Biochem Lecture 3 Flashcards
What are the two types of carbohydrates?
They are either aldoses or ketoses, meaning they either have an aldehyde group or a keto group.
What is an aldehyde group?
H-C=O at the end of a chain.
What is a keto group?
C=O with the C connected to two other carbons.
What are sterioisomers?
Same chemical formula and sequence. Only difference is orientation of the atoms.
What are epimers?
Sterioisomers that differ at only one location.
What are enantiomers?
These are mirror images of each other. They can have identical characteristics such as having the same sweetness.
What is mutarotation?
When linear sugars spontaneously form into rings.
What are anomers?
Anomers are the two versions of a cyclical sugar in regard to the position of the anomeric -OH group being above or below the plane of the sugar. Both versions interconvert through the linear form.
What is Glycation?
Non-enzymatic single linear glucose reacts with amino groups of proteins to eventually form Advanced Glycation End Products or AGE’s. This is what is tested in the A1c test for diabetes. Takes place wherever glucose is present. Usually reduces physiological function.
What is glycosylation?
Enzymatic reaction of glycans (polysaccharides) happens in ER and Golgi as post processing. Produces functionally modified molecules such as glycolipids and glycoproteins.
Oxidation is…
Loss of electrons
and loss of Hydrogen or
gain of an oxygen atom or hydroxyl group.
Reduction is…
Gain of electrons and subsequently a gain of Hydrogen or a loss of Oxygen atom.
How do sugars become acids?
Through oxidation of the aldehyde carbon, sugars become negatively charged acids. The ending is changed from -ose to -onic acid or -onate. If the terminal hydroxyl group is oxidized, it becomes uronic acid or uronate. End up with a COO- on the end (carboxyl group)
How are sugar alcohols made?
If the aldehyde is reduced, all the carbons contain hydroxyl groups and the sugar is a polyol. If one of the hydroxyl groups is reduced, the C contains only H and it becomes a deoxysugar.
What is an amino sugar?
The sugar contains an amino group in place of a hydroxyl group.
What is an N-Acetylated amino sugar?
The amino group is acetylated, which adds a C=OCH3 on the amino group.
What are GAGs?
Glycosaminoglycans. Linear polymers of repeating disaccharides. Negatively charged.
What are glycosides?
Molecule where sugar is bound to another functional group via enzymatic reaction. Called a glycosidic bond which can be either O-linked or N-linked.
What are the three common classes of lipids?
Fatty acids,
Non-membrane lipids
membrane lipids