Carbohydrates Flashcards
What is an aldose?
An aldose is a monosaccharide that contains an aldehyde group.
What is a ketose?
A ketose is a sugar that contains a ketone group.
Picture of a Haworth projection.
Picture of a Fischer projection.
What are the simplest monosaccharide?
The simplest monosaccharides are glyceraldehyde and dihydroxyacetone
Only glyceraldehyde is chiral
Picture of glyceraldehyde.
Picture of dihydroxyacetone.
What is a furanose?
Furanose’s are sugars that have a five membered ring consisting of four carbons and one oxygen.
Derived from the structure of furan.
What is a pyranose?
Pyranoses are carbohydrates that have a six membered ring composed of one oxygen and five carbons.
They are derived from a pyran.
What is an anomeric carbon?
An anomeric carbon, or the carbonyl, is one that is bonded to two different oxygen atoms.
NOTE: Picture is of a-D-glucopyranose. It is of one of two possible forms of D-glucose. The anomeric carbon becomes chiral when the molecule cyclizes.
Picture of b-D-glucopyranose.
NOTE: b-D-glucopyranose differs from a-D-glucopyranose at the anomeric carbon.
What is a hemiacetal?
Hemiacetals are compounds that have an -OH and an -OR group on the same carbon.
Cyclic monosaccharides are hemiacetals and hemiaketals.
What is a hemiketal?
Hemiketals are compounds that have an -OH and an -OR group on the same carbon.
Cyclic monosaccharides are hemiacetals and hemiketals.
What is an acetal and ketal?
An acetal and ketal is a functional group with the following connectivity R2C(OR’)2, where both R’ groups are organic fragments.
The central carbon atom has four bonds to it, and is therefore saturated and has tetrahedral geometry.
Acetals and ketals are found in glycosidic bonds.
Picture showing glycosidic linkage.
What is sucrose?
Sucrose is a simple disaccharide made up of glucose and fructose.
The linkage is between anomeric carbons.
What are some other important disaccharides?
Maltose - Made up of two glucose units.
Lactose - Made up of galactose and glucose units
What are some important polysaccharides?
These are used for storage and structural purposes
Starch - Made up of amylose and amylopectin.
Amylose is made up of alpha 1-4 glycosidic bonds
Amylopectin is a branched form of starch and made up of alpha 1-6 glycosidic bonds
Cellulose and chitin are structural carbohydrates
Picture of amylose and amylopectin.
True or false: Catabolic and anabolic pathways must be regulated.
True
These pathways must be regulated, especially when they occur simultaneously.
What high-energy molecules couple catabolism and anabolism?
ATP and NADPH couple catabolism and anabolism.
