Biochemistry : Identifying Monosaccharides
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Example Questions
Example Question #5 : Help With Organic Carbohydrates
Identify the aldose pictured, including its alpha or beta designation.
The structure pictured is mannose because the hydroxyl groups at carbons 2, 3, and 4 are situated cis, cis, and trans (respectively) to the 
The mannose pictured is in alpha form because the hydroxyl group at carbon 1 is trans to the 
Example Question #1 : Help With Organic Carbohydrates
The Fischer projection pictured is a form of glucose. The carbon labeled "x" is the chiral carbon farthest away from carbon 1 and the hydroxyl group connected to carbon "x" is on the right. This fact designates that the glucose as what configuration?
Alpha
Pyranose
Beta
L
D
D
The chiral carbon farthest away from carbon 1 is designated as "D" if its hydroxyl group is on the right side in the Fischer projection. In other words, this is D-glucose because the hyroxyl group on carbon "x" is oriented to the right.
Example Question #251 : Biochemistry
What is the name of the aldose pictured in this Fischer projection?
L-fructose
D-arabinose
L-xylose
D-ribose
L-lyxose
D-ribose
The structure is D-ribose because it is a five-carbon aldose with the hydroxyl groups on carbons 2, 3, and 4 all on the right in the Fischer projection.
Example Question #41 : Identifying Biochemical Molecules
Which of the following is not a monosaccharide?
All of these are monosaccharides
Lactose
Fructose
Glucose
Galactose
Lactose
While glucose, galactose, and fructose are all monosaccharides, lactose is a disaccharide comprised of two monosaccharides, glucose and galactose, joined by a 
Example Question #41 : Identifying Biochemical Molecules
L-Glucose is found as 2 different hexose stereoisomers in solution: 
Suppose both 
Both stereoisomers
Neither stereoisomer
Neither stereoisomer
In nature, L-sugars are indigestible by humans. In the case of L-glucose, even though our bodies can break down polymers of 
Example Question #253 : Biochemistry
Which of the following compounds is not a monosaccharide?
Galactose
Ribose
Glucose
Lactose
Fructose
Lactose
Out of all the sugars listed, lactose is the only one that is not a monosaccharide. Lactose is composed of a glucose and galactose bound together in a glycosidic linkage.
Example Question #42 : Identifying Biochemical Molecules
Which sugar is another name for "blood sugar?"
Lactose
Sucrose
Fructose
Glucose
Glucose
Glucose is also called "blood sugar" because it is the main sugar found in our blood. Sucrose is what we know as "table sugar" because it is commonly found in our kitchens and used in baking etc. Fructose is also known as "fruit sugar" because it occurs in naturally-occurring fruits, giving them their sweetness. Lactose is sometimes called "milk sugar" because it is found in milk.
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