Questions and Answers
DNA segments that can move within the genome are known as ______.
transposons
The process by which bacteriophages may integrate into a bacterial host's chromosome is known as ______ conversion.
lysogenic
Mutations can occur due to exposure to certain chemical and physical ______.
agents
A change in the DNA base sequence is referred to as a ______.
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Bacteriophages that do not immediately kill their host are often involved in ______ cycles.
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The bacterial DNA carried by a bacteriophage enhances its ability to ______ genetic material.
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The term ______ is used to describe the phenomenon where cells can become immune to reinfection by the same phage.
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Mutations can result from errors during ______ replication.
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The donor strain (F+) possesses a fertility factor (F factor) on a ______ that carries the genes for conjugative transfer.
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Bacteriophage are ______ that consist of a chromosome surrounded by a protein coat.
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The ______ or virulent phage replicates usually through the lytic cycle.
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The production of viruses using a host cell to manufacture more viruses would cause the ______ bacteria to die.
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Bacteriophage DNA directs the bacterial cell to synthesize phage ______ and phage protein.
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In the lytic phase, the bacterial cell eventually ______, releasing a new phage.
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Temperate phage can replicate through the ______ cycle.
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The incorporation of the viral genome into the host cell genome creates a ______.
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The donor strain produces a hollow surface appendage called a ______ or conjugation pilus.
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Resistance plasmid conjugation involves sharing of the ______ which provides some form of antibiotic resistance.
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Transformation occurs after the uptake of DNA fragments from the ______
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The chromosome is a single, long piece of circular, double-stranded ______
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Bacterial DNA contains 2000 to 4000 ______
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Plasmids replicate ______
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The RecA protein is a recombinase functioning in a recombinational DNA ______ in bacteria
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Vertical gene transfer occurs from mother to cell ______
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Horizontal gene transfer includes processes such as ______ and transduction
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Plasmids can contain genes for toxins and proteins that promote ______
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Competent bacteria are able to accept naked DNA from the ______
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The number of plasmids in a bacterial cell may range from one to ______
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Study Notes
Bacterial Genetics Overview
- Bacterial transformation involves the uptake of DNA fragments from the environment.
- The bacterial chromosome consists of a single, circular, double-stranded DNA with 2000 to 4000 genes essential for growth and replication.
Plasmids
- Plasmids are small, circular DNA that replicate independently and contain genes for toxins and proteins promoting gene transfer.
- They are not essential for growth, allowing bacteria to gain or lose them.
- Plasmids can range from one to hundreds in a bacterial cell and may be exchanged nonsexually between species.
Gene Transfer Mechanisms
- Vertical Gene Transfer occurs through binary fission from mother to offspring.
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Horizontal Gene Transfer includes:
- Conjugation: DNA transfer from a donor (F+) strain to a recipient via a sex pilus. The donor carries the F factor on a plasmid.
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Transduction: Involves bacteriophages transferring DNA fragments between bacteria, with phages having either a lytic or lysogenic cycle.
- Lytic Cycle: Destroys host bacteria, producing new phage particles that infect other bacteria.
- Lysogenic Cycle: Integrates viral DNA into the host genome, creating a prophage without immediately killing the host.
Bacteriophage Types
- Lytic or Virulent Phage: Causes host bacterial cell lysis, generating new viruses.
- Temperate Phage: Integrates into the host genome and can remain dormant as a prophage.
Transposons
- Transposons are mobile DNA segments capable of integrating into chromosomal DNA and facilitating the spread of antibiotic resistance genes.
Mutation
- Mutations are changes in the DNA sequence that may alter protein coding, arising from single nucleotide changes or errors during replication at a rate of 1 in 10 million cells.
- Physical and chemical agents can significantly elevate mutation rates.
Mobile Genetic Elements
- Mobile genetic elements, also known as "jumping genes," can relocate within the chromosome, influencing genetic variability and evolution.
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Description
This quiz focuses on the principles of clinical bacteriology with a specific emphasis on bacterial genetics, particularly the process of transformation. Ideal for 1st semester students preparing for prelims, it covers key concepts related to DNA uptake and chromosome structure in bacteria.
