Lecture 7- Carbohydrate chemistry (8/19) Flashcards

(41 cards)

1
Q

To be chiral an alcove must have ? sugars and a ketone must have? sugars

A

aldose 3

ketose 4

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2
Q

Glucose can cyclize to form a

Fructose can cyclize to form a

A

hemiacetal

hemiketal

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3
Q

What are anomers?

A

isomers of monosaccharides that differ only in their configuration about that asymmetric carbon

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4
Q

What are receding sugars?

A

sugars with a free anomeric carbon. They will reduce oxidizing agents such as peroxide, ferricyanide, and some metals.

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5
Q

Redox reaction convert sugars to ?

A

Sugar acids

Aldehydes and ketones

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6
Q

Is glucose a reducing sugar?

A

yes,

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7
Q

Formed by mild reduction of sugars

A

sugar alcohols

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8
Q

What are sialic acids ?

A

N-acetyl and N-glycolyl derivatives of neuraminic acid

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9
Q

Acetals can be formed from hemiacetals as a result of ?

A

Dehydration synthesis

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10
Q

Pyranose and furganose form of monosaccharides reacts with alcohols in dehydration synthesis to form ?

A

Glycosides

The new bond is called the glycosidic bond

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11
Q

Is sucrose a reducing sugar?

A

No

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12
Q

Starch and Glycogen are

A

Storage molecules

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13
Q

Chitin and cellulose and

A

structural molecules

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14
Q

The starch phosphorylase reaction claves glucose residues from amylose, producing

A

alpha -D-glucose-1-phosphate

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15
Q

Starch and glycogen consists of what kind of linkages?

A

alpha 1,4

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16
Q

Cellulose consists of what kind of linkages ?

A

Beta 1,4

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17
Q

amylose has what linkage

18
Q

Cellulose strands are ? and chitin strands are ?

A

cellulose =parallel

chitins = can be parallel or antiparallel

19
Q

2 carbons on chitin are

20
Q

One bilayer and thick peptidoglycan outer shell

21
Q

Two bilayers and thin peptidoglycan shell in between the layers

22
Q

pentaglycine bridge connects the tetra peptides

23
Q

direct amide bond between tetra peptides

24
Q

What unique amino acid was pointed out in the tetra peptide chain ?

25
N-linked saccharides are attached via the?
Amide nitirugens of asparagine residues
26
O linked saccharides are attached to
hydroxy groups of serine , threonine or hydroxy lysine
27
Function of O-linked saccharides of glycoproteins
Adopt an extended conformation -these extended conformations resemble "bristle brushes"
28
Bristle brush structure extends functional domains up out of the
glycocalyx
29
Function of N-linked oligosaccharides
alter chem and physical properties of proteins stabilize protein cleavage of units from N linked targets them for degradation in the liver
30
Progressive cleavage of what exposes Gal residues?
Sialic acid Gal exposure increases liver binding
31
proteoglycans are glycoproteins whose carbohydrates are mostly ?
glycosaminoglycans
32
Linear chains of repeating disaccharides
glycosamineglycans
33
Glycosaminoglycans are composed of
proteoglycans
34
Serglycin and decorin are what type of protein?
soluble
35
syndecan is a ? protein
transmembrane
36
Forms the back bone structure of proteoglycans?
hyaluronate
37
proteoglycan consists of a core protein containing ?
O-linked and N-linked glycosaminoglycans
38
N-linked glycoproteins are of three types
high mannose, complex, and hybrid. Hybrid - combines structure found in the complex and high mannose.
39
The carbohydrate groups of proteoglycans are predominantly
glycosaminoglycans )-linked to serine residues.
40
Function of proteoglycans ?
Modulation of cell growth process Cushioning in joints
41
Carbohydrate formula
(CH2O)n