Table of contents

Skip topic navigation

1. Introduction to Biochemistry4h 34m
2. Water3h 23m
3. Amino Acids8h 10m
4. Protein Structure10h 4m
5. Protein Techniques14h 5m
6. Enzymes and Enzyme Kinetics13h 38m
7. Enzyme Inhibition and Regulation 8h 42m
8. Protein Function 9h 41m
9. Carbohydrates7h 49m
10. Lipids5h 49m
11. Biological Membranes and Transport 6h 37m
12. Biosignaling9h 45m
Review 1: Nucleic Acids, Lipids, & Membranes2h 47m
Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway3h 12m
Review 3: Pyruvate & Fatty Acid Oxidation, Citric Acid Cycle, & Glycogen Metabolism2h 26m
Review 4: Amino Acid Oxidation, Oxidative Phosphorylation, & Photophosphorylation1h 48m

4. Protein Structure

Protein Motifs and Domains

Biochemistry

4. Protein Structure

Protein Motifs and Domains

Previous problemNext problem

Struggling with Biochemistry?

Join thousands of students who trust us to help them ace their exams!Watch the first video

Multiple Choice

The structure of an immunoglobulin G (antibody) molecule is shown schematically below. The black solid lines depict individual polypeptides and so there are four polypeptides in the quaternary structure of this molecule. Each of the spheres represents a stretch of about 100 amino acids folded independently of the rest of the polypeptide and performs a specific function in the molecule. Therefore, each sphere was given its own individual name (VH, CH1, CH2, etc.). Without knowing any additional details, you can predict that there must be TWELVE ___________________ in this molecule.

α-helices.

Domains.

Subunits.

Motifs.

Previous problemNext problem

Verified step by step guidance

Begin by examining the schematic representation of the immunoglobulin G (IgG) molecule. Notice that it consists of four polypeptide chains, depicted by the black solid lines.

Identify the spheres labeled VH, CH1, CH2, CH3, VL, and CL. Each sphere represents a domain, which is a distinct structural and functional unit within the polypeptide chain.

Count the number of spheres in the diagram. There are twelve spheres in total, indicating twelve domains within the IgG molecule.

Understand that each domain is approximately 100 amino acids long and folds independently, contributing to the specific function of the antibody.

Conclude that the correct term to fill in the blank is 'Domains,' as each sphere represents a domain in the quaternary structure of the immunoglobulin G molecule.