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16 Cards in this Set
- Front
- Back
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1. What is a plasmid?
2. Where are they? 3. How do they replicate? 4. How big are they? 5. What is the most common conformation? |
1. A molecule of DNA distinct from chromosomal DNA
2. Found in many Prokaryotic cells 3. Replicate Autonomously 4. 1.5kb to over 300kb 5. Supercoiled CCC (Covalently Closed Circular dsDNA) |
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What is the function of a Plasmid?
(6..... 2 in CAPS) |
Encode products which modify phenotype:
ANTIBIOTIC RESISTANCE Heavy Metal Resistance Synthesis of BACTERIOCINS Restriction Endonucleases Toxins Virulence Factors |
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What is F Factor?
...and why is it important? |
Fertility Factor / Sex Factor / F-plasmid
A Bacterial DNA sequence which allows the productions of a SEX PILUS needed for CONJUGATION. |
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What is Conjugation?
How do conjugative plasmids transfer their genes? What else can the conjugative plasmid do? |
Plasmid promotion of their own intracellular transfer.
Transfer Genes are in an Operon Can mobilize the Host cell chromosome (or other non-conjugative plasmids) for Intercellular Transfer |
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What is a virus with a bacterial host?
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Bacteriophage (or just Phage)
A given phage can infect one (or just a few) strains or species of bacteria |
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What are the possible structures of phage?
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Simple (icosahedral, filamentous, or pleomorphic)
Complex (polyhedral head, or Capsid, linked to a tail structure) |
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1. Do phage have DNA or RNA?
2. What is special about phage genome? 3. How many genes are in phage genome? |
1. Either one --- but not both!
2. Many bases are modified, this protects it against nucleases 3. From 3 genes to over 100! |
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Define Virion
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A complete virus particle with its DNA/RNA core and Protein Coat as it exists outside the cell. Also called a viral particle.
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Stages of Phage Replication
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1. Adsorption (Attachment)
2. Penetration 3. Eclipse (Host cell DNA is degraded) 4. Replication (new virus particles) 5. Release from the cell |
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Some virulent phages always induce a _________ in the host cell while other temperate phage can establish a _________ relationship which is called _________
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Lytic Cycle
Non-Lytic Lysogeny |
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Process of phage moving from Temperate to Virulent?
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SOS Response
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Best Assay for Lytic Phage?
What is a pfu? |
PLAQUE Assay - drop phage onto plate lawned with bacteria
A plaque is a clear area which results from lysis of bacteria. Each plaque arises from a single infectious phage. pfu = Infectious particle that forms a plaque (Plaque Forming Unit) |
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What is Lysogeny?
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Genome of temperate phage establishes a stable, non-lytic relationship in its living host w/o producing progeny virions.
PROPHAGE incorporated into host DNA and is replicated BY THE HOST. The host cell is "Lysogenic" |
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What are jumping gense?
Are they found in Prokaryotes or Eukaryotes? |
1. Transposons! or TE's (Transposable Elements)
Discrete DNA segments which translocate to another site in the same REPLICON 2. Found in Pro and Eu -karyotes. Exist in NORMAL genomes. |
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What is an Insertion Sequence? (IS)
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A short DNA sequence that acts a a simple TE. IS are much smaller than TE, and only encode proteins implicated in TRANSPOSITION Activity (eg Transposase).
Protein coding region is flanked by a Direct Repeat and an Inverted repeat. |
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What is a Composite Transposon?
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A TE composed of structural genes which is flanked on either side by an IS
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