Amines, Amino Acids and Protein

Question 1

_________are compounds in which one or more of the hydrogen atoms of the ammonia molecule have been replaced by hydrocarbon groups.

Answer 1

Amines

Question 2

____________ are classified as 1, 2 or 3 according to the number of hydrogen atoms that have been replaced

Answer 2

Amines

Question 3

• the unshared electron pair on the N atom is responsible for most of the chemical properties of amines
• It act as Lewis bases and are nucleophiles
• It also make an aromatic ring strongly activated towards electrophilic aromatic substitution (EAS) reactions

Answer 3

Amines

Question 4

They are polar compounds, and both 1° and 2° amines form
intermolecular hydrogen bond

Answer 4

Amines

Question 5

Proteins with only 1 peptide chain. (Tertiary Structure)

Answer 5

Monomeric proteins

Question 6

Proteins with more than 1 polypeptide chain. (Quaternary Peptides)

Answer 6

Multimeric Proteins

Question 7

only one kind of polypeptide

Answer 7

Homomultimeric

Question 8

Several different kinds of polypeptide chains

Answer 8

Heteromultimeric

Question 9

Each amino acid in a peptide

Answer 9

Moiety or Residue

Question 10

The residue has a free a-amino group. The 1st amino acid in the sequence

Answer 10

N-terminal residue

Question 11

The residue has a free carboxyl group.

Answer 11

C-terminal residue

Question 12

• They are basic compounds
• Small aliphatic amines (< 5C) are water-soluble and their solutions give a basic response (pH>7) when tested with litmus paper

Answer 12

Solubility of Amines in Water

Question 13

• As the number of C atoms increases, solubility decreases
• Although most amines are not-soluble, amine salts are generally water soluble

Answer 13

Solubility of Amines in Water

Question 14

• More substituted or the larger the nonpolar group, the less soluble the sample is.
• The more substituted, the more basic

Answer 14

Solubility of Amines in Water

Question 15

It depends on the side chain

Answer 15

Amino acids

Question 16

Solubility in 6M HCl is a positive identification test for bases. Amines that are insoluble in pure water will be soluble in acid due to the formation of an ammonium chloride salt.

Answer 16

Solubility of Amines in Aqueous Acid

Question 17

In solubility of Amines in Water, ________ are readily protonated by strong acids such as HCL and H2SO4.
- _______ react with acids forming positively charge quaternary amines

Answer 17

Amines

Question 18

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

Answer 18

Ninhydrin Test

Question 19

Reagent - Ninhydrin Solution

Answer 19

Ninhydrin Test

Question 20

Positive Result: Appearance of blue to violet colored spot due to the formation of diketohydrindamine (DYDA)

Answer 20

Ninhydrin Test

Question 21

____________, whether soluble or insoluble in water, react quantitatively with
strong acids to form water-soluble salts.

Answer 21

amines

Question 22

-__________are the building blocks of proteins.
- Each ___________ has a carboxyl group, an amino group, and a
distinctive side chain (R-group) bonded to the ∝-carbon

Answer 22

Amino acid

Question 23

there are about ___ different α-amino acids obtained from the hydrolysis of
different proteins and they differ only in the nature of the R groups

Answer 23

20

Question 24

• absolute configuration
• It does not indicate the direction by which the molecule rotate plane
  polarized light

Answer 24

D and L configuration

Question 25

The _______ and _________in aa undergo internal acid-base reaction to form an internal salt

Answer 25

amino and carboxyl groups

Question 26

amino acids can exist as _________ or polar ions:

Answer 26

zwitterions

Question 27

It formed by condensation reaction of amino acids with the removal of water

Answer 27

Peptides

Question 28

- They are complex nitrogenous organic substances involved in all phases of cell metabolism - They very large and essentially consist of one or more long chains which are coiled and folded in a definite number

Answer 28

Proteins

Question 29

- Its individual chains are made up of amino acids which are connected by amide linkages or peptide bonds. - Hydrolysis of proteins yields the component amino acids

Answer 29

Proteins

Question 30

It was made up of one or more polypeptides folded in specific conformations

Answer 30

Protein

Question 31

_____________ is a linear polymer of amino acids.

Answer 31

Polypeptide chain

Question 32

The sequential order of aa along the chain is a characteristic for a given protein. (N-terminal and C-terminal)

Answer 32

Primary Structure

Question 33

- refers to the manner in which the aa are arranged in space - some protein chains are arranged in the form of α-helix or β-pleated sheet

Answer 33

Secondary Structure

Question 34

- It refers to the manner in which the protein molecule is folded - polypeptide chains arranged in long strands or sheets (fibrous) - polypeptide chains folded into spherical or globular shape (globular)

Answer 34

Tertiary Structure

Question 35

It describes the organization of subunits in a protein with multiple subunits (oligomeric protein)

Answer 35

Quaternary Structure

Question 36

- the biological activity of a protein depends on its structure - destruction of protein’s proper conformation - disruption of forces that stabilize the 2, 3 and 4 structures

Answer 36

Protein Denaturation

Question 37

- Results in changes in physical properties (precipitation or coagulation) and loss of biological activity - It may be caused by the action of heat, light, and chemical agents such as alcohols, strong acids and bases, detergents, and heavy metals such as Hg (II) and Pb (II)

Answer 37

Protein Denaturation

Question 38

It is used to detect the presence of two or more peptide linkages in proteins and their larger hydrolytic products (proteoses and peptones).

Answer 38

Biuret Test

Question 39

Reagent: alkaline copper (II) sulfate

Answer 39

Biuret Test

Question 40

(+) result: formation of violet-colored coordination complex due to the coordination of cupric ions with the unshared electron pairs of the peptide

Answer 40

Biuret Test

Question 41

Sulfur in sulfur-containing proteins and amino acids can be released as sulfides by the action of strong alkali. - the sulfides can be precipitated by lead acetate

Answer 41

Reaction with Lead Acetate

Question 42

Reagent: NaOH/Pb(CH3 COO)

Answer 42

Reaction with Lead Acetate

Question 43

(+) result: Formation of black precipitate

Answer 43

Reaction with Lead Acetate

Question 44

____________ is associated with the alteration of the secondary and tertiary structures of biological proteins which results in changes in physical properties and loss of biological activity.

Answer 44

Protein Denaturation

Question 45

- May be caused by the action of heat, light, alcohols, strong acids and bases, and other denaturing agents.

Answer 45

Protein Denaturation

Question 46

(+) result: appearance of precipitate or coagulated product

Answer 46

Protein Denaturation

Question 47

Treatment of amine with benzesulfonyl in aqueous sodium hydroxide and then acidified with HCL

Answer 47

Hinsberg Test

Question 48

Addition of Hinsberg Solution in primary amines will results to

Answer 48

clear solution (+)

Question 49

Addition of Hinsberg Solution in secondary amines will results to

Answer 49

suspension or oil formation (-)

Question 50

Addition of Hinsberg Solution in tertiary amines will results to

Answer 50

suspension or oil formation (-)

Question 51

Addition of HCL to 1 amines will results to

Answer 51

appearance of precipitate

Question 52

Addition of HCL to 2 amines will results to

Answer 52

suspension or oil formation

Question 53

Addition of HCL to 3 amines will results to

Answer 53

clear solution