Carbohydrates

Question 1

What is the glycome?

Answer 1

total sugars produces in a cell or organism

Question 2

What is a stereoisomer?

Answer 2

two isomers with the same chemical composition but different 3D orientation

Question 3

A chiral centre is …

Answer 3

generally a carbon with 4 different groups bonded to it with a non-superimposable mirror image

Question 4

enantiomer:

how many do chiral carbons with one chiral centre have?

Answer 4

• mirror image configurations that aren’t superimposable on each other
• two

Question 5

epimer:

Answer 5

two sugars that differ only in configuration of one C, require 2+ chiral centres

Question 6

diastereoisomers:

Answer 6

two monosaccharide stereoisomers with two or more differing chiral carbons that are not mirror images

Question 7

anomeric carbon:

Answer 7

epimer at the hemiacetyl/acetyl carbon in cyclic form

Question 8

What is the sugar code?

Answer 8

how sugars inter cellularly code for information

Question 9

the classes of CHO are ___saccharides (one sugar), ___saccharides (two sugars), ___saccharides (3-10 sugars), and ___saccharides (10+ sugars)

Answer 9

mono/di/oligo/poly

Question 10

Sugars are either aldoses (prefix ___-) or ketoses (prefix ___-), they have the suffix -___

Answer 10

Aldo/keto/ose

Question 11

Number of carbons is the middle portion of the name (3=___,4=___,5=___,6=___,7=___)

Answer 11

tri/tetra/penta/hexa/hept

Question 12

When the aldehyde group is ____ in a Fisher projection it determines the configuration, if the -OH is left its ___ (prefix ___-), of its right its ___ (prefix ___-)

Answer 12

on top/levo/L/dextro/D

Question 13

number of stereoisomers=2^___, ___=number of ___

Answer 13

n/n/C

Question 14

enantiomers differ in ___ D/L configuration while epimers differ in ___. Epimers=number of ___-___

Answer 14

every/one/chiral carbons/1

Question 15

in solution, monosaccharides are mostly found as ___ (aldoses) and ___ (ketoses). aldose+___=___, ketose+___=___

Answer 15

hemiacetyls/hemiketals/alcohol/hemiacetyl/alcohol/hemiketal

Question 16

Cyclization:

Answer 16

monosaccharides transition from open chain to ring

Question 17

What is the configuration for α-D-glucopyranose vs. β-D-glucopyranose? when is this difference not visible (in diagram)

Answer 17

• the -OH on the C beside the O is down for α and up for β

- fisher projections

Question 18

a pyran ring is a ___ membered ring (ex. ___) and a furan is a ___ membered ring (ex.___)

Answer 18

6/glucose/5/fructose

Question 19

Fehlings reaction: used to determine free ___ levels in ___ or ___ by qualifying sugars with ___ ends. The ___ oxidize in the presence of a strong oxidizing agent and refusing Cu which causes a colour change from ___ to ___. Why is this not completely accurate for measuring blood glucose?

Answer 19

monosaccharide/blood/urine/reducing/blue/red

Not completely accurate because it only detects monosaccharides with reducing ends (includes galactose)

Question 20

____ provides a good measure of ___-glucose in blood/urine because it’s ___ to glucose, bases on quantification of ____

Answer 20

Glucose oxidase/D/specific/hydrogen peroxide

Question 21

Disaccharides: ___+___=, ___+___=___, ___+___=___

which have reducing ends?

Answer 21

glucose/glucose/maltose (reducing end)
glucose/galactose/lactose (reducing end)
glucose/fructose/sucrose (no reducing end)

Question 22

What is a reducing end?

Answer 22

another name for anomeric carbon- can exist in two forms based on substituent position, generated by ring closure of monosaccharides

Question 23

Polysaccharides are either ___polysaccharides (one monomer) or ___polysaccharides (more than one monomer)

Answer 23

homo/hetero

Question 24

Starch: mixture of two ___polysacchairdes, made up of ___, used as a storage molecule in ___. Either ___ (branched) or ___ (unbranched)

Answer 24

homo/glucose/plants/amylopectin/amylose

Question 25

Glycogen: storage molecule in ___. Primarily located in the ___. Main chain is ___ with ___ every 8-12 residues

Answer 25

animals/liver/glucose/branches

Question 26

___: structural ___polysaccharide, found in the cell wall of plants. Made up of ___, not digestible in humans because of the ___ bonds instead of ___. It is fibrous and water ___.

Answer 26

Cellulose/homo/glucose/β/α/insoluble

Question 27

Unbranched heteropolysaccharides are present commonly in ___ as a ___

Answer 27

bacteria/coating

Question 28

Branches heteropolysaccharides are used to link ___ to carbs, making them ___ PRO, ___ PRO, and play a role in folding

Answer 28

PRO/surface/receptor

Question 29

What are the two types of linked oligosaccharide additions?

Answer 29

N-linked oligosaccharides and O-linked oligosaccharides

Question 30

Freeness of anomeric carbons in ___saccharides:

maltose: ___ free ___not free (___ total)
lactose: ___ free ___not free (___ total)
trehalose: ___ free ___not free (___ total)
sucrose: ___ free ___not free (___ total)

Answer 30

di
1/1/2
1/1/2
0/2/2
0/1/1