Carbohydrates

Question 1

Carbohydrate

Answer 1

(CH2O)n

- aldehyde or ketone derivative of a polyhydroxyl compound.

Question 2

Isomer

Answer 2

molecules with identical molecular formula but different structures

Question 3

Enantiomer

Answer 3

differ in configuration around one chiral carbon.

• mirror images (D or L)
• living systems contain D carbohydrates

Question 4

Epimer

Answer 4

one of two optical isomers that differ from each other only in configuration about one asymmetric carbon atom

• during cyclization
• alpha or beta

Question 5

Diasteromer

Answer 5

one of 2 or more optical isomers of a compound that are not enantomers

Question 6

Furanose rings assume what form

Answer 6

envelope

- C-2 or c-3 is out of plane on the same side as C5

Question 7

Hydroxyl groups attach through

Answer 7

O-glycosidic bonds.

Question 8

Amine groups attach

Answer 8

through N-linked glycosidic bonds

Question 9

Reducing Sugars

Answer 9

free aldehyde group are capable of forming an aldehyde through ring opening, isomerization or tautomerization

Question 10

Test for reducing sugars

Answer 10

• Benedicts reagent
• Fehlings solution
• tollens tet

Question 11

Connecting Monosaccharide by glycosidic bonds

Answer 11

Glycosidic bond: connects monomers into dimmers, trimer,s, oligosaccharides or polysaccharides

• condensation (dehydration) reaction
• orientation alpha and beta

Question 12

What is the function of maltose, lactose, sucrose?

Answer 12

Maltose: break down product of glycogen/starch

lactose: mammals milk sugar
sucrose: table sugar

Question 13

glycogen

Answer 13

glucose connected alpha 1,4- with alpha 1,6 branches

• animal storage
• stored in liver and muscle

Question 14

starch

Answer 14

glucose connected alpha 1,4 with 1,6 branches storage

-plant storage

Question 15

cellulose

Answer 15

glucose connected beta-1,4 linear

-plant structural fiber

Question 16

O antigen group

Answer 16

contain 4 carbohydrates

-modified to A and B antigens

Question 17

A antigen

Answer 17

N-acetylgalactosamine

Question 18

B

Answer 18

added to galactose

Question 19

Protein modification of N-linked carbohydrates

Answer 19

are attached to r group of asparagine

Question 20

O linked carbohydrates are attached

Answer 20

to R group of serine or threonine.

Question 21

erythropoietin has how many sugar modification sites?

Answer 21

three N-linked groups

-1 O linked

Question 22

Where does N-linked carbohydrate attached/modified and O-linked carbohydrates

Answer 22

• on a dolichol phosphate in the ER

- golgi and cytoplasm

Question 23

Errors in glycosylation may lead to I-cell disease how?

Answer 23

• improper target of digestive enzymes to lysosomes

- N-linked glycoyl group is not phosphorylated

Question 24

Lectin

Answer 24

Specific carbohydrate binding proteins

-cell to cell interaction

Question 25

Digestion of carbohydrate

Answer 25

Mouth: mixes salivary alpha amylase with dietary starch

• stomach: digestion halts due to low pH
• small intestine: acid neutralized by bicarbonate and alpha amylase from pancreas
• mucosal lining of upper jejunum: disaccharidases, oligosaccharidases (isomaltase, maltase, sucrase)