Amino Acids

What are the four components of an amino acid?

Carboxyl group, R group, hydrogen, and an amino group.

What is a zwitterionic molecule?

A neutral molecule with both positive and negative charges at physiological pH.

Which amino acid has no hydrocarbon side chain?

Glycine.

What is the role of proline in proteins?

It forms a rigid ring structure that adds rigidity to proteins.

What defines uncharged polar side chains?

They are zwitterionic with zero net charge at physiological pH and are hydrophilic.

Which amino acids are targets of phosphorylation by kinase enzymes?

Serine, Threonine, and Tyrosine.

What is the net charge of acidic side chains?

Negative net charge.

Which amino acids are classified as acidic?

Aspartic acid (Asp) and Glutamic acid (Glu).

What is the net charge of basic polar side chains?

Net positive charge.

Which amino acids are classified as basic?

Histidine (His), Lysine (Lys), and Arginine (Arg).

What type of bond stabilizes the tertiary structure of proteins?

Disulfide bonds, hydrogen bonds, hydrophobic interactions, and ionic interactions.

What is the primary protein structure?

The amino acid sequence of a protein.

What stabilizes the secondary protein structure?

Hydrogen bonds between the -NH and C=O groups of two peptide bonds.

What are motifs in protein structure?

Combining multiple secondary structures to produce recognizable structures within a globular protein.

What is the role of chaperone proteins?

They aid in the proper folding of proteins.

What is quaternary protein structure?

The arrangement of multiple polypeptides into a complex.

What can cause abnormal protein folding?

Mutations that alter the primary amino acid sequence.

What is amyloid formation?

The process where normal well-folded proteins form large protein structures that can be damaging.

What is the difference between human insulin and insulin glargine?

Human insulin has a net negative charge, while insulin glargine is modified to be more neutral and hydrophobic.

What is the consequence of a mutation from Glu to Val in sickle cell disease?

It causes a hydrophobic pocket in the B globin subunit, leading to sickling of red blood cells.

What is the significance of hydrophobic interactions in protein folding?

Nonpolar hydrophobic amino acids move into the interior of globular proteins in an aqueous solution.

What is the configuration of peptide bonds in proteins?

Peptide bonds are rigid and planar, with trans configuration having R groups on opposite sides.

What stabilizes beta sheets in protein structure?

Hydrogen bonding between at least two beta strands.

What is the role of charged amino acids in protein interactions?

They can form ionic bonds or electrostatically repel one another.

What are the non-polar amino acids

glycine and proline

What are the uncharged polar amino acids

serine, threonine, tyrosine, asparagine, glutamine, and cysteine

What stabilizes a quaternary structure

Noncovalent interactions such as hydrophobic interactions, hydrogen bonds, and ionic bonds