first class off
our proteins and the proteins are
obtained from the amino acid monomers
and let's look at these I'm gonna amino
acids in closer let's take for example
this amino acids alright this is an
amino acid this is the carboxylic group
right and this is the amine part this is
simple hydrogen and that is the alkyl
group
it could be hydrogen or I'll kill any
alkyl groups here again as you see if
this R is not equal to the hydrogen
which is a glycine the simplest amino
acids the amino acids are optically
active there must be chiral why because
we have a carbon and to this carbon four
different bonds group actually bonded to
that carbon means make that amino acid
optically active actually optically
active
now these chiral molecules and these
enantiomers one we said rotates the
plane polarized light to the left
certain angle the other one rotates a
plane polarized right to the right
certain angle and so the one which
rotates to the right is termed by simply
D the one which rotates to the left is
called L so the optically active or
chiral molecule enantiomers one of the
energy members is called
deform the capital D actually I should
say deform or al form and L is the one
rotates the plane polarized light to the
left D is the one rotates plane
polarized right to the right right we
have two
that again so that means that amino
acids will have a D and al for now the
interesting things again all amino acids
in living organisms are al for only
there are few but bacteria have the D
form of the amino acids very few
actually but all of them are al form not
the D form how for one enantiomer is a
matter of fact okay
now let's look at this again this is the
this is the let me write it down
carboxylic acid carboxylic acid part and
this is the amine group and this is
simply the alkyl group
it could be alkyl or other group in fact
alkyl or other groups again and this
carbon which is next to the carboxylic
acid carbonyl carbon is called alpha
carbon this is called simply alpha
carbon carbon and this amino acids which
has the amine group attached to the
Alpha carbon are called
alpha amino acids alpha amino acids all
four amino acids now when we simply
polymerize this amino acids by peptide
link it's actually condensation
polymerization by giving one water
molecule out and forming another carbon
simply nitrogen bond which we call that
peptide bond we end up with proteins
proteins now again how big these
proteins there
Fareway very large very big molecules
the average again I can't say exactly
but the molecular weights like five
hundred thousand atomic mass units
sometimes million atomic mass units and
so on very large big molecules now there
are again twenty-two amino acids I guess
has to be twenty-two over here one two
three four five six seven eight nine 10
11 12 13 14 15 16 18 19 20 here we have
20 only 20 of those are found in human
bodies again 20 of those but we have to
remember that out of those 20 amino
acids we can only synthesize our body
can only synthesize 11 of those so that
means that nine of the amino acids which
we need have to be taken by food eaten
the food that means they have to be
ingested right ingested that's another I
guess important things interesting too
now the amino acids are simply combined
by peptide links as we say here and form
the polymers and the proteins let's read
this slide here again amino acids have
amino and carboxylic acid functional
groups as we see here amino and the
carboxylic acid functional groups
proteins are polymers of alpha amino
acids again alpha means the amine is
bonded to the second carbon from this
side here a condensation reaction
between the amine end of one amino acid
and the acid end of another produces the
peptide bond and this is called peptide
link or peptide bond which is an amide
linkage okay let's
to simply look at this and see how we
can get the peptide lane now
the amino acid this amino acids is also
found in this form to this part is
acidic part right this is the acid and
remember a mean is the basic part it has
that electron pair which makes it loose
base and can accept the protons and the
amino acids can be found in this form to
this amino acids are and here is co all
- and hydrogen and here we have nh3 plus
the ionic form of the amino acids this
is simply called sua turian iron again
right so that hydrogen can be here or
can be there as a matter of fact so this
is the ionic form of the amino acids
amino acids let's look at again how we
form the peptide linkage peptide bond
okay let's take this amino acids the
ionic form and this is actually glycine
simplest amino acid glycine this is the
hydrogen you see again the R group in
this case is hydrogen simplest one and
let's combine that with this another
amino acids and this is alanine and this
is abbreviated by G for example only
this is abbreviated as a like this now
the condensation reaction polymerization
reactions again as followed we get this
oxygen and two of the hydrogen here like
this to get the water molecule out and
the peptide simply linkage
and we have one hydrogen there like this
so this is the peptide bond is this one
here should probably okay this bond we
bond between this carbon and that
nitrogen is called the peptide bond
peptide bond or peptide linkage or
peptide bond okay so and this is
actually called dipeptides because we
have two amino acids now with the same
way we can add here in other amino acids
and other amino acids and other amino
acids we get a long-chain polymer right
and that becomes the protein that
becomes a protein now as you can simply
imagine the property of the protein will
be determined which amino acids we
condense to form the polymers and there
are in fact if you consider that we have
22 amino acids in nature and think about
that we can get up to 27 50,000 amino
acids add them to form the peptide link
so the sequence of those amino acids in
one protein will always be limitless you
can have different you can combine the
same amino acids but you can have
different proteins because the sequence
of those amino acids will be different
and that sequence is very very important
in determining what function the amine
the protein that is the obtain protein
will carry out in the living organisms
in the living organisms now this is
again I just just to show you this
peptide link it's the same things here
right you see that peptide link between
this carbon and that nitrogen over here
and now we have another peptide link
that carbon there this is a tripeptide
we have three amino acids remember we
can have 30 to 50 amino acids or more in
one chain protein that gives you the big
big molecular weight of proteins let's
continue now the protein structures are
also classified as primary structure of
proteins it is called the sequence of
amino acids in the polypeptide protein
chain what does that means that means
which amino acids that we will simply
bring together this is like glycine
alanine and other amino acids that
sequence it determines the primary
structure of the amino acids now the
secretary structure is the interactions
between the chain atoms in fact carbon
double bond oxygen this carbonyl and NH
atoms remember we will have a hydrogen
bond between that hydrogen and that
oxygen electron pairs on that oxygen
right lone pair electrons so that gives
this structure two proteins that
interaction is the hydrogen bond
interactions is a very very important
factor in determining the structure of
the particularly at secondary structure
of the proteins as we will see now
tertiary structures are intermolecular
forces between the sidechain atoms that
gives structure to proteins this is
simply the folding actually you know
when you have a long long chain of
protein molecule now it simply folds up
and the folding of the assembling of
that long chain folding is very very
important because the folding of the
amino acids
the shape of the amino acid determines
the protein the folding of the amino
acids in the protein determines the
shape of the protein and the shape of
the protein also determines the function
of the chemical functions of the protein
that will carry will carry out in the
living organisms we will see this now
the quaternary structures is another in
one protein we may have units subunits
and again the assembling of those
subunits arrangement of those multiple
units incorporated in non amino acid
proteins of proteins it gives you the
quaternary structures again let's see
what we mean by this this is again the
the structures of the protein this is
the primary structure right that means
the sequence of the amino acids which
amino acids are linked together by
peptide link and in this chain that's
the primary structure now the secondary
structure we may simply have the helix
type structure like this or we may have
a planar structure like this again
remember all of these structures we have
a very strong interactions between the
nitrogen and the oxygen groups again and
particularly the form in the helix
structure that allows the interactions
the hydrogen bonding between the strain
of the protein strain of the protein and
this is called the beta sheet it's sort
of a planar structures like this now
when you have those and fold them up
here like this
that becomes the tertiary structures now
if you have a bigger protein which have
subunits and have this kind of structure
again every subunit has different
structure this different assembling
structures and that gives you the
quaternary structures of the protein now
the primary structure formations of the
mi band between amino acid
repeats many times for polypeptide
protein again to get that million
molecular mass atomic mass unit for the
proteins it's a very very large long
chain here is the glycine and alanine
and we get the glycine alanine protein
and that we will add more and more of
that now the secondary structure as we
talked about that two common times it
says alpha helix as I showed you looks
like a corkscrew or spiral staircases
the carbon oxygen forms hydrogen bonds
with the nitrogen hydrogen from the
another amino acid in the chain right so
another strain of the amino acids now
better sheet two or more pleated regions
looking like a shape of the pleated
skirt or corrugated cardboard are held
together by the same hydrogen bonds as
an alpha helix one major difference is
how far apart from each other the amino
acids are in the amino acid sequence of
alpha helix atoms are much closer
together in alpha helix the hydrogen
bundles are taking place in much closer
distances in beta the beta sheet
structure again it is longer distance
hydrogen bonded now tertiary structures
side chains interact with each other and
the surrounding environment usually
aqueous environment the forces we called
intermolecular are mostly what drives
the tertiary structures we have the
intermolecular forces and the side
chains have polar nonpolar and charged
groups these give rise to ion ion ion
dipole dipole dipole and dispersion
force interactions and definitely
hydrogen bonds and hydrogen bonds is
definitely there too now the quaternary
structures some proteins are made up of
more than one polypeptide chain more
than one that means subunits some
proteins contain portions that are not
amino acids in the nature and the
combinations of subunits all these
subunits is quaternary structures when
they get together form a shape that's
the this fourth structure of the
proteins now this gives you another
classifications of proteins says one
method to classify proteins is based on
solubility global proteins are roughly
spherical and dissolve in aqueous
environment this is the globular that
means spherical type and fibrous
proteins long-chain are usually long
fibers that are insoluble in water and
are used as structural materials as
structural materials that means in the
living organisms like skins and muscles
and things like that as a matter of fact
now the second biopolymers is
carbohydrates now the name comes from
the empirical formula for sugars which
has this empirical formula for the
simplest sugars X is equal to Y which is
the glucose as we will see it now what
does this mean this means like we have X
carbon atoms and like we have this
carbon atom is hydrated with water
molecules hydration is simply means the
surround the atoms or the molecule with
water molecules but in reality the
carbohydrates they are not actually
carbohydrates they are simply compounds
of carbon hydrogen or oxygen that's it
right
but the ratio of the hydrogen and oxygen
always wanted to so that means we can
always write the formula as this certain
number of carbon atoms and certain
number of water molecules that's what we
call it high grade carbohydrates like
hydrated carbon hydrated carbon but in
reality it is not actually we have to
remember that now simple sugar which is
the monosaccharides are poly hydroxy
aldehyde or ketone
again this is what the plant synthesizes
in photosynthesis right in
photosynthesis they are often drawn as
chains but most frequently exists as
rings in solutions so for example
glucose this is the alpha glucose beta
glucose what is the difference the
difference actually is the positions of
this Oh H with respect to this group
over here these are in the same side and
over here this on this side that on that
side that's the alpha this is the beta
glucose actually six carbon and then we
have six oxygen and 12 hydrogen right
and it is an aldehyde it is an aldehyde
and also ketones as we say now here you
will see those this is the glucose six
carbon and it is an aldehyde you see
again we have a double bond and the
hydrogen at the end this is the aldehyde
and it also has a H group that means it
is actually a alcohol it is a poly
hydroxyl aldehyde poly hydroxyl aldehyde
now this is the fructose which is
present in fruits particularly and it is
also six carbon and the close formula is
exactly the same but this is a ketone
you see again the ketone there and again
we have the hydroxide group now remember
these are the monomers of
polysaccharides right polysaccharides
again carbohydrates or both yay now
disaccharide is simply obtained by
combining two of these glucose or
fructose units together and when you
combine these two units like glucose and
fructose and take out one water molecule
this is a gain of condensation right you
take H from one side hydrogen from one
side and one water molecule comes out
and we get actually a disaccharide that
means two monomers and this is sucrose
this is the table sugar actually we have
the glucose and fructose
combined together now if we combine two
glucose units together like this and it
becomes a lactose it is also sugar but
that is milk sugar right that is the
milk sugar again now then we can add
here more and more and make that chain
more and more longer and longer actually
and bigger and bigger molecule and then
we simply have the polymers now
polysaccharides as you can imagine means
containing more than one of those
glucose and fructose units as again
linked together by condensation
reactions and dehydration can create
long-chain polysaccharides dehydration
that's what the condensation reaction
means take out the water
dehydration means the three most common
are the these polysaccharides starch
glycogen and cellulose right and we know
the starch we know the cellulose cotton
and things like that right and glycogen
czar in the animals these energy storage
materials in the animals but even though
they look like you have very different
properties there are different functions
also but chemically they are all made up
from the same units that is the glucose
or fructose or the other six membered
sugar again right poly hydroxide
now Sarge consists of many different
size and various branch and chains of
glucose prepared by plans to store
energy so again the starch is used for
the plant to store the energy and it's
we also get our energy from the starch
to from what we eat potatoes we eat rice
we eat wheat and all of those contain a
lot of starch and our body simply
hydrolyzes that starch because the
enzymes that we have in our body
hydrolyzes that starts converts that
polysaccharide into the glucose and
fructose right
all units and those smaller units are
simply carried out and combusted in our
body to create to to release the energy
that we need for the survival right we
need for the survival so glycogen is
often called animal starch so it is
similar to that again but animals have
that glycogen or synthesizer collection
it is far temporary energy storage in
the animals it is called actually the
energy bank of the animals
fast for long-term energy storage again
now cellulose is a structural
polysaccharide in plants making up cell
walls
it is unbranched and particularly in
plants it is making up cell walls and so
on and it's unbranched now cellulose and
starch are both made from glucose
monosaccharide the same glucose but in
one case we have alpha glucose in the
other case we have beta glucose right
that difference makes the starch and
cellulose so different very very
different actually now if we eat
cellulose that will come out without
digestion x' actually without any change
you can just we can't do because we
don't have enzymes to convert the
cellulose into simple sugars those
monomers but we have our enzymes convert
the starch which is the same things to
the sugar the difference is one is the
alpha glucose the other one is beta
glucose you see again the enzyme is so
specific even that small difference make
the enzyme non active it's not simply
active at all in converting the human
enzymes actually convert into cellulose
to the sugar but the animals enzymes
because they eat grass and that contains
cellulose a lot of green things and can
just that because their enzymes break
the cellulose into monosaccharides and
they can use up those in their bodies
for the energy they needed okay these
are the structures you see again
polysaccharides here and I guess you can
have single units like this or double
like that and it is a polymer long-chain
polymer you know very very big molecules
now the others is the lipids the game
now lipids are not polymers actually are
not polymers lipids are broad class of
nonpolar bio organic molecules they are
grouped because they are insoluble in
water now they are used biologically to
store energy like fats and oils and for
biological structures phospholipids in
cell membranes now let's look at what is
a fats and oil
now when we combine glycerol this is an
alcohol plus three fatty acids and then
we get the fat now what is a glycerol
glycerol is is the structure actually
three carbons and I have an IH o H and O
H here and then two hydrogen's one
hydrogen and two hydrogen there now when
we combine it with fatty acids what is
the fatty acids fatty acids is actually
carboxylic acids long chain number of
carbon is between 16 and 19 right so we
simply have let's say CH 3 and then
let's call here CH 2 and make that one
let's make that 16 plus C oh oh and co h
this is the fatty acids again how many
carbons this says 16 17 18 carbons may
be up to 8 19 carbons now if you get
three of those and we get the
esterification x' actually we get the
esters and this simply Oh H takes out
one of that hydrogen's and then we end
up with this
all right this is the fat and plus we
have two three water molecules right
coming out there this is what we call a
fat now depending on the fatty acids
actually carboxylic acid these are long
carboxylic acid if it contains a double
bond then we have the unsaturated fat
and if it's all saturated then we have a
saturated fat but this is what the fat
is all about a glycerol and those fatty
acids that's all it is
let's look at here is what says fats and
oils are made from long-chain carboxylic
acids and glycerol actually when we say
oil that means it contains unsaturated
carbonyl unsaturated carbons if it all
saturated we call it fat like this are
made from long-chain carboxylic acid and
glycerol this is the long-chain
carboxylic acid and this is the glycerol
right
glycerol now fats have only saturated
carboxylic acids and they are solids
these are often called the bad fats in
your diet you know you don't want the
saturated one but we want these
unsaturated ones oils have at least one
unsaturated carboxylic acids they are
liquids the more unsaturated the better
for poly for you that means
polyunsaturated versus monounsaturated
fats we also have that now essentially
fatty acids with double bonds must be
included in our diet our bodies cannot
produce them they are often called
omega-3 and omega-6 fatty acids okay
here is the things now remember the we
say the omega-3 which the fish oil
contains a lot of omega-3 and very very
useful for health in fact right good
food the
omega-3 are the oils which have
unsaturated hydrocarbons from this end
in the third hydrocarbon that's the
Omega third carbon this is the first
carbon second third if you have a double
bond between third and fourth carbon
here in this chain and here and here
that's called the omega-3 oil right
omega-3 oil now if I have the double
bond on six carbon from this end it is
called omega-6 and these omega-3 on over
six are the oils that we meet and they
have to be taken outside they have to be
ingested that means we have to eat food
containing these omega-3 and omega-6 and
now our phospholipids are similar type
structure let's see how they are
arranged again you see how their
structures is similar to the facts we
have the glycerol with ester linkage to
two fatty acids instead of three okay
now for the lipids actually like here in
this formula we have three acids fatty
acids here but in the lipids we have 250
edges but here we have the phosphate
group here to fatty edges and one
phosphate group and that makes the lipid
actually how it differs the third side
has a phosphate ester linkage connected
to the charge or polar group such as
choline and that end actually which
contains a phosphate is a charge and
polar type side of the lipid molecule
the clustered together in water polar
regions they cluster together in water
such as polar regions pointing toward
the water and nonpolar fatty acids
regions pointing toward each other
forming a lipid by layer and the start
of
cell membrane the cell membrane is made
of like this again in this case we have
the water polar side and ionic side in
the water side and this is the ionic
side here and the nonpolar side and
organic part hydrocarbon parts is inside
so we have sort of a layer and which is
the structure of the membrane of the
cells is similar to that and we have
water and water here inside and outside
of the cell and that is the lipid very
very important structure part of the
cell living cells yes here is the
example again this is the fatty acids
fat actually I should say there are
fatty acids and that is the same as this
right over here just the open formula
and how many carbons I don't know but it
right down the carbons like this and
there is no unsaturated here so that
means this is going to be a fat from
fatty acids palmitic acid this is a
polymeric acid now when we have a lipid
and we have two acids just like here two
of those the third one is the phosphate
bond it over here like this and this is
the polar part there's some something
wrong here this is going to be CH 3
times 3 not ch2 but that is a positive
side there is a negative side here this
is a polar part that part is the one
which is in the water side and this part
is in inside of that lipid structure
that we have seen yes this one over here
this is the polar part and this is the
nonpolar part of the lipid and that's
called the phospholipids this is the fat
and this is the lipid and if I have a
double bond here then it becomes oil
right becomes oil
nucleic acids are another type of
biopolymers very very important class of
biopolymers that are chemically carriers
of genetic information this is very very
important as a matter of fact they carry
out the genetic information and there
are two types one is deoxy carbo
ribonucleic acid which is abbreviation
for this is DNA and this is ribonucleic
acid the abbreviations is RNA very close
structures I will show you how they
differ actually okay let's look at the
RNA and DNA nucleic acid types in a DNA
we have huge molecules six to 16 million
atomic mass unit really long chain long
chains and then here we have smaller
molecules RNA are smaller but when we
say smaller the atomic mass unit is from
20,000 to 40,000 years can you imagine
and now one mole of this substance will
be how many grams can you tell me one
mole of RNA if the atomic mass is 40,000
how many what is the mass one mole 40
kilograms right one mole is 40 kilograms
now if you come over here I guess Oh
sixteen million one mole will be 16
tonnes or something like that
16 tonnes can you imagine how big the
molecule one mole of water molecule one
more one more water is 18 grams right
just 18 grams one mole hydrogen is 2
grams so huge molecules as a matter of
fact primarily in nucleus of the cell
these are DNA DNA are found in nucleus
of the cell remember in a cell there is
a nucleus in the center so the DNA is
found in the center now mostly outside
of the nucleus in cytoplasm actually the
outside of the nucleus of the cell is
called cytoplasm now
Storrs genetic information so the
genetic information is stored in a DNA
structure and the this information is
carried from the nucleus of the cell
into the cytoplasm by the RNA actually
and the synthesis of the proteins
particular proteins are become possible
in the cytoplasm in in the cells
specifies which proteins the cell can
synthesize information is used in the
protein synthesis outside of nucleus so
this information actually carried out
from the nucleus of the cell to the site
applause by RNA let's see what else we
have this is the structure of the
nucleic acids in a nucleic acids we have
nucleotides and these nucleotides are
just like monomers like sugar in the
carbohydrates polysaccharides and so on
now what is this monomer or nucleotide
let's look at that we have a phosphate
group over here and we have a ribose
sugar again here and then five carbon
sugar and then we have what we call here
a base unit any Nick nuclear base equal
basis there are five different of those
this one is a base unit I guess this is
the other nine like this so now when we
combine these this is monomer put them
together from here from there and you
see again that is the polymer and this
part here the phosphate and here we have
the sugar part ribose here we have the
base and this is called the nuclear
bases actually and there are six
different bases as you will show you and
this is the polymer so I see we simply
have the nucleic acids polymer here now
which one what what is the difference
again is structure-wise between the
deoxyribonucleic acid DNA and RNA this
one is actually DNA
this unit monomer DNA in RNA we have
hydroxide here too
so when we simply change the hydroxide
to hydrogen it is called
deoxyribonucleic acid which is the
abbreviation DNA comes from now if I
have an hydroxide here two hydroxide
that becomes a right board nucleic acid
which is the RNA that's the only
difference between the ribose DNA and
RNA very clearly here in this part right
there and this is the polymer now the
double helix that formed by the DNA by
hydrogen bonding particularly hydrogen
bonding between those bases nuclear
bases nucleotides combine to form
familiar double helix form of the
nucleic acids this structure over here
now hydrogen bonding dipole-dipole
interactions and dispersion forces hold
the double helix together but mainly
hydrogen bonding here mainly hydrogen
bonded these are adenine and thymine and
so on like guanine guanine and adenine
thymine hydrogen bonding between the
nucleobases
and the nuclear bases as this part here
you see that part and that part there
are five different nuclear bases I guess
five different nuclear bases yes
now complementary bases pairs form ideal
hydrogen partners hydrogen bonding
partners for example alanine and thymine
Ryan makes a hydrogen bonding and this
is cytosine and guanine makes it ideal
hydrogen bonding and these hydrogen bond
ends makes this helix structure possible
helix structure