The number of genes in an organism's genome is not a perfect indication of the organism's complexity because __________.

• A. alternative splicing can increase the number of polypeptides made from a single pre-mRNA
• B. post-translational modifications can increase the types of proteins produced by a single gene
• C. individual polypeptides can interact to form multiple types of protein complexes
• D. individual genes can be expressed in more or less complex ways in different organisms
• E. All of the listed responses are correct.

Answer: (E)

Verified step by step guidance

1. Understand that the number of genes in an organism's genome does not directly correlate with its complexity. This is because complexity can arise from various processes that increase the diversity of proteins and their functions.
2. Consider alternative splicing: This process allows a single pre-mRNA transcript to be spliced in different ways, resulting in multiple polypeptides from one gene. This increases the diversity of proteins without increasing the number of genes.
3. Examine post-translational modifications: After a protein is synthesized, it can undergo various chemical modifications that alter its function and activity. This means a single gene can give rise to multiple protein forms with different functions.
4. Explore protein complex formation: Individual polypeptides can interact with each other to form complex protein structures. These interactions can lead to a variety of functional protein complexes, adding to the organism's complexity.
5. Recognize gene expression variability: The same gene can be expressed differently in various organisms or even in different tissues within the same organism. This variability in expression can lead to differences in complexity and function.