virulent
describes a microorgamism that causes disease and that is highly infectious; strictly, refers only to viruses that reproduce by the lytic cycle.
transformation
the transfer of geneticmaterial in the form of DNA fragments from one cell to another or from one organism to another cell
bacteriophage
a virus that infects bacteria
nucleotide
in a nucleic-acid chain, a sub-unit that consists of a sugar, and a phosphate, and a nitrogenous base.
deoxyribose
a five-carbon sugar that is a componet of DAN nucleotides.
nitrogenous base
an organic base that contains nitrogen, such as a purine or pyrimidine; a subunit of a nucleotide in DAN and RNA.
purine
a nitrogenous base that has a double-ring structure; one of the two general categories of nitrogenous bases found in DAN and RNA; either adenine or guanine.
pyrimidine
a nitrogenous base that has a single-ring structure; one of the two general categories of nitrogenous bases found in DNA and RNA; thymine, cytosine, or uracil.
base-paring rules
the rules stating that cytosine pairs with guanine and adenine pairs with thymine in DNA, and that adenine pairs with uracil in RNA.
complementary base pair
the nucledotide bases in one strand of DNA or RNA that are paired with those of another strand; adenine pairs with thymine or uracil, and guanin pairs with cytosine.
base sequence
the order of nitrogenous bases on a chain of DNA
DNA replication
the process by which DNA is copied in a cell before a cell divides by mitosis, meiosis, or binary fission.
helicase
an enzyme that seperates DNA strands.
replication fork
the Y shaped region where the DNA splits.
DNA polymerase
an enzyme that catalyzes the formation of the DNA molecule.
semi-conserative replication
in each new DNA double helix, one strand is fromt he original molecule, and one strand is new.
mutation
a change in the nucleotide-base sequence of a gene or DNA molecule.
Ribonucleic acid (RNA)
a natural polymer that is present in all living cells and that plays a ro3le in protein synthesis.
transcription
the process of forming a nucleic acid by using another molecule synthesizing RNA by using one strand of a DNA molecule as a template.
translation
the portion of protein sythesis that takes place at ribosomes and that uses the codons in mRNA molecules to specify the sequence of amion acids in polypeptide chains.
protein synthesis
the formation of proteins by using information contained in DNA and carried by mRNA.
ribose
a five-carbon sugar present in RNA.
messenger RNA (mRNA)
carrie the genetic information from the nucleus into the cytosol.
ribosomal RNA (rRNA)
makes up ribosomes
transfer RNA (tRNA)
an RNA molecule that transfers amino acids to the growing end of a polypeptide chain during translation.
RNA polymerase
an enzyme that starts (catalyzes) the formation of RNA by using a strand of a DNA molecule as a template.
Promoter
a nucleotide sequence on a DNA molecule to which an RNA polymerase molecule binds, which initiates the transcription of a specific gene.
termintation signal
a specific sequence of nucleotides that marks the end of a gene.
genetic code
the rule that descirbes how a sequence of nucleotides, read in groups of three consecutive nucleodties (triplets) taht correspond to specific amino acids, specifies the amino acid sequence of a protein.
codon
in DNA,a three-nucleotie sequence that encodes an amino acid or signifies a start signal or a stop signal.
anticodon
a region of tRNA that consists of three bases complementary to the codon of mRNA.
genome
the complete genetic material contained in an individual.