Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

3. Energy & Cell Processes

Genetic Code

Anatomy & Physiology

3. Energy & Cell Processes

Genetic Code

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Problem 6

Textbook Question

A minimal genetic code requires only 21 codons—one for each amino acid, and one for a stop signal. Given this, what advantage might be offered by having a code with 64 codons?

Verified step by step guidance

Understand that the genetic code is composed of codons, which are sequences of three nucleotides.

Recognize that there are 64 possible codons (4 nucleotides: A, U, G, C, each can be in one of three positions, so 4^3 = 64).

Consider that only 21 codons are needed for a minimal genetic code: 20 for amino acids and 1 for a stop signal.

Explore the concept of redundancy or degeneracy in the genetic code, where multiple codons can code for the same amino acid.

Discuss how this redundancy can provide a protective mechanism against mutations, as changes in the third nucleotide of a codon often do not change the amino acid (wobble position).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Codons and Amino Acids

Codons are sequences of three nucleotides in DNA or RNA that correspond to specific amino acids or stop signals during protein synthesis. The genetic code is composed of 64 possible codons, which allows for the encoding of 20 standard amino acids and additional signals, providing a framework for translating genetic information into functional proteins.

Redundancy in the Genetic Code

The genetic code exhibits redundancy, meaning that multiple codons can code for the same amino acid. This redundancy can provide a buffer against mutations, as changes in the DNA sequence may not always lead to changes in the protein produced, thereby enhancing the stability and adaptability of organisms.

Evolutionary Advantage of a Larger Code

Having a genetic code with 64 codons allows for greater flexibility and complexity in protein synthesis. This can lead to the evolution of new proteins with novel functions, enabling organisms to adapt to diverse environments and challenges, ultimately contributing to evolutionary success and diversity.