Chapter 20 Flashcards
biotechnology
the manipulation of organisms or their components to make useful products
nucleic acid hybridization
the base pairing of one strand of a nucleic acid to complementary sequence on strand from another nucleic acid molecule
o The key to DNA sequencing
genetic engineering
direct manipulation of genes for practical purposes
DNA sequencing
determining the complete nucleotide sequence of a DNA molecule
Deoxyribonucleotide chain termination sequencing (DNA sequencing)
technique in which one strand of DNA fragment is used as a template for synthesis
o Strands are differentiated by length
Sequencing by synthesis (DNA sequencing)
technique in which electronic monitors identify which of four nucleotides is added
third generation sequencing
involves moving a single strand of DNA molecule through a small pore in a membrane and detecting the bases using an electrical current (measure different lengths of time in which base interrupts current)
DNA cloning
preparing well-defined segments of DNA in multiple identical copies
plasmids
small, circular DNA molecules that are replicated separately
o Found only in bacteria
recombinant DNA
a molecule containing DNA from 2 different sources
o Taking one strand of DNA and combining it with another strand of DNA
Gene cloning
the production of multiple copies of a single gene
cloning vector
DNA molecule that carries foreign DNA into a host cell and replicates there, producing many copies of itself and the foreign DNA
restriction enzymes
enzymes that cut DNA molecules at a limited number of specific locations
restriction site
a particular short DNA sequence which is recognized by restriction enzymes
restriction fragments
sequences containing 4-8 nucleotide pairs
o Result from cutting DNA strand by restriction enzyme
sticky-end
double-stranded restriction fragments which have at least 1 single-stranded end
o They result when useful restriction enzymes cleave the sugar phosphate backbones
o Can form H bond base pairs with complementary sticky ends on DNA molecules cut with the same enzyme
DNA ligase
catalyzes the formation of covalent bonds that close up sugar-phosphate backbones of DNA strands
o Glues together the H bonding of the sticky end to other DNA molecules
Gel electrophoresis
uses gel to separate mixture of nucleic acids on the basis of size, electrical charge, and other physical properties
Polymerase chain reaction
start with genomic DNA to get several copies of desired gene
(Don’t worry about stuff below.)
o Denaturation: Heat to separate
o Annealing: Cool to recombine and form H bonds b/t primers and ends of target sequence.
o Extension: DNA polymerase adds nucleotides to 3’ end of each primer (5’→3’ direction)
o Taq polymerase: DNA polymerase that can withstand heat
o Primer sequences are chosen only so they hybridize only to sequences at opposite ends of target segment (3’ end of each strand)
o Number of molecules= 2^n where n is the number of cycles
Extension (PCR)
DNA polymerase adds nucleotides to 3’ end of each primer (5’→3’ direction)
Taq polymerase (PCR)
DNA polymerase that can withstand heat
expression vector
a cloning vector that contains an active bacterial promoter upstream of a restriction site where eukaryotic gene can be inserted into the correct reading frame
electrocorporation
a brief electrical pulse applied to a solution containing cells which creates temporary holes in plasma membranes through which DNA can enter
nucleic acid probe
short, single-stranded complementary nucleotide used to do nucleic acid hybridization with mRNA
o Can be DNA or RNA
(nucleic acid complementary to another nucleic acid)
