5) Tertiary Structure

Question 1

Describe the TERTIARY STRUCTURE.

Answer 1

The overall three-dimensional structure of a polypeptide is called its tertiary structure. The tertiary structure is primarily due to interactions between the R groups of the amino acids that make up the protein.

Question 2

Name the three types of bonds that can form between the R groups.

Answer 2

1. Hydrogen
2. Ionic
3. Disulphide Links (Bridges)

Question 3

Hydrogen bonds form between ..?

Answer 3

Polar R Groups

Some R Groups are comprised of Oxygen (O) molecules and Hydrogen (H) molecules. They are polar groups as the Oxygen molecules have a slightly negative charge, and Hydrogen molecules have a slightly positive charge.

As long as the R group is polar, hydrogen bonds can form!

Question 4

Ionic Bonds form between ..?

Answer 4

Any POSITIVE and NEGATIVELY charged R Groups

Remember, opposite charges attract one another.

Question 5

Disulphide Links form between ..?

Answer 5

Any R Groups that have SULPHER atoms in them.

Question 6

The specific 3D structure is also determined by …?

Answer 6

HYDROPHILIC and HYDROPHOBIC R Groups

Amino acids with hydrophobic R Groups tend to be found in the centre of the protein.
Amino acids with hydrophilic R Groups tend to be found on the outside of the protein.
This drive of the hydrophilic and Hydrophobic R Groups also helps to fold up the shape.

Question 7

The Primary Structure determines ..?

Answer 7

The Tertiary Structure

The sequence of amino acids in a protein (the primary structure) will determine where alpha helices and beta sheets (the secondary structures) will occur. These secondary structure motifs then fold into an overall arrangement that is the final 3-dimensional fold of the protein (the tertiary structure).