Lecture 15

Question 1

monosacs- two types

Answer 1

aldoses and ketoses

at least two hydroxyl
groups (CH2O)n

Question 2

aldoses

Answer 2

carbonyl group comes at the end of the chain and thus represents an aldehyde group

Question 3

ketoses

Answer 3

carbonyl group occurs within the chain and hence represents a ketone group

Question 4

enatiomers

Answer 4

stereoisomers that are nonsuperimposable mirror images of eachother

Question 5

diastereomers

Answer 5

Diastereomerism occurs when two or more stereoisomers of a compound have different configurations at one or more (but not all) of the equivalent (related) stereocenters and are not mirror images of each other.

Question 6

Carbohydrates

Answer 6

Primary energy source in bread, rice and pasta

• They do not catalyze reactions.
• They do not replicate.
• They serve as signals on cells.
• They are important fuels.
• They taste good.

Question 7

Glyceraldehyde

Answer 7

is the smallest aldose

Question 8

D or L more common?

Answer 8

D

Question 9

Epimers

Answer 9

differ from each other at just one asymmetric carbon

Question 10

Dihydroxyacetone

Answer 10

is the smallest ketose

• No asymmetric carbons.

Question 11

Ketoses

Answer 11

have 1 fewer asymmetric carbons than aldoses

Ketoses often use the same root names as aldoses but with a“ul” included in the middle of the name.

Question 12

anomeric

Answer 12

The carbonyl carbon becomes the “anomeric” carbon

α means opposite CH2OH (carbon 6)

β means same side as CH2OH (carbon 6)

Question 13

Glycosidic bonds

Answer 13

form when an anomeric carbon reacts with an alcohol

Question 14

galactose and glucose relationship

Answer 14

epimers

Question 15

non-reducing

Answer 15

This cannot form a free aldehyde or ketone

so it is called a non-reducing sugar

Question 16

Maillard Reaction

Answer 16

Reaction of reactive carbonyl of the open forms reducing sugars with nucleophilic amino groups of amino acids at high temperature to
produce a complex mixture of substances.

Question 17

Hemoglobin A1c:

Answer 17

N-fructosyl-valine Hemoglobin

High levels of HbA1c are a
reliable indicator of diabetes.

Question 18

Polysaccharides

Answer 18

Cellulose, chitin, glycogen, starch

Question 19

cellulose

Answer 19

glucose+ glucose

Wood, white cotton and paper are almost pure cellulose.
We cannot digest cellulose. Estimated 1015 kg of
cellulose is synthesized and degraded on earth
annually!!

Question 20

EM of cell wall of green algae..shows rigid long cellulose fibrils.

Answer 20

Who can digest cellulose?
•Cows (rumen full of bacteria)
•Termites (endogenous and bacterial
cellulase)
•Biofuel companies (make cellulosic ethanol starting with fungal cellulases or acid treatment)

Question 21

chitin

Answer 21

next to cellulose, chitin is the second most abundant polysaccharide in nature

Question 22

amylose

Answer 22

this type of helix cannot form when there are branches

Question 23

cellulose

Answer 23

β-D 1,4

Question 24

Unbranched Starch – α amylose

Answer 24

Starch is insoluble in water and must be broken down by pancreatic amylases.

Question 25

amylopectin

Answer 25

can be up to 10^6 glucose residues
α (1–>6) branch point
(one every 24-30 residues)

Question 26

HIGH FRUCTOSE CORN SYRUP

Answer 26

cornstarch ~7-% amylopectin –> (α-amylase) —> Oligosaccharides of glucose —> (glucoamylase) –> glucose –> (glucose isomerase) —> glucose (42%) & fructose (55%)

“HFCS 55”

Question 27

Glycogen

Answer 27

stored glucose in muscle and liver.
More branched than starch.
Glucose can be released starting at non-reducing ends.

(one every 8-14 residues)