- [Voiceover] All that energy used
has to come from somewhere.
So where do you get your energy?
You've several different sources to obtain energy.
Fats are one source.
Now I'm not just gonna go out and eat a stick of butter
or something, that's just not right but
you have fats in the food you eat.
These triglycerides are long-term energy.
They won't give you a fast boost of energy
or a quick high.
What they do is, if you're working out for a long period,
or you have a long period between meals,
these'll help keep your body running for the long haul.
Glycogen.
Whenever you eat any carbohydrates,
so think about breads or pastas,
you'll store some of the carbohydrate you do not use.
These stored carbohydrates are stored
in the form of glycogen, a very large carbohydrate molecule.
But carbohydrates are meant for short-term.
These reserve fuel source,
these back-up sources are used first.
They're used for that quick burst of energy.
So, glycogen.
Now that cell structure we mentioned,
about the whole cytoskeleton before,
already said the cytoskeleton is for structure and support.
But that's not the only thing.
The cytoskeleton not only gives structure to your cell,
it helps support the organelles inside,
keeping the organelles in proper placement.
Cilia, well cilia are tiny, hair-like projections.
I put short and many.
So you can kinda think of cilia
as these tiny little hair-like projections.
So if someone has a buzz cut for instance,
a lot of tiny little hair cells coming off.
Now cilia aren't really hair, but they act similar.
The fluid around the cell can cause the cilia,
these tiny hairs, to move back and forth.
Flagella, well that's one long, single protrusion.
So a cell that has a flagella is a sperm cell, for example.
The tail of the sperm is a flagella.
It's meant to help with propulsion of that cell,
moving that cell through a fluid.
Centrioles.
Well, centrioles are aiding with the cell division.
They help that one cell split into two different cells.
Now there are two main processes that will deal
with the use and transformation of matter and energy.
The first one is an anabolism.
In anabolism, you have to use enzymes.
These enzymes are going to make or assemble large molecules.
So, take a whole bunch of small building blocks,
put 'em together, and build a larger molecule.
Now I have up here it may require energy.
More often than not, anabolism is gonna need energy
to build the bonds.
It's going to need energy to put molecules together.
So anabolism, you're creating, or making, larger molecules.
Well, the flip side, catabolism.
Catabolism is also requiring enzymes,
but now you're breaking down molecules.
In catabolism, a lot of times when you break down molecules,
you break that bond, the breaking of the bond
will release energy.
So both require enzymes, so what is an enzyme?
An enzyme is a molecule that facilitates
or helps a chemical reaction along.
So enzymes can be used over and over and over
for their specific chemical reaction.
Enzymes are always specific.
But in the case of anabolism,
you're building or making a larger molecule.
Catabolism, you're breaking it down,
making a smaller molecule.
So what you're building, more often than not,
you're putting energy in to make that bond.
Catabolism, when you break the molecule down,
more often than not, you're getting energy,
or releasing energy from the broken bond.
So, all this energy I keep talking about,
well where is the energy, what is it?
Energy is produced from the food you eat.
The main source of energy of the body is the sugar glucose.
Glucose is a simple sugar, or a monosaccharide.
The glucose molecule is how your body
primarily generates ATP.
Remember ATP is the actual energy source the cells can use.
But if don't have glucose, you can use other things.
Other carbohydrates can be used like fructose or lactose.
You can use fats, triglycerides.
And proteins can also be used.
But what's happening here now,
is they're all being catabolized,
or going through the process of catabolism.
When you go through catabolism,
you take the molecule, break the bond to release energy.
Well, that's great, no problem.
Except we got a little issue.
Protein.
What do proteins make up?
Muscles, bones, a lot of your organs.
Is it a good idea to use protein then,
to make energy?
See, you break down your muscles to provide energy.
It could save your life, could help you live longer,
but it's not the smartest thing to depend on.
Fats, carbohydrates, thankfully are used first.
So, glucose is the primary,
but if it can't work,
you go into other carbs, you go into fats,
you go into proteins.
Here we're seeing a basic diagram
of how the cell is obtaining energy,
and then using energy.
To produce the energy in the first place,
you go through what's called cell respiration.
It's a process that ultimately goes through a couple steps,
but you start with glucose and oxygen.
You then head through these processes of cell respiration,
you end up with carbon dioxide and water as a waste product.
Well, by doing all that,
by producing those molecules
and going through those reactions, you're producing ATP.
You can take 36 ADP, adenosine diphosphates,
and at 36 phosphates on it.
That way you get 36 adenosine triphosphates.
So during cell respiration, you're breaking bonds down,
releasing energy, which then puts energy
into that middle circle here,
to form bonds from ADP and phosphate.
You can then take that ATP,
which is to release energy.
So, you break off one phosphate, release the energy,
that performs cellular work.
Could be anabolism, could be transport,
muscle contraction.
There's a whole bunch of things that could occur
via the use of ATP.
So we see here a mitochondria blown up.
The mitochondria is in the background of the green,
the blue, and purple structures here.
The orange is outside.
So if we start with the orange,
the process known as glycolysis.
Glycolysis is the first step in cell respiration.
It will take the glucose in, make a couple ATP,
and provide a product.
That product is put into the mitochondria.
Once in the mitochondria, you kinda prep it, get it ready,
and it goes into the citric acid cycle.
The citric acid cycle heads down
to the electron transport system.
SO really there's three primary steps here.
Glycolysis, you produce a couple ATP.
The citric acid cycle, also known as the Krebs cycle,
produces even more ATP
and then you go into the electron transport system.
The electron transport system is the main producer of ATP.
It produces the vast majority of ATP
from the mitochondria.
So, let's look at a little more detail.
We start off, glycolysis.
Glucose goes to pyruvate.
That's the product there.
So what happens is,
you initially have to use two ATP molecules
to start the process, get everything going.
Well, once you're going you're gonna end up producing
a total of four ATP molecules.
All right, no big problem.
So far, so good.
We then go into that prep step,
which helps produce two acetyl CoA molecules.
These two acetyl CoA molecules
are sent into the citric acid cycle
or also known as the Krebs cycle.
Again, not a lot of ATP production,
but you still get two more.
You take that citric acid cycle,
put those products into electron transport chain
and by going through a process
called oxidative phosphorylation.
Now, not that I'm worried if you don't remember that,
but the key thing is you're going through
and moving this electron transport chain.
Produces about 34 ATP.
So you take all the numbers, add 'em all up,
give or take you're about 36 ATP molecules.
So 36 molecules of energy produced,
for each individual glucose molecule.
So by going through all these steps it's pretty efficient
at making energy from glucose,
as long as you have oxygen available.
The electron transport chain, you see,
needs oxygens to enter.
Without oxygen that system does not run.
At the very end you can see there's two ATP kinda shell here
helping with the electrons.
The idea is all of this energy is being reused.
Nothing's going to waste.
But where do you get extra energy from.
Mentioned the term glycogen before.
Remember by chance, what glycogen is?
Glycogen is your reserve fuel,
your reserve storage of carbohydrates.
You have fats as an additional source.
Triglycerides have, if not twice,
almost pushing two and a half times,
the energy of carbohydrates.
The only problem is, fats are slower release.
Carbohydrates, like glycogen, is a faster release of energy.
Proteins can also work at about the same energy
as your carbohydrates, so same as glycogen.
But you really don't want to break down too many proteins.
Remember proteins are structural.
They're what make your muscles.
They help with the bones, the organs.
So, it's not a good idea to break down a ton of protein.
But unfortunately sometimes our system
is in an anaerobic process.
Now anaerobic is without oxygen.
This can occur if you're working out
and you're really pushing yourself.
You're above that 70% mark.
So you have, let's say your maximum workout is 100%,
if you do at least 70% of that ability
you start to lose some oxygen saturation in your muscles.
Your muscles can't quite get enough oxygen in.
So what happens?
Well, glucose is still turned into pyruvate
via glycolysis,
but the problem is that pyruvate
is now turning to lactic acid,
because there's no oxygen present.
Now if you've ever heard of lactic acid before,
you have heard lactic acid, workouts, burning muscles.
Lactic acid is the fluid, the liquid,
that can end up building up in the muscles,
causing that burning sensation
when there's not enough oxygen.
Because anaerobic, or without oxygen,
nothing in the mitochondria can run.