Chapter 4 Review

What part of the amino acid strongly influences the way the polypeptide folds, and hence affects the three-dimensional shape of the protein? Why?

• The Amino Group

• The Carboxyl Group

• The R-Group

• The Polypeptide Bond

Can you recognize this molecule? Can you name the groups?

Answer explanation

a protein

a. amino goup

b. crboxyl group

c. alpha carbon

d. side-chain

Define primary structure:

Answer explanation

The sequence of amino acids in a protein

Define secondary structure:

Answer explanation

The structure formed by interactions between stretches of amino acids in a protein

Define tertiary structure

Answer explanation

The overall three-dimensional shape of a protein, formed by interactions between secondary structures

Define Quaternary structure:

Answer explanation

The structure that results from the interactions of several polypeptide chains

Can you identify each structure?

Answer explanation

primary

secondary

tertiary

quaternary

What structure level does this alpha helix belong in?

Answer explanation

secondary

What structure does this beta sheet belong to?

What is the difference in R-Groups between alpha and beta secondary structures?

Answer explanation

Alpha helix- R group projects outward

Beta sheet- R -groups project alternatively below