Biochem Lecture 3 Flashcards
(48 cards)
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
How are fatty acid chains named?
Carboxylic Carbon is number 1. Then count number of carbons in the chain. This number is followed by a colon and the number of double bonds and their position. 18:3^9,12,15 means an 18 carbon chain with double bonds at carbons 9,12,15. It can also be written as 18:3(9,12,15). The methyl group end is the omega end.
What is the omega numbering system for fatty acids?
They are classified by the closest double bond to the omega end. Such as omega 9. These are families of acids. This is where omega 3 fatty acids get their name.
What are branched chain fatty acids?
They have methyl groups attached along the fatty acid chain.
What are trans fatty acids?
Artificially made fatty acids that have trans double bonds instead of cis orientations which are the naturally occurring version of unsaturated fats. Trans configuration makes the chains straight instead of kinked.
What are triacylglycerols?
TAGs. The storage form of fatty acids. Includes three chains attached to a glycerol backbone. They are hydrophobic and non polar.
