PRELIM 01 - Carbohydrates and Related Compounds Flashcards
Are hydrates of carbon; can be in the form of polyhydroxyaldehyde or polyhydroxyketone
Carbohydrates
General formula of carbohydrates
Cn(H2O)n
Cannot be hydrolyzed into simple sugars (Types of carbohydrates)
Monosaccharides
Has 2-10 sugar units (Types of carbohydrates)
Oligosaccharides
Has >10 sugar units (Types of carbohydrates)
Polysaccharides
2 types of monosaccharides according to functional group (AK)
Aldose, Ketose
Includes glucose and galactose (Types of monosaccharides; functional group)
Aldose
Includes fructose and erythrose (Types of monosaccharides; functional group)
Ketose
Simplest monosaccharide; does not occur free in nature (Types of monosaccharides; number of carbons)
Diose (Hydroxyacetaldehyde)
Includes glyceraldehyde and dihydroxyacetone (Types of monosaccharides; number of carbons)
Triose
Occurs commonly in nature, usually as products of hydrolysis of hemicelluloses, gums, and mucilage (Types of monosaccharides; number of carbons)
Pentose
A pentose that is known as “wood sugar”; used as a diagnostic aid for intestinal malabsorption; is absorbed but not metabolized
Xylose
The most important monosaccharide found in plants; includes glucose and fructose (Types of monosaccharides; number of carbons)
Hexose
The sweetest monosaccharide (Examples of hexose)
D-fructose (Levulose)
Also known as dextrose, grape sugar, and physiologic sugar (Examples of hexose)
D-glucose
Is an aldohexose that generally forms a 6-membered pyranose (Examples of hexose)
Glucose
Is a ketohexose that is a food for diabetics (Examples of hexose)
Fructose
2 cyclic forms of fructose (FF)
Fructofuranose, Fructopyranose
A fructose that is present in oligosaccharides and polysaccharides (Cyclic forms of fructose)
Fructofuranose
A fructose that has the structure of crystalline sugar (Cyclic forms of fructose)
Fructopyranose
A nonreducing sugar; upon hydrolysis, it yields invert sugar; also known as α-D-glucopyranosyl-3-D-fructofuranoside (Examples of disaccharides)
Sucrose
Upon hydrolysis, sucrose yields __________, which consists of equimolecular quantities of glucose and fructose
Invert sugar
Produced in large quantities by the hydrolysis of starch; an example of reducing sugar (Examples of dissacharides)
Maltose
Upon hydrolysis, maltose yields ____________ molecules of glucose through diastatic fermentation
2
Widely distributed in fungi; is an example of non-reducing sugar (Examples of dissacharides)
Trehalose
Also known as “milk sugar”; is an example of reducing sugar (Examples of disaccharides)
Lactose
General test for carbohydrates (Tests for carbohydrates)
Molisch’s test
Test for pentoses (Tests for carbohydrates)
Bial’s test
Test for ketoses (Tests for carbohydrates)
Seliwanoff’s test
Test for reducing monosaccharides vs. reducing disaccharides (Tests for carbohydrates)
Barfoed’s test
Test for starch (Tests for carbohydrates)
Iodine test
2 tests for reducing sugars (Tests for carbohydrates) (FB)
Fehling’s test, Benedict’s test
Test for galactose (Tests for carbohydrates)
Mucic acid test
Molisch’s test (Positive result)
Purple ring
Bial’s test (Positive result)
Bluish color
Seliwanoff’s test (Positive result)
Red product
Barfoed’s test (Positive result)
Dark red ppt
Iodine test (Positive result)
Blue-black complex
Fehling’s test and Benedict’s test (Positive result)
Red ppt
Mucic acid test (Positive result)
Formation of colorless crystals
In Molisch’s test, monosaccharides react at a faster rate, about __________ to __________ seconds
1-3
In Molisch’s test disaccharides and polysaccharides react at a slower rate, about more than __________ seconds
5
Reagent for Fehling’s test composed of copper sulfate sodium
Fehling A
Reagent for Fehling’s test composed of Rochelle salt (Sodium potassium tartrate); most commonly used
Fehling B
