Experiment #9: Amines, Amino Acids, And Proteins

Question 1

TERMINOLOGY:

Proteins with 1 peptide chain

Answer 1

Monomeric Proteins

Question 2

*

TERMINOLOGY:

Proteins with more than 1 polypeptide chain

Answer 2

Multimeric Proteins

Question 3

TERMINOLOGY:

Only one kind of polypeptide

Answer 3

Homomultimeric

Question 4

TERMINOLOGY:

Several different kinds of polypeptide chains

Answer 4

Heteromultimeric

Question 5

TERMINOLOGY:

Each amino acid in a peptide

Answer 5

Moiety or Residue

Question 6

TERMINOLOGY:

The residue having a free alpha amino group

Answer 6

n-terminal residue

Question 7

TERMINOLOGY:

The residue having a free carboxyl group

Answer 7

c-terminal residue

Question 8

SOLUBILITY OF AMINES IN WATER:

Small aliphathic amines whose carbon atoms are less than ________ are water soluble and their solutions gave a ____________ (ph less than 7) when tested with litmus paper

Answer 8

1. less than 5
2. basic response

Question 8

TRUE OR FALSE:
Solubility of Amines in Water:

As the number of C atom increase, solubility decreases

Answer 8

TRUE

Question 9

TRUE OR FALSE:
Solubility of Amines in Water:

Although most amines are not water soluble, amine salts are generally water soluble

Answer 9

TRUE

Question 10

TRUE OR FALSE:
Solubility of Amines in Water:

The more substituted or larger is the nonpolar group, the more soluble

Answer 10

FALSE; the more substituted/larger the nonpolar group, the less soluble

Question 11

TRUE OR FALSE:
Solubility of Amines in Water:

The more substituted the compound is, the more basic

Answer 11

TRUE

Question 12

IDENTIFICATION:
Solubility of Amines in Aqueous Acid:

Amines react with acids forming ____________________ ?

Answer 12

positively charged quaternary amines

Question 13

Generally used to detect the presence of free alpha amino groups in amino acids, polypeptides, and proteins

Answer 13

Ninhydrin Test

Question 13

What is the reagent for Ninhydrin Test?

Answer 13

Ninhydrin Solution

Question 14

What is the positive result for Ninhydrin Test?

Answer 14

Appearance of blue to violet colored spots

Question 14

The test is used to detect the presence of two or more peptide linkage in proteins and their larger hydrolytic products (proteoses and peptones)

Answer 14

Biuret Test