Carbohydrates Flashcards
What is the simplest ketose?
Dihydroxyacetone
What is the simplest aldose?
Glyceraldehyde
What are the building blocks of carbohydrates?
Monosaccharides
How many functional groups are found in Carbohydrates? Enumerate.
2 functional groups, either alcohol (polyhydroxy) and aldehyde or alcohol and ketone.
What type of bond joins monosaccharides together?
Glycosidic bond
Differentiate the structure of an aldehyde and a ketone.
Aldehyde is RCHO. Ketone is RCOR.
How are open chain monosaccharides best described?
Fischer Projection
The term ‘sugar’ is used for what specifically?
Monosaccharides and Disaccharides
Describe the structure of D-glucose with your hand.
lill
What are the symbols for dextrorotatory and levorotatory?
Dextrorotatory - d, (+)
Levorotatory - l, (-)
What are epimers?
Epimers are structures that differ only in configuration at 1 C atom.
D-glucose and D-mannose are epimers at what Carbon atom?
C2
D-glucose and D-galactose are epimers at what Carbon atom?
C4
What monosaccharides are functional isomers?
D-glucose and D-fructose are aldose-ketose pair.
What type of glucose occurs in nature? D-(+)-glucose or D-(-)-glucose?
D-(-)-glucose
In what form, do monosaccharides exist as open chains?
Crystalline form
Glucose in water, will react with itself, resulting in what formation?
Hemiacetal formation (the reaction of an alcohol with an aldehyde). The OH at C5 will react with C1.
How are cyclic structures of monosaccharides represented?
Haworth Projection
What is the cyclic structure name for aldohexoses?
Pyranose ring (6C)
A furanose ring is used for what type of monosaccharides?
Aldopentoses and Ketohexoses
Give an example of a aldopentose.
Ribose
Give an example of a ketohexose.
Fructose
What type of isomer is seen in Fischer Projection?
Epimers
What type of isomer is seen in Haworth Projection?
Anomers
What are anomers?
Anomers are isomers that differ only in configuration at C1.
Differentiate α-anomer and β-anomer.
α-anomer = OH - down β-anomer = OH - up
The mixture of an aldehyde and a ketone forms what type of sugars? Reducing or Non-reducing?
Reducing sugars
The only non-reducing sugar.
Sucrose
Monosaccharides of sucrose
Glucose and Fructose
Monosaccharides of lactose
Glucose and Galactose
Monosaccharides of maltose. Compare with cellubiose.
Maltose = 2 Glucose linked by α 1-4 ; Cellubiose = 2 Glucose linked by β 1-4
Monosaccharides of cellubiose. Compare with maltose.
Cellubiose = 2 Glucose linked by β 1-4 ; Maltose = 2 Glucose linked by α 1-4
Differentiate oligosaccharide and polysaccharide.
Oligosaccharide < 20 monosaccharides ; Polysaccharides > 20.
Maltotriose is composed of what?
3 Glucose
Give an example of an oligosaccharide.
Dextrin
What is a homopolysaccharide?
A polysaccharide composed only of 1 type of monosaccharide.
What is a glucan?
Glucans are polymers of glucose.
What are the subunits of starch?
Amylose and Amylopectin
Differentiate amylose and amylopectin. Describe their structure and solubility.
Amylose is linear, α 1-4, water insoluble
Amylopectin is α 1-4, α 1-6 (branching every 25-30 glucose units), water soluble
What is the storage form of carbohydrates in animals and humans?
Glycogen
Starch, Glycogen, Cellulose and Dextran are homopolysaccharides composed of what?
Glucose
Describe the glycosidic bonds of glycogen.
Branched : α 1-4, α 1-6 every 8-12 glucose units
Describe glycosidic bonds of cellulose.
Linear : β 1-4
What anomer of amylase exist in humans?
α-amylase
Chitin is composed of repeating units of what?
N-acetylglucosamine. Chitin serves as the exoskeleton of insects and crustaceans.
Describe glycosidic bonds of dextran.
Branched
Linear at α 1-6
Branched at α 1-3
What are heteropolysaccharides?
Polysaccharides composing of more than one type of monosaccharide.
Building blocks of Heteropolysaccharides
Disaccharides
Hyaluronic acid, Chodroitin SO4, Dermatan SO4, Keratan SO4, Agarose, Heparan and the Glycan in Peptidoglycan are examples of what?
Heteropolysaccharides
Where is hyaluronic acid found?
Vitreous humor, Synovial fluids (as lubricant)
Where is chondroitin SO4 found?
“Chondros” means cartilage. They are found in cartilages, synovial fluids and ligaments.
Where is dermatan SO4 found?
Skin
What is the best source of agarose?
Seaweeds
What is the use of heparan SO4?
Anticoagulant
Where is peptidoglycan found?
Cell wall of g (+) bacteria
The glycan in peptidoglycan is composed of what monosaccharides?
N-acetylglucosamine and N-acetylmuramic acid
