Carbohydrates

Question 1

What is the most abundant biomolecule on earth

Answer 1

sugars

Question 2

What is an example of a part of the body that relies ONLY on sugar for energy

Answer 2

the brain

Question 3

Sugars are essential components of….. (think DNA and RNA)

Answer 3

nucleic acids

Question 4

Differentiate between mono, di, oligo, and polysaccharides

Answer 4

mono=1
di=2
oligo=3-19 (short)
poly=20 or more (long)

Question 5

What is an important chemical property of monosaccharides

Answer 5

very water soluble (opposite to lipids)

Question 6

What is the formula for monosaccharides

Answer 6

(CH2O)n

Question 7

What two chemical functional groups are required in the structure of monosaccharides

Answer 7

carbonyl (aldehyde or ketone)
hydroxyl groups (at least 2)

Question 8

Draw the structure of glyceraldehyde (aldose) and dihydroxyacetone (ketose)

Answer 8

on slide 43 of second half lectures 1-4

Question 8

What is the simplest class of monosaccharides

Answer 8

triodes (3 carbons)

Question 9

What class of monosaccharides are the most common in nature

Answer 9

hexoses

Question 10

Much of our understanding of carb chemistry goes back to what scientist

Answer 10

Emil Fischer

Question 11

What does it mean to be an enantiomer

Answer 11

mirror image of one another

Question 12

What is identical between enantiomers

Answer 12

chemical properties

Question 13

What is different between enantiomers

Answer 13

optical activity

Question 14

What are diastereomers

Answer 14

when handedness at some carbons differ and some do not

Question 15

What is different about diastereomers

Answer 15

chemical properties and optical activity

Question 16

How do you identify between D and L sugars

Answer 16

D sugars is if the chiral carbon atom furthest away from the carbonyl has the same configuration as D-glyceraldehyde
L sugars is if the configuration resembles L-glyceraldehyde

Question 17

Most (but not all) naturally occurring sugars are what configuration (D or L)

Answer 17

D

Question 18

What are epimers

Answer 18

when the sugars are identical at all carbons except for one
special case of diastereomers

Question 19

What is the formula to determine the number of stereoisomers in a sugar

Answer 19

2^n (where n is the number of chiral carbons)
- half of the stereoisomers will be D and half will be L

Question 20

What is the relationship between every time a carbon is added and number of isomers

Answer 20

every 1 carbon that’s added, isomers double

Question 21

Aldehyde + alcohol =

Answer 21

hemiacetal

Question 22

Ketone + alcohol =

Answer 22

hemiketal

Question 23

The hemiacetal and hemiketal formations turn sugars into….

Answer 23

rings

Question 24

What is the term for when hemiacetal and hemiketals turn sugars into rings

Answer 24

cyclization of sugars

Question 25

What is the term for ring-structured sugars that only differ at the anomeric carbon

Answer 25

anomers

Question 26

What is an example of anomers

Answer 26

a-glucose and b-glucose

Question 27

When dissolved in water, glucose converts into an equal distribution of alpha, beta, and linear forms; what is this process called

Answer 27

mutarotation

Question 28

In mutarotation, what is the effect on optical properties

Answer 28

they are identical

Question 29

What is a pyranose

Answer 29

a 6-C ring

Question 30

What is a furanose

Answer 30

a 5-C ring

Question 31

If the OH is above in the Haworth formation, glucose is....

Answer 31

beta (left in Fischer formula)

Question 32

If the OH is below in the Haworth formation, glucose is....

Answer 32

alpha (right in Fischer formula)

Question 33

The carbonyl carbon is always the ______________ in the cyclization reaction

Answer 33

electrophile

Question 34

If a sugar turned from blue to red with the addition of cuprous ion (Cu2+) what does this mean

Answer 34

reducing sugar

Question 35

What does it mean to be a reducing sugar

Answer 35

reacts with oxidants

Question 36

What is a glycoside

Answer 36

condensation of the anomeric carbon (acting as electrophile) has occurred with nucleophilic OH or NH creating a molecule called a glycoside

Question 37

What is a glycosidic bond

Answer 37

when the anomeric carbon reacts with the OH of an alcohol

Question 38

What is a glycosilic bond

Answer 38

when the anomeric carbon reacts with the NH group of an amine

Question 39

If the anomeric carbon is involved in a glycosidic bond, the sugar becomes a...

Answer 39

non-reducing sugar why: because the sugar can no longer open up to assume its linear form (only open chain forms of sugar can undergo oxidation)

Question 40

How are dissacharides formed

Answer 40

two monosaccharides are linked through a glycosidic bond

Question 41

Are disaccharides glycosides?

Answer 41

yes

Question 42

How are disaccharides named in terms of their glycosidic bond

Answer 42

anomeric carbon is in either alpha or beta configuration, reacting with the hydroxyl group on a certain carbon of the other sugar for example; the glycosidic bond of lactose is between beta anomeric carbon 1, and the hydroxyl group on carbon 4: would be called (b1-4)

Question 43

If one anomeric carbon is still free to undergo mutarotation in a disaccharide, is this molecule a reducing or nonreducing sugar

Answer 43

reducing (the end not involved in the glycosidic bond is known as the reducing end)

Question 44

What is a double headed sugar

Answer 44

when both anomeric carbons are used in the glycosidic bond (non reducing)

Question 45

Polysaccharides are often highly ______________

Answer 45

branched

Question 46

What are homopolysaccharides

Answer 46

made from a single type of sugar unit

Question 47

What are heteropolysaccharides

Answer 47

made from two or more kinds of sugar subunit

Question 48

What are glucans

Answer 48

glucose homopolymers

Question 49

What are mannans

Answer 49

mannose homopolymers