My Carbohydrates quizlet
Fructose is a six-carbon __________-containing sugar
KETOSE
Unlike starch and glycogen, cellulose is considered a *structural* molecule. Why?
It has *BETA-(1-4) LINKAGES* instead of alpha-(1-4)!
Why can't sucrose form glycosidic bonds with any other molecules?
It has no free anomeric carbons to do so!
The carbonyl carbon (carbon number one) becomes the new chiral center when cyclized. This chiral center that is apart of a cyclic molecule is called the ________________.
*ANOMERIC CARBON*
_________ is the primary structural component in plant cell walls, and is composed of B-(1-4)-linked glucose
*Cellulose*
D-Altrose and D-Glucose and examples of __________
*DIASTEREOMERS*
_____________ are the most common type of oligosaccharides.
*Disaccharides*
D-Glyceraldehyde and L-Glyceraldehyde are examples of ___________
*ENANTIOMERS*
_____________ are proteins that are covalently linked to carbohydrates through N- or O- linkages.
*GLYCOPROTEINS* (half carbohydrate half protein)
________ is a glucose storage molecule in plants, and is composed of a-(1-4)-linked glucose
*Starch*
Five-membered oxygen-containing rings are called...
*furanoses*
In aldohexoses (like glucose), cyclization occurs between C-1 and C-5 to form a cyclic ________.
*hemiacetal*
In ketohexoses (like fructose), cyclization occurs between C-2 and C-5 to form a cyclic ________.
*hemiketal* (carbon one has two groups instead of one group and an H)
D & L configurations reger to the configuration of the ...
*highest numbered asymmetric carbon* (largest number... farthest away from aldehyde or ketone)
Polysaccharides, molecules containing hundreds to thousands of sugar units, can either be ________ or __________.
*linear* or *branched*
Six-membered oxygen-containing rings are called...
*pyranoses*
What are the two polysaccharides that *occur together* in starch?
1. AMYLOSE (linear) 2. AMYLOPECTIN (branched) both are *homopolysaccharides* of glucose (strictly glucose)
What are the two main categories of stereoisomers?
1. Enantiomers (mirror images) 2. Diastereomers (not mirror images)
What are the four functions of carbohydrates?
1. Energy source 2. Cell wall component 3. Cell recognition molecules 4. Precursors for other biological molecules (amino acids, lipids, purines, and pyrimidines)
What are the two classes of diastereomers? Explain both
1. Epimers: differ at one of several asymmetric carbon atoms 2. Anomers: differ at a NEW asymmetric carbon atom formed on ring closure
1. What is the main storage polysaccharide in animals? 2. How does it differ from amylopectin?
1. GLYCOGEN 2. Similar to amylopectin, but it has many more *branch points* (more compact)
1. On pyranoses, the anomeric carbon is carbon number ____. 2. On furanoses, the anomeric carbons is carbon number ____.
1. ONE 2. TWO
1. After forming a glycosidic bond, the side with a free anomeric carbon is called the.... 2. The side within an anomeric carbon is called the...
1. REDUCING (hemiacetal) END! 2. NONREDUCING END!
1. An aldose contains a _________ functional group 2. A ketose contains a ________ functional group
1. aldehyde 2. ketone
For D-sugars (highest numbered chiral carbon has -OH on right): 1. An -OH pointing UP on the anomeric carbon makes the molecule... 2. An -OH pointing UP on the anomeric carbon makes the molecule...
1. beta (B) 2. alpha (a)
1. Starch and glycogen are __________ molecules. 2. Chitin and cellulose are ___________ molecules. 3. Cell surface polysaccharides are ____________ molecules.
1. storage 2. structural 3. recognition
In amylopectin, the branches occur approximately every _____________ residues of glucose.
12-30 (can be a1-4 or a1-6)
Glucose is a six-carbon ____________-containing sugar
ALDEHYDE ("aldohexose")
a-D-Glucose and b-D-Glucose are examples of...
ANOMERS (anomie's must be in ring form!)
Two sugar molecules can be joined via a glycosidic bond. Which two carbons do glycosidic bonds forms between?
An *anomeric carbon* and a *hydroxyl carbon*
Do sugars normally exist as open-chains or cyclic molecules?
Cyclic molecules!
*N-linked* glycoproteins involve which amino acid?
Asparagine
What type of reaction occurs when a glycosidic bond forms?
CONDENSATION! (H₂O is given off!)
On what side of a carbohydrate do you start the carbon numbering?
Carbon number 1 is on the side with either the ketone or aldehyde!
The common ratio of carbon, hydrogen, and oxygen in carbohydrates is...
Cn(H₂O)n
Natural sugars possess the ___-configuration
D-configuration!
Both D-mannose and D-galactose are *epimers* of ____________, but they are NOT epimers of each other.
D-glucose (epimers differ ONLY in the configuration around one carbon atom!)
D-Glucose and D-Mannose are examples of...
EPIMERS
Galactose only differs from glucose around carbon number 4, making these two molecules _________.
EPIMERS
Where is glycogen typically stored?
In the liver and muscle cells
What is the common monosaccharide that will form a furanose ring?
Fructose! (cyclization happens between C-2 and C-5!)
Lactose, a sugar found in milk, is composed of which two monosaccharides?
GALACTOSE and GLUCOSE
In the ring form, how to we determine if it is L or D?
Look at carbon 5 and see if the -CH2OH group is pointing up (D) or down (L)
*O-linked* glycoproteins involve which two amino acids?
Serine and threonine
In which area of the body are disaccharides digested?
Small intestine (sucrase breaks down sucrose; lactase breaks down lactose)
What do the Beta-(1-4) linkages allow cellulose to do?
Stretch out and *HYDROGEN BOND* with neighboring polysaccharide strands! Makes it very tough and rigid!
What is the LEAST number of carbons a monosaccharide can have?
THREE!
Lactose and sucrose are examples of ______________
disaccharides
Carbs are classified as mono-, di-, oligo-, and polysaccharides according to...
the number of *simple sugars* they contain
