CPA #13 Questions Flashcards
define: recombinant DNA technology
aka genetic engineering; intentionally modifying the genomes of an organism
what are the 3 main goals of recombinant DNA technology
- eliminate undesirable phenotypic traits
- combine beneficial traits of 2 or more organisms to create valuable new organism
- create organisms that synthesize products that humans need
define: reverse transcriptase
creates flow of genetic info in reverse order of conventional transcription; RNA template used to transcribe a molecule of DNA (cDNA); violating the central dogma
ex. viruses
define: cDNA
DNA that is complementary to an RNA template
explain synthetic nucleotides
molecules of DNA/RNA in a cell-free solution
- elucidating the genetic code;
- creating genes for specific proteins
- synthesizing DNA/RNA probes to locate specific sequences of nucleotides
- synthesizing antisense nucleic acid molecules
- synthesizing PCR primers
5 ways synthetic nucleic acids are used
nucleic acid molecules with a specific nucleotide sequence that have been labeled radioactive/florescent chemicals so that their location can be detected; a given nucleotide sequence will preferentially bond to the complementary sequence
probes
enzymes that cut DNA molecules at the restriction site; usually used as a bacterial protection mechanism to protect from phages by cutting phage DNA into nonfunctional pieces
restriction enzymes
define: restriction site
specific nucleotide sequence; usually palindromes (same sequence forwards and backwards)
define: blunt ends
both DNA strands are cut at the same point; non-specific because all of the hydrogen bonds are satisfied
define: sticky ends
both strands of DNA are cut by staggered cuts that produce fragments that terminate in a mortise-like end; composed of 4 nucleotides that form hydrogen bonds with the complementary sticky end; specific, unsatisfied hydrogen bonds
define: vector
nucleic acid molecules such as viral genomes, transposons, and plasmids that deliver a gene into a cell
define: gene library
collection of bacterial or phage clones that are identical descendants; each one contains portion of genetic material
why do we use gene libraries?
more time efficient because you do not have to isolate the genes every time, they are already readily available; use restriction enzymes to generate fragments of the DNA and then use ligase to synthesize recombinant vectors
what are the 6 purposes of recombinant DNA?
- multiply
- identify
- manipulate
- isolate
- map
- sequence
define: PCR
polymerase chain reaction; produce large number of identical molecules of a specific segment of DNA in vitro
what are the ingredients of PCR?
excess DNA primers, Taq DNA polymerase, abundance of the 4 deoxyribonucleic acids (A,T,G,C)
what are the three steps of PCR?
- denaturation
- priming
- extension
define: denaturation (PCR)
exposure to heat (94C) to separate two strands of the target DNA ; breaks hydrogen bonds, but leaves strands unaltered
define: priming (PCR)
PCR mixture is added to target DNA; cool to 65C
define: extension (PCR)
raise temp to 72C to increase the rate that DNA polymerase replicates each strand for more DNA
define: gel electrophoresis
isolate fragments of DNA molecules that can be inserted into vectors, multiplied by PCR, or preserved in gene libraries
what three characteristics are used to separate molecules of gel electrophoresis?
- size
- charge
- shape
define: southern blot
presence of DNA
define: northern blot
presence of RNA
what is the purpose of DNA microarray?
monitor gene expression, diagnose infection, identify organisms in an environmental sample
what are the 3 artificial methods to introduce DNA to cells?
electroportation, protoplast fusion, injection
define: electroporation
uses electrical current to puncture microscopic holes through cell membrane so that DNA can enter
define: protoplast fusion
when protoplasts encounter one another, the cytoplasmic membranes may fuse to form a single cell containing 2 genomes; polyethylene glycol increases rate of fusion
define: injection
- gene gun
- microinjection
used with larger eukaryotic cells
define: genetic mapping
locating genes on nucleic acid molecule; provides scientists with information like: organisms metabolism and growth characteristics and potential relatedness to other microbes
define: genomics
sequencing and analysis of the nucleotide bases of genomes of organisms, viruses, and eukaryotic mitochondria
how can scientists use recombinant DNA for pharmaceutical/therapeutic applications?
- synthesize medically impportant proteins
- produce vaccines
- screen for genetic diseases
- diagnose diseases
- aid in organ transplant
- treat genetic illnesses
- make animals respond more similarly to humans when treated with pathogens
how can scientists use recombinant DNA for agricultural application?
- herbicide resistance
- tolerance to salty soil
- resistance to freezing and pests
- improvement in nutritional value
