Amines, Amino Acids and Proteins Flashcards
are compounds in which one or more of the hydrogen atoms of the ammonia molecule have been replaced by hydrocarbon groups.
Amines
act as Lewis bases and are nucleophiles
Amines
the unshared electron pair on the N atom is responsible for most of the chemical properties of amines
Amines
TRUE OR FALSE:
Amines are classified as 1, 2 or 3 according to the number of hydrogen atoms that have been replaced
TRUE
TRUE OR FALSE:
Amines also make an aromatic ring strongly activated towards electrophilic aromatic substitution (EAS) reactions
TRUE
TRUE OR FALSE:
Amines, whether soluble or insoluble in water, react quantitatively with weak acids to form water-soluble salts.
FALSE; it reacts quantitavely with strong acids
TRUE OR FALSE:
- Amines are non-polar compounds
- Both 1° and 2° amines form intermolecular hydrogen bonds.
- FALSE; they are polar compounds
- TRUE
TRUE OR FALSE:
The acid-base reaction between an amine and water involves transfer of a proton from water to amine.
TRUE
They are the buildings blocks of proteins.
Amino Acids
Each amino acid has a
1. _______
2. _______
3. ________
- Carboxyl Group
- Amino Group
- R Group (distinctive side chain)
TRUE OR FALSE:
In most aa, the amino group is bonded to the C atom which is attached to the carboxyl group
TRUE
TRUE OR FALSE:
there are about 25 different α-amino acids obtained from the hydrolysis of different proteins and they differ only in the nature of the R groups
FALSE; they are only 20 different α-amino acids
TRUE OR FALSE:
In amino acids, the central carbon is surrounded by four different groups and only L-isomer occurs naturally.
TRUE
An absolute configuration; does not indicate the direction by which the molecule rotate plane
polarized light
D and L Configuration
TRUE OR FALSE:
The amino and carboxyl groups in aa undergo external acid-base reaction to form an external salt
FALSE; they undergo internal acid-base reaction to form an internal salt
TRUE OR FALSE:
Amino acids can exist as zwitterions or polar ions
TRUE
TRUE OR FALSE:
Amino acids undergo the same reactions due to the amino and carboxyl groups
TRUE
TRUE OR FALSE:
Similarities in chemical behavior arise when other functional groups are present in the R portion of the molecule
FALSE; Differences in chemical behavior arises
Formed by condensation reaction of amino acids with the removal of
water
Peptides
Complex Nitrogenous Organic Substances involved in all phases of cell metabolism
Proteins
Proteins are very (1. your answer here) and essentially consists of (2. your answer here) long chains which are coiled and folded in a definite number.
- Large
- One or more
In proteins, the individual chains are made up of amino acids which are connected by ____________?
amide linkages or peptide bonds
It yields the component amino acids
Hydrolysis of proteins
TRUE OR FALSE:
Made up of one or more polypeptides folded in specific conformations
TRUE
It is a linear polymer of amino acids.
Polypeptide Chain
TRUE OR FALSE:
Proteins cannot be classified according to function, solubility, composition and shape.
FALSE; it can be classified
4 Levels of Protein Organization:
refers to the manner in which the aa are arranged in space and some protein chains are arranged in the form of α-helix or β-pleated sheet
Secondary Structure
4 Levels of Protein Organization:
The sequential order of aa along the chain which is a characteristic for a given protein
Primary Structure
4 Levels of Protein Organization:
Refers to the manner in which the protein molecule is folded
Tertiary Structure
In tertiary structure, polypeptide chains arranged in long strands or sheets are called __________?
Fibrous
In tertiary structure, polypeptide chains folded into spherical are called __________?
Globular
4 Levels of Protein Organization:
Describes the organization of subunits in a protein with multiple/assembled subunits (oligomeric protein)
Quaternary Structure
The biological activity of a protein depends on its structure
Protein Denaturation
Protein Denaturation is the (1.__________) of protein’s proper conformation and (2.__________) that stabilize the secondary, tertiary, and quaternary structures.
- Destruction
- Disruption of Forces
TRUE OR FALSE:
Protein Denaturation results in changes in chemical properties (precipitation or coagulation) and
loss of biological activity
FALSE; it results in changes in physical properties
TRUE OR FALSE:
Protein Denaturation may be caused by the action of heat, light, chemical agents such as alcohols, strong acids and bases, detergents and heavy metals such as Hg (II) and Pb (II)
TRUE
generally used to detect the presence of free α-amino groups in amino acids, polypeptides and proteins.
Ninhydrin Test
What is the reagent of Ninhydrin Test?
Ninhydrin Solution
What is the positive result of Ninhydrin Test?
Appearance of blue- to violet colored spots due to the formation of diketohydrindamine (DYDA)
Used to detect the presence of two or more peptide linkages in proteins and their larger hydrolytic products (proteoses and peptones).
Biuret Test
What is the reagent for Biuret Test?
Alkaline Copper (II) Sulfate
What is the positive result of Biuret Test?
Formation of violet-colored coordination complex due to the coordination of cupric ions with the unshared electron pairs of the peptide
Sulfur in sulfur-containing proteins and amino acids can be released as sulfides by the action of strong alkali.
Reaction with Lead Acetate
What is the reagent of Reaction with Lead Acetate?
NaOH (sodium hydroxide)
Pb(CH3COO)2 (Lead II Acetate)
It 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.
Protein Denaturation
What is the positive result of Reaction with Lead Acetate?
Formation of Black Precipitate
What is the positive result of Protein Denaturation?
Appearance of Precipitate or Coagulated Product
TRUE OR FALSE:
The sulfides cannot be precipitated by lead acetate
FALSE; it can be precipitated
TRUE OR FALSE:
Protein Denaturation may be caused by the action of heat, light, alcohols, strong acids and bases, and other denaturing agents.
TRUE
What are the samples that we will be using for this experiment?
- diethylamine
- aniline
- N,N-dimethylaniline
- alanine
- casein
- albumin
What are the samples that we will be using for the Solubility of Amines in Aqueous Acid?
- Diethylamine
- Aniline
- N,N - dimethylaniline
What are the measurements and the procedure for the Solubility of Amines in Aqueous Acid?
- Add 5 drops of sample
- 1 mL dH2O
- shake and observe
- Test the acidity using Litmus Paper
- 2.5 mL of concentrated HCl
- shake and observe
What are the measurements and the procedure for the Ninhydrin Test?
- Spot the small on filter paper
- Allow to dry
- Dip in 2% ninhydrin solution in acetone
- Evaporate the solvent
- Allow color to develop
What are the measurements and the procedure for the Biuret Test?
- Place 2mL of sample
- Add 2 mL of NaOH (10%)
- Shake
- Add 1 drop 2% CuSO4 (Copper Sulfate)
- Mix and run a water blank
What are the measurements and the procedure for the Reaction with Lead Acetate Test?
MEASUREMENTS:
* A strand of hair
* 0.5 mL of 20% NaOH
* 1 drop 10% Pb(CH3COO)2
PROCEDURE:
1. Boil the mixture for 5 minutes.
2. Examine and record your observations.
3. Dispose the wastes in properly labeled containers.
What are the measurements and the procedure for the Ninhydrin Test?