Proteins – describe their complexity based on their levels of structure

Question 1

What is the basic structure of an amino acid? How many amino acids are there? How many are essential?

Answer 1

Amino Acid Structure:
Central carbon
Hydrogen atom
Carboxyl group
Amino group
Side group (R group)

There are 20 amino acids; 11 can be synthesized by our cells, and 9 are essential and must be obtained from our diet.

Question 2

What type of reaction occurs in the synthesis of peptides? What type of bond is formed?

Answer 2

Peptide Synthesis:
Peptide bonds are formed by a dehydration synthesis reaction.
The carboxyl group of one amino acid bonds to the amino group of another.

Question 3

Define polypeptide

Answer 3

Polypeptides:
A chain of amino acids is called a peptide.
A peptide with more than 50 amino acids is called a polypeptide.

Question 4

Define protein. How is a polypeptide different from a protein?

Answer 4

Proteins:
One or more polypeptides folded into a 3D shape form a protein.
Proteins are diverse and complex, and their structure determines their function.

Question 5

Define denaturation. What factors cause a protein to denture? What are some practical examples? Is denaturation irreversible, reversible or both? Explain.

Answer 5

Proteins can lose their shape and function due to changes in pH or temperature (denaturation).
It can be caused by chemicals and heat.
It is often reversible if the primary structure is intact, but can be irreversible in extreme conditions.
Examples: Cooking eggs, digestion, and using alcohol for disinfection.

Question 6

Protein Levels

Answer 6

Primary Structure: The sequence of amino acids in a chain.

Secondary Structure: Local shapes like coils (alpha-helices) and folds (beta-pleated sheets).

Tertiary Structure: The overall 3D shape of a single protein chain.

Quaternary Structure: The arrangement of multiple protein chains into a complex.