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Ch. 5 - Genetics
Norman-McKay- Microbiology: Basic and Clinical Principles 2nd Edition
Norman-McKay2nd EditionMicrobiology: Basic and Clinical PrinciplesISBN: 9780137661619Not the one you use?Change textbook
All textbooksNorman-McKay 2nd EditionCh. 5 - GeneticsProblem 8
Chapter 5, Problem 8

Label the following as a biological, chemical, or physical mutagen:
UV radiation:
Transposons:
Cigarette smoke:
Viruses:
X-rays:
Plasmids:
Alcohol:

Verified step by step guidance
1
Understand the definitions of the three types of mutagens: Biological mutagens are living organisms or their products that cause mutations (e.g., viruses, transposons, plasmids). Chemical mutagens are substances that chemically alter DNA, leading to mutations (e.g., cigarette smoke, alcohol). Physical mutagens are physical agents that cause DNA damage through energy exposure (e.g., UV radiation, X-rays).
Analyze each item in the list and classify it based on the definitions: UV radiation is a form of electromagnetic radiation that causes DNA damage by inducing thymine dimers, so it is a physical mutagen.
Transposons are DNA sequences that can move within the genome, causing mutations by insertion or excision, and are considered biological mutagens because they are genetic elements within organisms.
Cigarette smoke contains many chemical compounds that can interact with DNA and cause mutations, so it is classified as a chemical mutagen.
Viruses can insert their genetic material into host DNA, disrupting normal function and causing mutations, making them biological mutagens.
X-rays are high-energy radiation that can break DNA strands, so they are physical mutagens.
Plasmids are small, circular DNA molecules in bacteria that can carry genes and sometimes cause mutations when transferred, so they are biological mutagens.
Alcohol can cause mutations indirectly by generating reactive oxygen species and interfering with DNA repair, classifying it as a chemical mutagen.

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Key Concepts

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

Types of Mutagens

Mutagens are agents that cause changes or mutations in the DNA sequence. They are classified into biological (living organisms or their products), chemical (substances that interact chemically with DNA), and physical mutagens (forms of radiation or physical energy). Understanding these categories helps in identifying the nature of different mutagenic agents.
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Radiation Mutagens

Physical Mutagens

Physical mutagens include forms of radiation such as UV light and X-rays that cause DNA damage by inducing breaks or chemical changes in the DNA structure. These mutagens alter the DNA through energy transfer, leading to mutations like thymine dimers or strand breaks.
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Biological and Chemical Mutagens

Biological mutagens include entities like viruses, transposons, and plasmids that can insert or alter genetic material within a host. Chemical mutagens, such as cigarette smoke and alcohol, contain compounds that chemically modify DNA bases or cause replication errors, leading to mutations.
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Related Practice
Textbook Question

Codons are ___________ nucleotides long and are in ___________, which is transcribed from DNA. During ___________, tRNAs serve as adapter molecules to bring ___________ to the ribosome to build a protein. Once the ribosome reaches a(n) ___________ on the mRNA, translation ends.

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Textbook Question

How is a ribonucleotide different from a deoxyribonucleotide?

Textbook Question

For the lactose operon to be “on” and actively transcribed, ___________ must be present and ___________ must be absent.

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Textbook Question

Assume you have the DNA sequence 3'-ACGTATCCAGCAGCTCCACCAA-5'.

Use the genetic code table found in the chapter to answer the following questions:

a. What would the complementary DNA sequence be?

b. What would the corresponding mRNA sequence be?

c. Could the mRNA sequence you generated be translated? Why or why not?

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Textbook Question

During ___________ a pilus forms between an F+ and an F−cell and allows for the exchange of genetic material. By the end of the process, the previously F− cell is converted to a(n) ___________ cell.

Textbook Question

Why are the terms gene expression and protein synthesis often used interchangeably?

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