why, how it is a store of energy
in biological systems. The first part is to break
down this molecule between the part that is adenosine
and the part that is the triphosphates, or
the three phosphoryl groups. The adenosine is this
part of the molecule, let me do it in that same color. This part right over here is adenosine, and it's an adenine connected to a ribose right over there, that's
the adenosine part. And then you have three phosphoryl groups, and when they break off they
can turn into a phosphate. The triphosphate part
you have, triphosphate, you have one phosphoryl
group, two phosphoryl groups, two phosphoryl groups and
three phosphoryl groups. One way that you can conceptualize
this molecule which will make it a little bit easier
to understand how it's a store of energy in biological systems
is to represent this whole adenosine group, let's just
represent that as an A. Actually let's make that an Ad. Then let's just show it bonded to the three phosphoryl groups. I'll make those with a P
and a circle around it. You can do it like that,
or sometimes you'll see it actually depicted, instead
of just drawing these straight horizontal lines
you'll see it depicted with essentially higher energy bonds. You'll see something like that to show that these bonds have a lot of energy. But I'll just do it this way
for the sake of this video. These are high energy bonds. What does that mean, what does that mean that these are high energy bonds? It means that the electrons
in this bond are in a high energy state, and if
somehow this bond could be broken these electrons are
going to go into a more comfortable state, into
a lower energy state. As they go from a higher
energy state into a lower, more comfortable energy state they
are going to release energy. One way to think about it
is if I'm in a plane and I'm about to jump out I'm
at a high energy state, I have a high potential energy. I just have to do a
little thing and I'm going to fall through, I'm going to fall down, and as I fall down I can release energy. There will be friction
with the air, or eventually when I hit the ground
that will release energy. I can compress a spring
or I can move a turbine, or who knows what I can do. But then when I'm sitting on my couch I'm in a low energy, I'm comfortable. It's not obvious how I could
go to a lower energy state. I guess I could fall asleep
or something like that. These metaphors break down at some point. That's one way to think
about what's going on here. The electrons in this bond,
if you can give them just the right circumstances they
can come out of that bond and go into a lower energy
state and release energy. One way to think about it, you start with ATP, adenosine triphosphate. And one possibility, you put
it in the presence of water and then hydrolysis will take
place, and what you're going to end up with is one of these things
are going to be essentially, one of these phosphoryl
groups are going to be popped off and turn into
a phosphate molecule. You're going to have
adenosine, since you don't have three phosphoryl
groups anymore, you're only going to have two phosphoryl
groups, you're going to have adenosine diphosphate,
often known as ADP. Let me write this down. This is ATP, this is ATP right over here. And this right over
here is ADP, di for two, two phosphoryl groups,
adenosine diphosphate. Then this one got plucked
off, this one gets plucked off or it pops off and it's
now bonded to the oxygen and one of the hydrogens
from the water molecule. Then you can have another hydrogen proton. The really important part of
this I have not drawn yet, the really important part of it, as the electrons in this
bond right over here go into a lower energy state they
are going to release energy. So plus, plus energy. Here, this side of the reaction, energy released, energy released. And this side of the interaction you see energy, energy stored. As you study biochemistry
you will see time and time again energy being used in
order to go from ADP and a phosphate to ATP, so
that stores the energy. You'll see that in things
like photosynthesis where you use light energy to essentially, eventually get to a point
where this P is put back on, using energy putting this P
back on to the ADP to get ATP. Then you'll see when biological
systems need to use energy that they'll use the ATP
and essentially hydrolysis will take place and they'll
release that energy. Sometimes that energy could
be used just to generate heat, and sometimes it can be
used to actually forward some other reaction or
change the confirmation of a protein somehow,
whatever might be the case.