Disaccharides, Lactose, Maltose, Sucrose Video Lecture - NEET

hello friends this video on biomolecules
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this we'll end our discussion on
monosaccharides and monosaccharides what
do you want all did we learn we saw that
monosaccharides are the simplest sugars
which cannot before you're hydrolyzed so
we have dispersed mainly to
monosaccharides that is glucose and
fructose they're open structures they're
cyclic structures how they can be
prepared so now let us talk about the
next group of carbohydrates that is
disaccharides that is those
carbohydrates which on hydrolysis gives
two units of monosaccharides so some
common examples of disaccharides would
be sucrose so close which is the cane
sugar lactose the sugar which is present
in milk and maltose the sugar which is
present in vegetables and germinating
seeds so these these three are very
common examples of disaccharide switch
which consists of two monosaccharides
units so here you can look at the
structure of sucrose so this is the
structure of sucrose so you can see this
is one glucose unit and one from toes
unit and they are joined together by a
glycosidic linkage so that is the
structure of sucrose so when we talk
about disaccharides so disaccharides on
hydrolysis what will it give it will
give two monosaccharides two units of
monosaccharides so it is an important
point to note is the those two units of
monosaccharides can be same or different
for example in case of sucrose the two
units are glucose and fructose so they
are different but when you talk about
monteux's you have both the units same
now what happens the other way around
how the monosaccharides are joined
together that is by the process of
dehydration synthesis so that it has
been shown here so if you has a blue if
you have a glucose and fructose what
happens this Oh H and this Oh H will
come together so it will lose one H 2 O
so this is got dehydration synthesis
dehydration synthesis dehydration
because it is steak pulling out one
water molecule synthesis because it is
synthesizing something it is forming a
new of a new unit so that is how a
glycosidic bond is formed that is si o
si this is a glycosidic linkage so this
linkage between two smaller saccharide
units which occur due to a loss of water
molecule to form a disaccharide is known
as a glycosidic linkage so please
remember this concept of glycosidic bond
formation now let us look at some of the
examples of disaccharides sucrose which
is made up of glucose and fructose
sucrose is made up of glucose and
fructose monteux's which is present in
the germinating seeds like body or it is
also present in vegetables like potato
and all of the stuffs lactose which is
present in milk so lactose the word
lactate lactic acid blackboard is
related to make lactose is present in
milk so these are some of the very
common examples of disaccharides so here
if you see my toes is made up of glucose
and glucose that is 2 units of glucose
when you look at lactose it is made up
of one unit of glucose and when you
garlic dose so these are some of the
very common examples of disaccharides
now let us talk about some of the
disaccharide so first we'll talk about
sucrose so sucrose is an organic
compound which is commonly known as
table sugar
this is c12 h22 o11 this is sucrose so
how is sucrose formed again see
everywhere it is the same concept the
same things does that I am trying to
provide a separate slide for each of
them so that it for a better
understanding of yours so when you talk
about sucrose it is one glucose so this
is one glucose unit and one fluctus unit
they will join together they lose one
water molecule so by this process it
will form so close by formation of this
glycosidic bond so this is how some
crews will be formed from glucose and
fructose
similarly on sucrose hydrolysis it will
give an equal molar move mixture of
glucose and fructose sucrose when
hydrolyzed that is when water is added
it will give glucose and fructose so
this is how the structure will look like
this o H bonds will come and the
glycosidic bond will be broken down so
closes dextrorotatory but after
hydrolysis gives you a poorly ativy
mixture so when you look at the
chemistry of each of these compounds it
is found that sucrose is dextrorotatory
whereas both glucose and fructose both
of them and therefore auditory so it is
a it is something very surprising that
sucrose on hydrolysis gives two units
which are both laboratory free so that
is why it is often known as invert sugar
that is it gets inverted the nature of
it it's inverted now if you want to get
better understand
dextrorotatory laboratory please refer
chemistry videos because I am NOT good
getting into those details because I am
assuming that you know all those stuff
from your chemistry knowledge so let us
talk about monteux's maltose is composed
of two glucose units in which c1 of one
glucose is linked to c4 of neither
glucose so if you see this carbon-carbon
bond is linked with carbon 4 by this
glycosidic linkage or glycosidic bond
whatever you call it so two units of
glucose so this is an example of a
disaccharide which is made up of two
similar monosaccharides so on hydrolysis
of maltose you will get two similar
units the third one that is lactose it
is commonly known as milk sugar so
generally you would have observed that
anything related to milk is named after
lat for example for kids you have lacked
ocean well that is a substitute for milk
you want lactation period for women when
they are feeding their babies so you
call lactic acid it is something related
to milk in lactose it is the sugar which
is present in milk it is composed of
galactose and glucose so here you can
see the linkage between c1 and c4 carbon
atoms
so this is the glycosidic bond it is
made up of these two so this bond is
formed by loss of one water molecule
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