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Carbohydrates (continued)
The simplest ketone is acetone. Aldehyde plus alcohol makes Hemiacetal and it
happens spontaneously and is reversible and does not require enzyme reaction.
Glucose is the main sugar in the blood. Galactose is a component of glucose. You
must memorize the structure of galactose. Lactose is the sugar found in milk. If there
is a problem in metabolism of lactose it is a very big problem. Galactose is important
in metabolism and in diseases. The end in -imia means concentration of the thing in
the blood. The reaction from galactose to glucose is not spontaneous and it requires
enzymes. Epimers means that there is only a change in the hydroxyl group from
right to left and it changes the whole type of sugar from galactose to glucose and
vice versa. This must be only to one hydroxyl group. Give me examples of epimer?
Glucose and galactose is an example of epimers. Epimerase is the enzyme that
changes the sugar to its epimer. This is where it got its name from. Mannose differs
from glucose only from one hydroxyl. So, mannose and glucose are epimers of each
other. Mannose and galactose are both epimers of glucose however they are not
epimers of each other. Fructose is a component of ketohexose. It is a ketoes. Carbon
number 2 carries the ketone group. Fructose and glucose can be converted easily to
each other in the body. All you have to do is change the functional group at carbon 1
and carbon 2. Know the structure for fructose, mannose, galactose, glucose, and
ribose. You should be able to recognize gluconate. When sugars are oxidized, the act
as reducing agents. Reducing sugars act as reducing and there has to be an aldehyde
group. Ketoes can also be reducing sugars in solution because it is in equilibrium.
Fructose is a reducing agent. Ketoes and aldos are in equilibrium and this is why
they were converted to reducing sugars. Sorbitol is not a sugar even though it has a
sweet taste. What is the product of fructose reduction? And think about the answer
of it. If mannose is without an aldehyde group it is then called manetol. Glycoside is
a compound that results from the condensation of glucose and alcohol. Oside means
compound of glusoce and alcohol. -Ose means sugar. Glycosidic bond and alpha
glycosidic bond. Once this bond is formed it is locked and the ring is locked and it
cannot open to be an open chain and it is no longer a reducing agent. Why? Because
the alpha is involved with a glycosidic reversible and it is not spontaneously broken
and this is why it is no longer reducing. Glycosidic bond is the bond between the
anomeric carbon and alcohol. Glycosidic bond can be either alpha or beta and this
bond is considered locked. What is the reduction product of fructose? It is also
called a ketohexose. How do I know what the reduction product is. Reduction of
glucose gives us sorbitol. Fructose is attached to only 3 atoms therefore it is achiral
and when it is reduced the OH group will come to the top or bottom and on either
way it forms alcohol. Therefore it gives us sorbitol and manitol. These are alcohols.
The carbonyl carbon is attached to 2 alcohols. Know how to tell if a bond is a
glycosidic bond. This bond happens between the anoremic carbon and a OR group.
The alcohols that reacts with can be an acid or a sugar, after all sugar is considered
an alcohol. This is then called a dissacharide. The glycosidic bond is considered to be
an alpha if it is on the bottom and beta if it is on the top. You can still have a
reducing sugar with a glycosidic bond because it can still form because it is 50%.
Acid with alcohol gives us ester. You should be able to recognize the ester group.
The phosphate with alcochol gives us phosphate ester and this is what happens.
glucose 6 phosphate. Know what the hell is this???? When fructose is reduced with
an enzyme it will not give you 2 things each 50%, it will give you one product
100%.`
Disaccharides
Maltose is the first example we will talk about. Disaccharides are connected by a
glycosidic bond and you need to know everything about maltose that is on the slide.
Lactose is reduced from galactose and glucose and it is a beta type of bond and it a
reducing sugar. Mammary milk contains lactose. The only difference in lactose and
maltose is in carbon #4. Anomeric carbon is the aldehyde group. Sucrose is highly
purified and it is in large use in the world. Sucrose is very highly concentrated. This
is why jam is made, anything that will think aboyt living between it will have all t eh
water sucked out of it and it will die. This is why bacteria does not live in the jam, it
will die.
Polysaccharides
These sugars are polymers and can be joined together by glycosidic bond. I can have
a chain as long as I want. Cellulose, in carbon number and they are joined by beta
shit the starch is joined by alpha and they look like a helical structure. Chairs are
made up of carbohydrates. Amylopectin is 80% and 20% is amylose. At the branch
exactly it is 1,6 then it is 1,4. It is highly branched. There is only one end where the
carbon number one is free the others are all attached. Amylopectin is in plants and
glycogen is in animals they both have the same basic structure the only difference ia
that the glycogen is much more branched. Cellulose is found in plants.
Heteropolysaccharides are gelatin is chemically glycosaminoglycans. For the time
being just know the 2 examples before in the slides when we spoke about the amine
sugars. Heparin and chonrotin sulfate are the 2 examples we need to know.