Lecture 19, Carbohydrates (Ford)

Question 1

In constitutional isomers, what changes?

Answer 1

Order of atoms

Question 2

T or F: Constitutional isomers are tautomers.

Answer 2

True.

Question 3

In a tautomer, where does carbon numbering start?

Answer 3

Carbonyl end of the aldose

Question 4

Fisher projections are the ___ versions of carbohydrates.

Answer 4

Linear

Question 5

Describe stereoisomers.

Answer 5

Same connectivity, different spatial organizations

Question 6

What kind of carbons do configurational isomers have?

Answer 6

Chiral

Question 7

Describe enantiomers.

Answer 7

Mirror images at all chiral centers

Question 8

T or F: Diastereomers can have only 1 chiral center, as long as the images do not mirror one another.

Answer 8

False. Diastereomers must have multiple chiral centers.

Question 9

Describe diastereomers.

Answer 9

Not mirror images overal

Question 10

Hawthorne projections are the ___ versions of carbohydrates.

Answer 10

Cyclical

Question 11

Outline how to convert a monosaccharide from a Fisher to a Hawthorne projection.

Answer 11

1. Choose the ring
2. Carbonyl C goes 1 position CW from the O
3. Number C CW
4. =O becomes OH
5. Left side goes up, right side goes down

Question 12

When converting from a Fisher to a Hawthorne projection, what do beta and alpha signify when the =O becomes an OH?

Answer 12

Beta = up
Alpha = down

Question 13

How do anomers differ?

Answer 13

At anomeric C only

Question 14

How do epimers differ?

Answer 14

At any other C than the anomeric C

Question 15

What kind of rotation changes do conformational isomers have?

Answer 15

Reversible rotation changes

Question 16

List the monosaccharides to know.

Answer 16

Glyceraldehyde, ribose, glucose, galactose, dihydroxyacetone, ribulose, fructose, D-deoxyribose, D-mannose

Question 17

When are glycosides formed?

Answer 17

When one or more hydroxyls are replaced

Question 18

What can hydroxyls be replaced with to form a glycoside?

Answer 18

Fucose, esters (phosphorylation), oxidation/reduction (alcohols), N-linkages (amino sugars, nucleotides), O-linkages (methylation, toxins)

Question 19

Why is fucose weird?

Answer 19

Galactose derivative; only L-monosaccharide made and used by mammals; part of A/B/O blood antigens

Question 20

What can excess fucose in the blood lead to?

Answer 20

Liver damage, cancer, diabetes, heart disease

Question 21

Describe how monosaccharides can be modified via phosphorylation.

Answer 21

Important reactive intermediates in carbohydrate metabolism, adds negative charge, phosphate from ATP

Question 22

What is the relationship between a monosaccharide and a phosphate modification?

Answer 22

Name of monosaccharide tells you where to put the phosphate

Question 23

What kind of linkages do phosphates have?

Answer 23

Ester

Question 24

Where are reducing sugars oxidized in monosaccharides?

Answer 24

Carbonyl

Question 25

What does the oxidation of a monosaccharide make?

Answer 25

Acids and lactones

Question 26

What does the reduction of a monosaccharide make?

Answer 26

Alditols

Question 27

What can cause cataracts if it accumulates in the lens of the eye?

Answer 27

Sorbitol (reduction of carbonyl)

Question 28

Where are monosaccharides that are modified with amino sugars found?

Answer 28

In branched polysaccharides (like cell walls)

Question 29

List the essential, regular monosaccharides.

Answer 29

D-glucose, D-galactose, D-mannose, D-xylose

Question 30

Of the essential monosaccharides, which is the oddball?

Answer 30

L-fucose

Question 31

Of the essential monosaccharides, which are amino sugars?

Answer 31

GlcNAc, GalNAc, sialic acid

Question 32

List the essential monosaccharides.

Answer 32

D-glucose, D-galactose, D-mannose, D-xylose, L-fucose, GlcNAc, GalNAc, sialic acid

Question 33

List the roles of polysaccharides.

Answer 33

Glucose storage, structure, protein diversity

Question 34

Which structural polysaccharide is essentially universal?

Answer 34

Chitin

Question 35

List how polysaccharides create protein diversity.

Answer 35

Glycoproteins, glycosaminoglycans, mucins

Question 36

T or F: In glycoproteins, protein < sugar.

Answer 36

False. In glycoproteins, protein > sugar.

Question 37

What are glycoproteins called on membrane and soluble proteins?

Answer 37

``` Membrane = cell adhesion Soluble = cell signaling ```

Question 38

T or F: In glycosaminoglycans, sugar < protein.

Answer 38

False. In glycosaminoglycans, sugar > protein.

Question 39

Describe the structure of glycosaminoglycans.

Answer 39

Repeating disaccharide units, sugar component of proteoglycans (cartilage, blood clotting, chitin)

Question 40

In mucins, sugar ___ protein.

Answer 40

>

Question 41

What do mucins provide?

Answer 41

Lubrication (protection, hydration)

Question 42

How are glycolipids related to blood type?

Answer 42

Decorate cell membranes and are used to recognize self/other