FSQ drills - biological molecules - OCHEM

Question 1

How many carbons are in a glucose ring?

Answer 1

The ring contains 5 carbons, but a 6th carbon comes off of the ring making it a 6 carbon molecule

Question 2

What is a hemiacetal

Answer 2

A molecule that contains an alcohol and an ether attached to the same carbon

Question 3

Why can’t Proline act as a hydrogen bond donor when it is in the middle of a polypeptide sequence?

Answer 3

Proline forms a hydrogen bond between its side chain and its amino group, so this eliminates the extra hydrogen that amino acids have available in their amino group for hydrogen bonding

Question 4

What reaction causes the formation of a disulfide bond between cystine residues?

Answer 4

Oxidation reaction

Question 5

What is the state of an acidic side chain at the physiological pH?

Answer 5

At the physiological pH of 7.4 acidic side chains are deprotonated (causing them to be negatively charged) and the basic side chains are protonated (causing them to be positively charged)

Question 6

What kind of amino acid is aspartic acid?

Answer 6

An acidic amino acid

Question 7

What kind of amino acid is arginine?

Answer 7

Arginine is a basic amino acid

Question 8

All sugar stereocenters with the OH group on the right of a Fischer projection will have what configuration?

Answer 8

They will have an R configuration

Question 9

What are epimers?

Answer 9

Epimers are stereoisomers that differ at exactly ONE stereocenter

Question 10

What does the Benedicts reagent react with?

Answer 10

Carbonyl functional group