Amino Acid Structure and Peptide Formation

What type of amino acid is aspartic acid?

Which amino acid has an amide group?

What is the 1-letter abbreviation for the amino acid Proline?

Which class of amino acids does Histidine belong to?

What is the 3-letter abbreviation for the amino acid Glutamine?

Which aromatic amino acid has an Indole functional group?

Which functional groups are present in every amino acid?

What is the term given to a peptide chain consisting of 5-9 amino acids?

Which class of amino acids includes glycine?

What is the three-letter abbreviation for threonine?

In a tripeptide, how many possible different combinations can be formed using the 20 standard amino acids?

What is the one-letter abbreviation for methionine?

What main characteristic distinguishes branched-chain amino acids from others?

Which peptide is typically referred to as a protein due to its length?

Amino Acids Classification

Dicarboxylic amino acids: Aspartic acid (Asp, D) and Glutamic acid (Glu, E)
Amino acids with amide group: Asparagine (Asn, N) and Glutamine (Gln, Q)
Dibasic amino acids: Lysine (Lys, K) and Arginine (Arg, R)
Heterocyclic amino acid: Histidine (His, H)
Imino acid: Proline (Pro, P) - also known as Imino acid due to its Pyrrolidine ring structure

Aromatic Amino Acids

Phenylalanine (Phe, F)
Tyrosine (Tyr, Y)
Tryptophan (Try, W)

Structure of Amino Acids

Each amino acid has a core structure consisting of a central carbon atom known as the alpha (α) carbon
Amino acids contain an amino group, a carboxylic group, and a side chain

Formation of Peptide Linkage

Dipeptide: 2 amino acids linked together
Tripeptide: 3 amino acids linked together - can have 20^3 = 8000 different combinations
Tetrapeptide: 4 amino acids linked together
Oligopeptide: 5-9 amino acids linked together
Polypeptide: 10-50 amino acids linked together
Polypeptides with more than 50 amino acids are usually termed as proteins

Simple and Branched-Chain Amino Acids

Simple amino acids: Glycine (Gly, G), Alanine (Ala, A)
Branched-chain amino acids: Valine (Val, V), Leucine (Leu, L), Isoleucine (Ile, I)

Hydroxy and Sulfur-Containing Amino Acids

Hydroxy amino acids: Serine (Ser, S), Threonine (Thr, T)
Sulfur-containing amino acids: Cysteine (Cys, C), Methionine (Met, M)

Learn about the core structure of amino acids, including the alpha carbon, amino group, carboxylic group, and side chain. Understand how peptide linkages are formed and the differences between dipeptides and tripeptides.