Biochem EX1 - Carbohydrates Flashcards
What are carbohydrates? Aldoses? Ketoses?
Carbohydrates are Polyhydroxy aldehydes, polyhydroxy ketones or products that can be hydrolyzed to form these products.
Aldoses are monosaccharides having an aldehyde group.
Ketoses are monosaccharides having a ketone group.
What is the most important monosaccharide, and what polysaccharides are made up of this saccharide?
Glucose is the most important monosaccharide. Starch, cellulose, and glycogen are polymers of glucose.
Pyran and furan are organic compounds for which what sugar structures are named? How many atoms per ring?
Furanoses and pyranoses are name for furan and pyran. Furan has 5 atoms per ring and pyran has 6.
What is mutarotation, and where does it take place?
Mutarotation involves changes in configuration at the anomeric carbon by ring opening and closing.
What are two conformations of 6 membered rings?
Chain and boat conformations
How are sugar acids named?
Aldonic - acid terminal aldehyde group is oxidized to an acid
Uronic - acid terminal hydroxy group is oxidized to an acid
Name and describe two commonly found modifications of sugars.
Amino sugars are formed when one hydroxyl group is replaced by an amine group.
Deoxy sugars are formed when one hydroxyl group is replaced by a hydrogen.
What is a glycoside and an aglycone?
Glycosides are formed when the anomeric hydroxyl group of a sugar reacts with another hydroxy compound. The sugar providing the anomeric carbon is the one the compound is named for, the other is known as the aglycone.
Which of the three most important polysaccharides have alpha linked sugars? Beta linked? What is the importance of this?
Alpha - Starch
Beta - Cellulose
The importance is that beta linked sugars are not digestible by humans.
Name three important disaccharides and tell which have alpha or beta linked sugars.
Maltose, Lactose (beta), Sucrose (alpha)
Tell what glycosaminoglycans are, and name two important ones.
They are unbranched polysaccharides made up of repeating disaccharides where one is an amino sugar and the other is a uronic acid.
In the A, B, O blood group substances where is the difference in the structure of the oligosaccharides located? How many sugars are different?
There is a one sugar difference. The difference in their structure is the presence or absence of N-acetyl-galactosamine or galactose linked to the penultimate galactose by a C1 to C3 linkage.
