Chapter 7 Flashcards
(34 cards)
What are monosaccharides?
The simplest form of carbohydrates, consisting of single sugar molecules.
Smallest is glyceraldehyde
What is the difference between aldose and ketose?
Aldose contains an aldehyde group, while ketose contains a ketone group.
Both contain a C=O group, classified by which carbon contains the C=O group (1 or 2)
What are the classifications of monosaccharides based on the number of carbon atoms?
- Triose
- Tetrose
- Pentose
- Hexose
What are D and L enantiomers?
Isomers that differ in the configuration around the chiral carbon farthest from the carbonyl group.
L isomers contain the -OH on the left, and D isomers contain the -OH on the right
What is the difference between epimers and diastereomers?
Epimers differ in configuration at one specific carbon, while diastereomers differ at more than one chiral center.
What is cyclization of monosaccharides?
The process where linear forms of monosaccharides form intramolecular cyclic structures.
What are furanose and pyranose forms?
Furanose is a five-membered ring form, while pyranose is a six-membered ring form of monosaccharides.
What defines α and β stereoisomers?
They are defined by the orientation of the hydroxyl group at the anomeric carbon.
What is the anomeric carbon?
The carbon in a cyclic sugar that was the carbonyl carbon in the linear form. Can still flip back into the carbonyl carbon when the sugar transitions back into its linear form.
What is a reducing sugar?
A sugar that can donate electrons or reduce another molecule. A reducing sugar has to have a free anomeric carbon (contains a hydroxyl group).
What are disaccharides?
Carbohydrates formed by the linkage of two monosaccharides. The linkage is referred to as a glycosidic bond.
How can you recognize linkage notations in disaccharides?
By notations such as α1→4 or β1↔1β.
What distinguishes reducing from nonreducing disaccharides?
Reducing disaccharides contain a free anomeric hydroxyl group, which can be oxidized. Nonreducing disaccharides lack a free anomeric hydroxyl group because both anomeric carbons are involved in the glycosidic bond
What are homopolysaccharides?
Polysaccharides made up of only one type of monosaccharide.
Often serve as storage and form structural elements
What are heteropolysaccharides?
Polysaccharides composed of two or more different types of monosaccharides.
Provide structural support or information
What is starch and where is it found?
A storage polysaccharide found in plants.
Amylose and amylopectin cluster together in starch granules, and form double helices.
What is amylose made of?
Long, linear (unbranched) chains of glucose units connected by α1→4 linkages.
What is amylopectin made of?
Branched chains of glucose units with both α1→4 and α1→6 linkages every 24 to 30 units.
What is glycogen and where is it found?
A storage polysaccharide found in animals. Glycogen is a polymer of glucose, with chains formed by α1→4 linkages, and branched points formed by α1→6 linkages every 8 to 12 units.
What is cellulose made of?
Linear chains of glucose units connected by β1→4 linkages. Forms a very tough structure and is insoluble.
How does hydrogen bonding contribute to the structure of cellulose?
It provides strength and stability to the structure.
H-bonds form between adjacent monomers and chains of cellulose
What is chitin and where is it found?
A structural polysaccharide found in the exoskeletons of arthropods, spiders, crabs and insects, and cell walls in mushrooms
What are glycosaminoglycans?
Long unbranched polysaccharides composed of repeating disaccharide units.
One monomer is either N-acetyl-glucosamine or N-acetyl-galactosamine. The other monomer is uronic acid
What is the general structure of proteoglycans?
Core proteins with one or more sulfated glycosaminoglycan chains attached.
