Biology Chapter 15: Genes

Front 1

one gene-one polypeptide

Back 1

hypothesis that genes specify the strucure of enzymes, and that each gene encodes the structure of one enzyme

Front 2

transcription

Back 2

the enzyme-catalyzed assembly of an RNA molecule complementary to a strand of DNA

Front 3

translation

Back 3

the assembly of a protein on the ribosomes, using mRNA to specify the order of amino acids

Front 4

codon

Back 4

the basic unit of the genetic code; a sequence of three adjacent nucleotides in DNA or mRNA that codes for one amino acid

Front 5

reading frame

Back 5

the correct succession of nucleotides in triplet codons that specify amino acids on translation; is established by the first codon in the sequence as there are no spaces in the genetic code

Front 6

mRNA

Back 6

the RNA trancribed from structural genes; RNA molecules complementary to a portion of one strand of DNA, which are translated by the ribosomes to form protein

Front 7

rRNA

Back 7

a class of RNA molecules found, together with characteristic molecules found, together with characteristic proteins, in ribosomes; transcribed from the DNA of the nucleolus

Front 8

tRNA

Back 8

a class of small RNAs (about 80 nucleotides) with two functional sites; at one site, an "activating enxyme" adds a specific amino acid, while the other site carries the nucleotide triplet (anticodon) specific for that amino acid

Front 9

RNA polymerase

Back 9

an enzyme that catalyzes the assembly of an mRNA molecule, the sequence of which is complementary to a DNA molecule used as a template

Front 10

template strand

Back 10

the DNA strand that is used as a template in transcription; this strand is copied to produce a complemnetary mRNA trancript

Front 11

intron

Back 11

portion of mRNA as transcribed from eukaryotic DNA that is removed by enzymes before the mature mRNA is translated into protein

Front 12

exon

Back 12

a segment of DNA htat is both transcribed into RNA and translated into protein