Carbohydrate SLO's

Question 1

• List the characteristics that define carbohydrates.

Answer 1

Saccharides are the most abundant biological molecules. They are chemically simpler than nucleotides or amino acids. made of just carbon, hydrogen and oxygen

Question 2

How to determine chiral centers?

Answer 2

Number of carbons excluding the first and last carbon on chain

Question 3

Define Isomers

Answer 3

Same molecular formula but different arrangement of atoms

Question 4

Define constitutional isomers

Answer 4

Same molecular formula but different structural formulas

Question 5

Define stereoisomers

Answer 5

that have the same composition (that is, the same parts) but that differ in the orientation of those parts in space. There are two kinds of stereoisomers: enantiomers and diastereomers

Question 6

Define enantiomers

Answer 6

Are mirror images

Question 7

Define diastereoisomers

Answer 7

are the stereomer compounds with molecules that are not mirrored images of one another and that are not superimposable.

Question 8

Define epimer

Answer 8

differ at one carbon

Question 9

Define anomer

Answer 9

differ in configuration at anomeric carbon

Question 10

how to determine if a monosaccharide is in a D or L configuration?

Answer 10

D- OH is on same side as CH2OH

L- OH is on different side as CH2OH

Question 11

• From a Haworth projection, be able to determine if a sugar is an alpha or beta anomer

Answer 11

Beta anomer OH points up

Alpha anomer OH points down

Question 12

What is a hemiacetal?

Answer 12

A hemiacetal forms when an aldehyde reacts with an alcohol

Question 13

What is a hemiketal?

Answer 13

any of a class of compounds characterized by the grouping C(OH)(OR) where R is an alkyl group and usually formed as intermediates in the preparation of acetals from aldehydes or ketones.

Question 14

How to determine is a sugar is a reducing sugar?

Answer 14

are sugars where the anomeric carbon has an OH group attached that can reduce other compounds. All monosaccharides are reducing

Question 15

How to determine if a sugar is non-reducing?

Answer 15

do not have an OH group attached to the anomeric carbon so they cannot reduce other compounds.

Question 16

Define sugar acids and identify

Answer 16

-Oxidation of an aldose converts its aldehyde group to a carboxylic acid (Aldonic acid)
-Oxidation of the primary alcohol
group of aldoses creates uronic acids (Named by adding suffix –uronic to
the root name of the parent aldose)

Question 17

Define and recognize sugar alcohols

Answer 17

chemically defined as saccharide derivatives in which a ketone or aldehyde group is replaced by a hydroxyl group

Question 18

Define Deoxysugars

Answer 18

-OH is replaces with an H on 2nd carbon

Question 19

Define Amino sugars

Answer 19

-OH group replaced by an amino group on 2nd carbon

Question 20

• Be able to link monosaccharides together through an alpha or beta linkage and label the glycosidic bond.

Answer 20

Question 21

• Define homopolysaccharide, heteropolysaccharide, branched and unbranched polysaccharides

Answer 21

A typical homopolysaccharides is defined to have only one type of monosaccharide. units in the chain; whereas, a heteropolysaccharide is composed of two or more types of monosaccharides.

Question 22

• Be able to describe and recognize the structures of cellulose

Answer 22

It is made up of unbranched chains of glucose molecules linked via beta 1-4 glycosidic bonds. Every alternate glucose molecule in cellulose chains is inverted. These chains are arranged parallel to each other to form microfibrils.

Question 23

• Be able to describe and recognize the structures of chitin

Answer 23

Found in exoskeletons of
crustaceans, insects and
spiders, and cell walls of
fungi
■ Similar to cellulose, but
C-2s are N-acetyl

Question 24

• Be able to describe and recognize the structures of amylose, amylopectin

Answer 24

Starches
Glucose storage in plants
■ Two forms: amylose and amylopectin
■ Amylose has α(1,4) links, one reducing end
■ Branches in amylopectin are α(1,6) every 12-30
residues

Question 25

• Be able to describe and recognize the structures of glycogen

Answer 25

Glucose storage in
animals
■ 10% of liver mass and 1- 2% of muscle mass
■ Similar to amylopectin
■ Alpha (1, 4) linkages in
chain
■ alpha(1,6) branches
every 8-12 residues

Question 26

• Define glycosaminoglycans and their functions

Answer 26

• Linear chains of repeating disaccharides
• Alternating uronic acid and hexoamines
• One or both are negatively charged
Functions
Heparin - a natural anticoagulant
■ Hyaluronates - the vitreous humor and synovial fluid
■ Chondroitins and keratan sulfate - tendons, cartilage,
and other connective tissue
■ Dermatan sulfate - extracellular matrix of skin

Question 27

• Describe the difference between an O-linked and N-linked glycoproteins

Answer 27

O-linked saccharides are attached to hydroxyl group of serine or
threonine
N-linked saccharides are attached via the amide nitrogen of
asparagine residues

Question 28

• Give the cellular location of glycosylation in cells

Answer 28

Occurs primarily in ER and Golgi

Question 29

• Describe peptidoglycan and how it pertains to bacterial cell walls

Answer 29

Glycoproteins whose carbohydrates are mostly glycosaminoglycans O-linked to serine residues
■ Soluble proteins and integral membrane proteins (glycocalyx)
-It helps protect bacterial cells from environmental stress and helps preserve cell morphology throughout their life cycle. Peptidoglycan biosynthesis is also an important regulator of bacterial cell division.