Chapter 20 Flashcards
DNA technology
-techniques for sequencing and manipulating DNA
DNA sequencing
-Determine complete nucleotide sequence of DNA molecule
genetic engineering
-The deliberate modification of the characteristics of an organism by manipulating its genetic material.
What is the purpose of DNA sequencing?
-diagnosis and treatment of diseases
what is a human genome project?
-goal of determining the base pairs that make up human DNA, and of identifying, mapping and sequencing all of the genes of the human genome from both a physical and a functional standpoint.
what is PCR and its purpose?
PCR = polymerase chain reaction
The purpose is it allows rapid amplification of a specific segment of DNA.
what are the three steps of PCR?
- denaturation:
-heat reaction to high temperature to separate dsDNA - annealing:
-cooling reaction allowing primers to anneal or bind to complementary sequences, primer necessary - Extension:
- extension of the new DNA strands from the primers.
why does the DNA polymerase have to be heat stable in PCR?
-high temperature is used repeatedly in PCR to denature the template DNA, or separate its strands.
what is a restriction enzyme?
-a DNA-cutting enzyme that recognizes specific sites in DNA.
where are restriction enzyme naturally found?
-bacteria (and other prokaryotes)
what is a restriction site?
-they are located on a DNA molecule containing specific sequences of nucleotides, which are recognized by restriction enzymes
what is a restriction a restriction fragment?
-DNA fragment resulting from the cutting of a DNA strand by a restriction enzyme
how could you determine if a restriction enzyme cut a DNA sample?
-by using a sequence analysis program
what is gel electrophoresis?
-a laboratory method used to separate mixtures of DNA, RNA, or proteins according to molecular size
what is the purpose of gel electrophoresis?
-visualize, identify, and distinguish molecules that have been processed by a precious method such as PCR and others
how would you expect a large versus a small DNA fragment to migrate in gel electrophoresis?
-small fragments move through the gel faster than large ones.
what is in situ hybridization?
a laboratory technique used to localize a sequence of DNA or RNA in a biological sample
what is the purpose of in situ hybridization?
-to determine the presence or absence of DNA or RNA sequences of interest, as well as to localize these sequences to specific cells or chromosomal sites
how do you design a nucleic acid primer?
- Length of 18-24 bases.
- 40-60% G/C content.
- Start and end with 1-2 G/C pairs.
- Melting temperature (Tm) of 50-60°C.
- Primer pairs should have a Tm within 5°C of each other.
- Primer pairs should not have complementary regions.
how do you interpret the results of a fluorescence micrograph?
-image specific features of small specimens such as microbes
what is somatic cell nuclear transfer?
- technique in which the nucleus of a somatic (body) cell is transferred to the cytoplasm of an enucleated egg (an egg that has had its own nucleus removed).
what is the purpose of SCNT?
-to reverse the differentiated state of a somatic cell
what is a genetic profile?
-DNA profiling is the process of determining an individual’s DNA characteristics
how is genetic profiling used?
-to connect suspects to crime scenes, to exonerate people who were wrongly convicted, and to establish or exclude paternity
what are the short tandem repeats (STRs)?
-a tract of repetitive DNA in which certain DNA motifs are repeated, typically 5–50 times.
what is a GMO?
-any organism whose genetic material has been altered using genetic engineering techniques.
what is an anode?
-the positively charged electrode by which the electrons leave an electrical device
what is a cathode?
-the negatively charged electrode by which electrons enter an electrical device.
why is primer specifically important in PCR?
-serve as the starting point for DNA synthesis
