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z-MicroBio Final - Ch. 7,9,10
Dr. White UCF
22
Microbiology
Undergraduate 3
04/30/2009

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Term
Central Dogma of MicroBio
Definition
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Term
GENE
Definition
the nucleotide sequence coding for a single polypeptide chain, or a ribosomal RNA, or a t-RNA.

anti-sense strand of DNA is transcribed into a mRNA
Term
Prokaryote vs Eukaryotes (RNA)
Definition
Prokaryote. A single mRNA often contains more than one coding region (such mRNAs are called polycistronic). In Eukaryotes, the DNA contains introns and exons. The Primary RNA transcript must undergo processing which means the introns must be removed and the exons are spliced back together to make mature mRNA that is transported to the cytoplasm. The mRNAs of eu are almost always monocistronic (only code for one polypeptide chain).
Term
Structure of DNA
Definition
Polymer of deoxyribonucleotides held together by 3’5’ phosho-diester bonds.
DNA is double stranded & anit-parallel with the two strands held together by hydrogen bonding between the bases.
The hydrogen bonds between the bases will break as temperature is raised, but not the covalent bonds.
This will separate the strands and DNA is said to melt.
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Term
DNA in eukaryotes
Definition
associates with basic proteins called histones to form nucleosome
Term
DNA in Prokaryotes
Definition
the DNA is also double stranded but the ends are closed to make a circle. In both cases the DNA is highly coiled.
Term
Nonchromosomal genetic elements include
Definition
Viruses – either DNA or RNA viroids: small pieces of RNA Plasmids – small genetic elements that exist and replicate separately from the major bacterial “chromosome”. Most are circular polynucleotides that do not usually cause cell damage and they do not have extra cellular forms. (Some can integrate into host DNA.)
Term
Circular DNA Reproduction
Definition
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Term
tRNA Production
Definition
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Term
Mutations
Definition
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Term
Comparison of naked and enveloped virus
Definition
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Term
Plaque Count Assay
Definition
Top agar contains phage dilution and is seeded with bacterial host cells. Where a single virion is present it replicates and lysis the host cells in the vicinity and forms a plaque.
Term
Animal viruses
Definition
penetration involves the entrance of both the protein coat & the nucleic acid, but then an uncoating enzyme removes the protein coat.
Term
Hershey-Chase
Definition
experiment with bacteriophage supported DNA as genetic material. They labeled DNA with P32 and the protein with S35 and observed that the phosphorous label went into the host cell. Most of the sulfur stayed on the outside. But if they had used an animal virus, they would have both labels go in.
Term
Lytic Cycle
Definition
Lytic or virulent cycle – virus replication occurs and the host is lysed
Term
Lysogenic cycle
Definition
Lysogenic cycle – the viral nucleic acid integrates into the host chromosome and replicates when the host DNA replicates

In the integrated state it is called a prophage, which can be induced and when it is it undergoes a lytic cycle and produces mature viruses that lyse the cell.
Term
Lysogenic versus Lytic
Definition
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Term
Possible effects that an animal virus may have on the cell it infects
Definition
1. Latent infection
virus present but not causing harm to cell, but later emerges in virulent
(lytic) infection.

2. Persistent infection
slow release of virus without cell death.
3. Virulent (lytic)
death of cell and release of virions.

4. Transformation into Tumor cells
Transformation into tumor cell and replication to form more tumor cells.
In transformation, the virus infects the animal cell and is then integrated into host DNA where it is later transcribed into tumor virus mRNA to produce proteins that alter the cell to tumor state.

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Term
Replication of Retrovirus
Definition
It is a single strand RNA virus that penetrates into animal cell and is uncoated. It has a reverse transcriptase enzyme that converts single strand RNA into a complementary DNA that is converted to double strand DNA. The double strand DNA is integrated into host DNA. When it is transcribed, it produces viral single strand RNA and protein coat subunits that are assembled into the virion which is released by a budding process that places host membrane
Term
Transformation
Definition
genetic transfer mediated by small pieces of double stranded extracellular DNA
Term
Transduction
Definition
genetic transfer mediated by virus.
Term
Conjugation
Definition
DNA transfer from donar to recipient cell mediated by cell to cell contact and sometimes bridge formation.
(3 – plasmid 4 chromosome)
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