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Distinguish among recombinant DNA, genetically modified organisms, and transgenic organisms.
- -DNA Tech: manipulation of
- genetic material, even moving genes from one organism to another
- -Recombinant DNA: a DNA
- molecules that derives from two or more sources
- -Genetically modified organism:
- organism with one or more genes introduced using DNA technology
- -Transgenic organism: A GMO
- which has genes from more than one organism
What is a restriction enzyme? Make sure you understand restriction maps and ‘sticky ends’.
Reaction enzyme: proteins that cleave DNA at restriction sites Sticky Ends: any DNA cut by a particular restriction enzyme can stick to any other cut by the same enzyme
What is a plasmid, where can they come from, and what organisms have them?
A genetic structure in a cell that can replicate independently of the chromosome, typically a small circular DNA strand in the CYTOPLASM of a bacterium
Describe the process of creating a recombinant DNA molecule.
- smaller pieces of DNA to wok with restriction enzymes
- fragments: gel electrophoresis
- a particular sequence in the genome: nucleic acid probes
- many copies of the DNA: cloning by biological vector or polymerase chain
What is gel electrophoresis, what is its purpose, and how does it work?
Separating molecules by size, charge etc -measures movement based on a standard -placed in gel and move by electrical charge
What are the two ways to clone a gene?
- such as bacteria, yeast, cell culture
- -gene cleaved out of original genome using a particular
- restriction enzyme
- -gene inserted into bacteria plasmid (vector) cut with the
- same enzyme to transfer (recombinant DNA) by shaking them together
- Polymerase chain reactions (PCR)
- -clones of DNA sequence
- without a biological vector
Describe how a gene can be cloned in a
- engineering plasmid and DNA of interest cut with same restriction enzyme and
- mixed together, some combine
- is exposed to a biological vector such as yeast or bacteria. Some vectors pick up DNA
- vectors are screened to identify those which picked up a plasmid which
- contained the DNA of interest
- selected vectors are allowed to reproduce making more copies of the DNA of
Describe how the polymerase
chain reaction (PCR) can be used to amplify genes.
PCR produces copies from one sample
- sequence of dna to be amplified)
- pol (heat-stable version-TAQ Polymerase)
- to 95 C, so dna denatures to single strands
- primers attach to their complimentary sequence
- pol adds nucleotides to finish complimentary strand
- rounds yield more copies
What is a nucleic acid probe used to accomplish?
Nucleic acid probe: finding the correct gene
- stranded sequence of interest is labeled (dye, radiation)
- mixed with the sample, it sticks to its compliment
- single stranded sequence
- CCGGTTAA PROBE à DNA sequence labeled
Understand how forensic tests and
paternity analyses are based on, and how the chance of mistaken identity error
can be reduced.
- -based on
- highly variable non-coding sequences
- -cut with
- restriction enzymes
- radioactive probes used to determine which fragments are present
- -based on
- single tandem repeats (STR’s) non-coding DNA more variable than coding DNA
What is a genome?
- The study of
- entire genomes
- About 4000
- species sequenced (mostly prokaryotes)
How is information in the genome
apportioned between coding and non-coding DNA?
What are the types of coding and
- -24% introns
- and regulatory sequence
- -15% structural
- DNA around centromeres or ends (telomoeres); mostly simple sequence repeats
- transposable elements (jumping genes)
What is the biggest reason that
mammalian cloning is difficult?
- Humans are
- more complex with approx. 100,000 genes
What is methylation, and what does it do
- Passing of a
- chemical fragment called methyl group from one molecule to another.
Potential exam question: Why is a random mutation
unlikely to affect a protein? Include the approximate percentages for the
categories of DNA discussed in class in your answer.