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one of two alternate forms of a gene that can have the same locus on homologous chromosomes and are responsible for alternative traits
strands run in opposite direction in the arrangement of the sugar-phosphate backbones in a DNA double helix.
in a eukaryotic cell, one of the structures in the nucleus that are made up of DNA and protein; in a prokaryotic cell, the main ring of DNA.
a specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code information for a particular amino acid
Mechanism for repair of damaged DNA by several enzymes that do not require light for activation; they excise defective nucleotide sequences and replace them with DNA complementary to the unaltered DNA strand
point mutation; chemical mutagen/agent that removes an amino group from base of normal DNA
Two adjacent pyrimidines bonded together in a DNA strand, usually as a result of exposure to ultraviolet rays
enzyme that moves along behind the replication fork to makes a long strand of DNA; attaches at the replication fork; "proofreads" new DNA strands
the inhibition of a enzyme in a metabolic pathway by the final product of that pathway
produced by mutagens (chemical agents or radiation); increases mutation rate above spontaneous mutation rate
backward; new strand of DNA formed in short, discontinuous DNA setments during DNA replication
new strand of DNA formed as a continuous strand during DNA replication; easier direction for polymerase to add neucleotides
a chemical mutagen that can add alkyl groups to DNA bases, altering their shapes and causing errors in the base paring
test used to determine whether a particular substance is mutagenic, based on its ability to induce jmutatjions in auxotrophic bacteria`
a chemical mutagen similar in molecular structure to one of the nitrogenous bases found in DNA that causes point mutation
an enzyme that is synthesized continuously regardless of the nutrients available to the organism
mechanism by which the presence of a particular metabolite reppresses the genes coding for enzymes used in its synthesis
a test used to determine that resistance to chemical substances occurs spontaineously rather than being induced
messeger RNA (mRNA)
a type of RNA that carries the information from DNA to dictate the arrangement of amino acids in a protein
aka terminator codon; a set of three bases in a gene (or mRNA) that does not code for an amino acid
one of the short, discontinuous DNA segments formed on the lagging strand during DNA replication
polymerase chain reaction
technique that produces a billion or more identical copies of a DNA fragment without needing a celel
an enzyme that binds to one strand of exposed DNA during transcription and catalyzes the synthesis to RNA from the DNA template
process in replication that ends up with a strand of old (parent) DNA and new DNA
the first codon in a molecule of mRNA which begins the sequence of amino acids in protein synthesis
aka terminator codon; the last codon to be translated in a molecule of mRNA, causing the ribosome to release from the mRNA
transfer RNA (tRNA)
function is to transfer amino acids from the cytoplasm to the ribosomes for placement in a protein molecule; link between the codons and corresponding amino acids; each has an anticodon
steps to transfer DNA to protein
replication (get DNA), transcription (get RNA), translation (get protein)
messenger RNA (mRNA)
carries information from DNA for synthesis of protein; has codons; attaches to ribosomes
removes an amino acid group from a nitrogenous group; results to a point mutation; ex; nitrous acid that is added to hot dogs
adds alkyl group which results in incorrect pairing; results to a point mutation; ex: mustard gas
inserts DNA ladder between backbones to form a new rung; distorts helis; causes framshift mutation;
light repair (photoreactivation)
uses an enzyme that is activated by visivle light and breaks bonds between pyrimidines of a dimer
highly reactive molecule, atom or ion that in turn attackS other cell molecules, including DNA
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