Protein Functions, Amino Acid Chains, and Structural Organization

All flashcards

What is an enzyme?

An enzyme is a biological catalyst, usually a protein, that increases the rate of a biochemical reaction by acting on a particular substrate.

What are the four groups attached to a typical amino acid's alpha carbon?

An amino group, a carboxyl group, a hydrogen atom, and a variable R group or side chain.

What does an amino acid's R group determine?

The R group differs among amino acids and helps determine whether an amino acid is, for example, polar, nonpolar, acidic, or basic.

What are essential amino acids?

They are amino acids that a human body cannot make in sufficient amounts and therefore must obtain from the diet.

Give three functions proteins can perform.

Proteins can catalyze reactions, transport substances, provide structure, signal between cells, defend against pathogens, store nutrients, or enable contraction.

Quiz questions

1. How does a peptide bond form between two amino acids?Answer: A covalent bond forms between their amino and carboxyl groups, releasing water.
2. What does the primary structure of a protein describe?Answer: The amino acid sequence of the protein
3. What can fewer differences in a protein sequence between two species indicate?Answer: The species may be more closely evolutionarily related.
4. When a protein is denatured, what usually remains intact?Answer: Its primary amino acid sequence
5. What is one role of chaperone proteins during folding?Answer: They help prevent unfolded polypeptides from aggregating improperly.