key words Flashcards
(48 cards)
base sequencing
the procedure of determining the order of nucleotides in a DNA section
DNA gyrase
a bacterial enzyme that catalyses the breaking and re-joining of bonds linking adjacent nucleotides in circular DNA to generate supercoiled DNA helices
DNA polymerases
various enzymes that function in the replication and repair of DNA by catalysing the linking of nucleotides in a specific order, using single-stranded DNA as a template
DNA primase
an enzyme involved in the initiation of DNA replication that catalyses the polymerisation of short RNA primers on the template DNA
DNA profiling (genetic fingerprinting)
the analysis of a small amount of genetic material used to identify multilocus DNA banding patterns that are specific to an individual is often used to provide evidence in criminal law cases
DNA replication
the process of making an identical copy of a DNA molecule, using existing DNA as a template for the synthesis of new DNA strands
helicase
a prokaryote enzyme that unwinds the DNA helix at the replication fork, breaking the hydrogen bonds, to allow the resulting single strands to be copied
histone
any of several small, basic proteins most commonly found in association with the DNA in the chromatin of eukaryotes
intron
a segment of a gene situated between exons that is removed before the translation of messenger RNA and does not function in coding for protein synthesis
lagging strand
the strand of the DNA double helix that, because of its orientation that is opposite to the working orientation of DNA polymerase III, is synthesised in a series of short fragments known as Okazaki fragments
leading strand
DNA strand being replicated by continuous polymerisation at the 3′ growing tip
nucleosome
a structural, basic bead-like unit of DNA packing in eukaryotes, consisting of a sequence of DNA wound around a protein core composed of eight histones
nucleotides
the building blocks of a nucleic acid, consisting of a carbon sugar covalently bonded to a nitrogenous base and a phosphate group
primer
a segment of DNA or RNA that is complementary to a given DNA sequence and that is needed to initiate replication by DNA polymerase
replication fork
a site on a DNA molecule at which the unwinding of the helices and synthesis of daughter molecules are both occurring during DNA replication
tandem repeats
copies of genes repeated one after another along a chromosome
telomere
a region of repetitive nucleotide sequences at each end of a chromatid that is involved in the replication and stability of DNA molecules protecting the end of the chromosome from deterioration
x-ray diffraction
an analytical method in which X-rays change direction on contact with matter, resulting in changes in radiation intensity, that is used to determine the three-dimensional arrangement of atoms
5’ to 3’ direction
the only direction that DNA polymerase can synthesise DNA; it does so by adding nucleotides to the 3′ end of a DNA strand
DNA methylation
the modification of a strand of DNA after it is replicated, in which a methyl (CH3) group is added and is one of the methods used to regulate the expression of genes
exon
sequence of DNA that codes information for protein synthesis that is transcribed to messenger RNA
gene expression
conversion of the information from the gene into mRNA via transcription and then to protein via translation resulting in the phenotypic manifestation of the gene
genome
total genetic contents of an organism
non-coding DNA
components of an organism’s DNA that do not encode protein sequences; some non-coding DNA is transcribed into functional non-coding RNA molecules while others are not transcribed