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 2

Textbook Question

Which of the following is not true of a codon?a. It may code for the same amino acid as another codon.b. It never codes for more than one amino acid.c. It extends from one end of a tRNA molecule.d. It is the basic unit of the genetic code.

Verified step by step guidance

Identify the definition of a codon: A codon is a sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule.

Understand that each codon corresponds to a specific amino acid or a stop signal during protein synthesis.

Review the options given: a) Codons can code for the same amino acid due to the redundancy of the genetic code. b) Each codon specifies only one amino acid or a stop signal, not multiple amino acids. c) Codons are part of mRNA, not tRNA. d) Codons are indeed the basic units of the genetic code.

Analyze option c: A codon does not extend from one end of a tRNA molecule; instead, the anticodon is the part of tRNA that pairs with the codon on mRNA.

Conclude that option c is not true of a codon, as codons are associated with mRNA, not tRNA.

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Key Concepts

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

Codon Definition

A codon is a sequence of three nucleotides in mRNA that specifies a particular amino acid during protein synthesis. Each codon corresponds to one of the 20 amino acids or serves as a stop signal, making it a fundamental unit of the genetic code.

Degeneracy of the Genetic Code

The genetic code is described as degenerate because multiple codons can code for the same amino acid. This redundancy helps to minimize the impact of mutations, as a change in one nucleotide may not necessarily alter the resulting protein.

tRNA and Codon Interaction

Transfer RNA (tRNA) molecules have anticodons that are complementary to codons on mRNA. This interaction is crucial for the accurate translation of the genetic code into proteins, as each tRNA carries a specific amino acid that corresponds to its anticodon.