Match the level of protein structure with its description Question 26 options: Results when two or more polypeptide chains form one macromolecule Unique sequence of amino acids of each protein. Results from hydrogen bonding between carbonyl and amino groups in the peptide backbone. Results from interactions between R-groups 1. Primary 2. Secondary 3. Tertiary 4. Quaternary
The Correct Answer and Explanation is:
Correct Matching:
- Results when two or more polypeptide chains form one macromolecule — 4. Quaternary
- Unique sequence of amino acids of each protein — 1. Primary
- Results from hydrogen bonding between carbonyl and amino groups in the peptide backbone — 2. Secondary
- Results from interactions between R-groups — 3. Tertiary
Explanation
Proteins are complex biological molecules that function in nearly every process within living organisms. Their function is determined by their structure, which is organized into four distinct levels: primary, secondary, tertiary, and quaternary.
The primary structure is the unique sequence of amino acids in a polypeptide chain. These amino acids are linked by peptide bonds. This linear arrangement is determined by the genetic code and forms the foundation for all higher levels of protein structure.
The secondary structure arises from hydrogen bonding between the carbonyl oxygen and the amide hydrogen in the backbone of the polypeptide chain. This interaction creates regular patterns such as alpha helices and beta-pleated sheets. These structures provide the protein with some initial stability and shape.
The tertiary structure involves the overall three-dimensional folding of a single polypeptide chain. This level is stabilized by interactions between the R-groups (side chains) of the amino acids. These interactions include hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bridges. The tertiary structure is crucial for the protein’s biological activity.
The quaternary structure is formed when two or more polypeptide chains (also called subunits) come together to form a functional protein complex. Hemoglobin is a good example, composed of four polypeptide subunits working together to carry oxygen.
Each level of protein structure is essential and contributes to the final shape and function of the protein. Changes or errors at any level, especially in the primary sequence, can affect folding and lead to loss of function or disease, such as in sickle cell anemia. Understanding these levels helps explain how proteins are built and how they perform their specific roles in the cell.
