W - BIOL200 - 2.1 PROTEINS

What are the monomers of proteins?

Amino acids.

What are the 3 parts of an amino acid?

Amino group, carboxyl group, R group.

How many R groups exist?

20 different R groups.

What do R group interactions determine?

The 3D structure of proteins.

What are the types of R group properties?

Hydrophobic, positively charged, negatively charged, or special cases.

Name 3 amino acids with positive side chains.

Arginine, Histidine, Lysine.

Name 2 amino acids with negative side chains.

Aspartic acid, Glutamic acid.

Name 4 polar uncharged amino acids.

Serine, Threonine, Asparagine, Glutamine.

Name 4 hydrophobic amino acids.

Alanine, Valine, Leucine, Isoleucine.

Name 2 special case amino acids.

Proline, Glycine.

How are amino acids linked together?

By dehydration (condensation) reactions.

What bond is formed between amino acids?

Peptide bond.

Which groups form a peptide bond?

Carboxyl group of one amino acid and amino group of another.

What is the repeating backbone in a protein?

N–C–C.

What is the N-terminus of a protein?

The end with the amino group.

What is the C-terminus of a protein?

The end with the carboxyl group.

What is primary protein structure?

Sequence of amino acids.

What is secondary protein structure?

Hydrogen bonds forming alpha-helices or beta-sheets.

What is tertiary structure?

Interactions between R groups.

What is quaternary structure?

Interactions between multiple folded proteins.

What do enzymes do?

Speed up reactions (e.g., lactase breaks down lactose).

What is the transport function of proteins?

Move things across membranes (e.g., ion channels).

What is the support function?

Maintain structure (e.g., cytoskeleton).

What do signaling proteins do?

Communicate (e.g., insulin).

How do proteins help movement?

Move cells or parts of cells (e.g., cilia).

What is the defense function?

Immune protection (e.g., antibodies).

What determines protein folding shape?

Amino acid sequence and side group interactions.

What helps fold proteins properly?

Chaperones.

What happens when proteins lose their shape?

They become denatured.

Does the amino acid sequence change during denaturation?

No.

What bonds are found in protein structures?

• Primary: covalent (peptide) bonds

• Secondary: hydrogen bonds

• Tertiary: hydrogen, disulfide, ionic, Van der Waals

• Quaternary: same as tertiary

What are the building blocks of proteins?

An R group, a carboxyl group, and an amino group.

A beta sheet is an example of?

Protein secondary structure.

What affects protein 3D folding?

pH, temperature, and amino acid side chain properties.