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27 Cards in this Set
- Front
- Back
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What is a plasmid?
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A small, circular DNA molecule separate from the larger bacterial chromosome
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How is a plasmid like a chromosome
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It carries a number of genes and can make copies of itself.
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What happens when a plasmid replicates
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One copy of the genes can pass from one bacterial cell to another resulting in GENE SHARING
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What is a benefit of gene sharing
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Gene transfer by plasmids can make the bacteria stronger and more likely to survive....some bacteria have now become resistant to antibiotics
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What is gene cloning
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A plasmid is removed from a bacterial cell and the desired gene (from any cell) is inserted into the plasmid. Plasmid is now a combination of original and new DNA.
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What is recombinant DNA
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When a plasmid is now a combination of original and new DNA
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What are vectors
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Plasmids used in genetic engineering
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What does a biologist use to remove a gene from one DNA molecule and put it into another
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Restriction enzymes are used to cut out a piece of a much longer DNA molecule
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What doe the restriction enzymes do?
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In nature these enzymes protect the bacteria against intruding DNA from other oranisms and phages
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What does the restriction enzyme do
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It recognizes particular short nucleotide sequences in DNA molecules and cuts sugar-phosphate bonds in the DNA backbone at specific points within the sequence
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What kind of cut does the restriction enzyme make across the double stranded DNA?
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A staggered cut leaving single stranded DNA hanging off the end of the fragments.
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What is the single-stranded portion of the DNA called?
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The sticky end because it is available to bind to any sequence that is COMPLEMENTARY to it.
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Why are sticky ends usefl?
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Because they are used to RECOMBINE DNA.
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How do the complementary sticky ends of the two DNA fragments join together. What is the mechanism that bonds them?
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The sticky ends join by BASE-PAIRING with each other.
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What is the enzyme that PASTES the two sticky ends together?
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DNA ligase pastes the sticky ends together and thus repairs the DNA backbone.
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What does the molecular biologist need to clone a human gene?
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1. A plasmid
2. Human DNA molecule 3. A restriciton enzyme which cuts the plasmid in only one place but cuts the human DNA molecule in thousands of places |
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Which sticky ends connect up when making a Recombinant DNA plasmid?
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The sticky end of the plasmid and the sticky end of the human DNA fragment pair up according to the base pairing rules
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When the DNA ligase joins the two DNA molecules together (plasmid protein and DNA fragment), what is the joined molecule called?
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Recombinant DNA plasmid
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What is gene expression as described in the cloning of the human gene for a protein....hypotethical example was protein V.
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The bilogist puts the gene in bacterial cells that express the gene as protein thereby creating a system that can make large amounts of the protein
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What are plasmids used in genetic engineering called?
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VECTORS
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What is a genomic library
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The complete collection of cloned DNA fragments from one organism
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How does the biologist find a specific gene in the library
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One method involvesk nowing the gene's nucleotide sequence and then using nucletides labeled witha radioactive isotope to build a complementary single strand of DNA.
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What is the complementary radioactively labeled nucleic acid molecule called
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A nucleic acid probe
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What is the process for finding the desired gene
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DNA is treated with chemicals or heat to separate it into two strands and the radioactive probe pairs with the complementary sequence
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What happens once the biologist uses the radioactive probe or marker to identify the bacterial cells with the desired gene
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The identified cells are allowed to multiply further producing the gene in large amounts
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Recombinant DNA technology is used in medicine...give examples
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1. Using disabled microbes or parts of microbes to make a vaccine
2. Make human insulin |
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Does recombinant (rDNA) exist naturally.
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NO. Genetic recombination occurs naturally, but recombinant DNA is engineered.
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