Lecture 11: Carbohydrates I Flashcards
Aldose-ketose pairs are examples of which type of isomers?
Constitutional isomers
Name two different aldose-ketose pairs.
Glucose & Fructose
Glyceraldehyde & Dihydroxyacetone
What are constitutional isomers?
Molecules that differ in the order of attachment of atoms
Give an example of enantiomers.
D-glyceraldehyde & L-glyceraldehyde
Give 2 examples of diastereoisomers
D-glucose & D-mannose (epimers)
alpha-D-glucose & beta-D-glucose (anomers)
What are stereoisomers?
Molecules that have the same order, but the spatial arrangement is different.
Enantiomers & Diastereoisomers
What are enantiomers?
Nonsuperimposable mirror image molecules
What are diastereoisomers?
Isomers that are not mirror images
What is the Fehling’s reagent?
It is used to test if reducing sugar is in the urine…b/c you have more than normal amount in blood stream
What is Pyran?
A 6 atom ring with 5 C’s and an Oxygen
What is Furan?
A 5 member ring with 4 C’s and an Oxygen
What is a glycosidic bond?
When an anomeric C participates in bonding with a C of another sugar
What is the Maltose bond?
Alpha-1,4 bond between two glucose molecules
What is maltase?
The enzyme that breaks down maltose
What is the sucrose bond?
Alpha-1, Beta-2 bond between glucose & fructose
It’s a non-reducing sugar
What is the lactose bond?
Beta-1,4 galactose & glucose
What makes a sugar a reducing sugar?
It has a free anomeric C
What is lactase?
The enzyme that breaks down lactose
What is sucrase?
The enzyme that breaks down sucrose
What C position causes the difference between glucose/mannose?
The second C position is flipped (from anomeric C)
What C position causes the difference between glucose/galactose?
The fourth C position is flipped (from anomeric C)
T/F: Dihydroxyacetone and Glyceraldehyde are isomers.
True
T/F: Glucose relates to Fructose as an aldose-ketose pair.
True
What is an epimer?
An isomer that differs at one of several asymmetric C’s
What is an anomer?
Molecules that differ at new asymmetric C upon ring closer
What is Glycation?
Covalent bonding of protein or lipid with broken down sugar (3DG or MG), such as fructose or glucose, without controlling action of enzyme…
