With reference to Induction of Mutation, classify mutagens giving examples of each. (15 Marks) QUESTION 10 Discuss characteristics of the Genetic code. (15 Marks)

**Induction of Mutation: Classification of Mutagens**<br /><br />Mutagens are agents that induce mutations in the DNA sequence. They can be classified into several categories based on their nature and mechanism of action:<br /><br />1. **Chemical Mutagens:**<br /> - **Alkylating Agents:** These chemicals add alkyl groups to DNA bases, causing mispairing during DNA replication. Example: Ethyl methanesulfonate (EMS).<br /> - **Base Analog Mutagens:** These compounds mimic DNA bases and get incorporated into DNA during replication, leading to incorrect base pairing. Example: 5-Bromouracil.<br /><br />2. **Radiation Mutagens:**<br /> - **Ionizing Radiation:** This type of radiation, such as X-rays and gamma rays, causes breaks in DNA strands, leading to mutations. Example: X-ray radiation.<br /> - **Non-Ionizing Radiation:** UV radiation from the sun causes thymine dimers, leading to mutations during DNA replication. Example: UV radiation.<br /><br />3. **Biological Mutagens:**<br /> - **Viruses:** Certain viruses can integrate their genetic material into the host genome, causing mutations. Example: Adenoviruses.<br /><br />4. **Physical Mutagens:**<br /> - **Chemical Mutagens:** Some chemicals, like certain pesticides, can induce mutations. Example: Atrazine.<br /><br />**Characteristics of the Genetic Code**<br /><br />The genetic code is a set of rules that living cells use to translate information encoded within genetic material (DNA or mRNA sequences) into proteins. It is the language of life, and its characteristics are fundamental to understanding how genetic information is expressed. Here are some key characteristics:<br /><br />1. **Degeneracy:**<br /> - The genetic code is degenerate, meaning that multiple codons (three-nucleotide sequences) can code for the same amino acid. This provides a buffer against mutations.<br /><br />2. **Redundancy:**<br /> - The genetic code is redundant, meaning that a single amino acid can be coded for by multiple codons. This is not to be confused with degeneracy.<br /><br />3. **Universality:**<br /> - The genetic code is nearly universal, with only minor variations among different organisms. This universality suggests a common origin for all life.<br /><br />4. **Start and Stop Codons:**<br /> - The genetic code includes specific codons that signal the start (AUG) and stop (UAA, UAG, UGA) of protein synthesis.<br /><br />5. **Reading Frame:**<br /> - The genetic code is read in sets of three nucleotides, known as codons, which correspond to specific amino acids or stop signals during protein synthesis.<br /><br />6. **Wobble Position:**<br /> - The third nucleotide in a codon (the wobble position) is more flexible in its base pairing, allowing for some degeneracy in the code.<br /><br />7. **Codon-Amino Acid Correspondence:**<br /> - Each codon corresponds to a specific amino acid or a stop signal. This correspondence is what gets translated into proteins during gene expression.<br /><br />Understanding these characteristics of the genetic code is crucial for fields such as molecular biology, genetics, and biotechnology, as it provides insights into how genetic information is translated into functional proteins.