Biochemistry Lecture Exam 3 Flashcards
Carbohydrate
aldehydes or ketones with at least two hydroxyl groups, or substances that yield such compounds on hydrolysis
Monosaccharides
simple sugars, consist of a single polyhydroxy aldehyde or ketone unit
Oligosaccharides
short chains of monosaccharides units joined by glycosidic bonds
Disaccharides
oligosaccharides with two monosaccharide units
Polysaccharides
sugar polymers with 1+ monosaccharides units
Epimers
two sugars that differ only around one carbon atom
Pyranose
six membered ring compounds
Furanose
five membered ring compounds
What is an aldose?
carbonyl group is at an end of the carbon chain (in an ALDEHYDE group)
What is a ketose?
carbonyl group is at any other position but the end (in a KETONE group)
Which isomer (D or L) are most sugars in nature?
D
For glucose, what carbon is the carbonyl carbon?
Carbon 1
For glucose, what carbon is the anomeric carbon?
Carbon 1
What cyclical form does glucose typically take?
Pyranose form is most common
What is an aldonic acid?
form following oxidation of the carbonyl carbon of aldoses
What is an uronic acid?
form following oxidation at carbon 6
What position of the sugar is the reducing end? How can that be used to detect sugar in a solution?
-Reducing End: the end of a disaccharide or polysaccharide chain with a free anomeric carbon
-Produces color change when combined with different sugars (we did this in lab so I think this is right)
What is a homopolysaccharide?
contain only one single monomeric sugar species; serve as storage forms and structural elements
What is a heteropolysaccharide?
contain 2+ kinds of monomers; provide extracellular support
Name two biologically important homopolysaccharides?
starch and glycogen
What are some roles of polysaccharides?
Mainly have structural and energy storage roles
What is the structure of glycogen? What types of bonds occur and what types of sugar is involved?
-Heavily hydrated with many exposed hydroxyl groups that are available to hydrogen bond
-Most stable 3D structure is a helical structure with six residues/turns; more extensively branched and more compact than starch
-made of glucose sugar
What are glycosaminoglycans and what types of modifications are made to the sugars found in GAGs?
-Glycosaminoglycans: heteropolysaccharides found in the ECM; linear polymers composed of repeating disaccharide units; unique to animals and bacteria
-Different groups on the GAG is the modifications (amine group, sulfate added, carboxyl added)
Glycoconjugate
biologically active molecule consisting of an informational carbohydrate joined to a protein or lipid