Chapter 12 Part 2 Flashcards
Promoter
In an operon, a sequence of DNA where RNA polymerase binds prior to transcription.
RNA Polymerase
During transcription, an enzyme that creates an mRNA transcript by joining nucleotides complementary to a DNA template.
mRNA Transcript
mRNA molecule formed during transcription that has a sequence of bases complementary to a gene.
Exons
Segment of mRNA containing the protein coding portion of a gene that remains within the mRNA after splicing has occurred.
Introns
Intervening sequence found between exons in mRNA; removed by RNA processing before translation.
Ribozyme
RNA molecule that functions as an enzyme that can catalyze chemical reactions.
Anticodon
Three-base sequence in a transfer RNA molecule base that pairs with a complementary codon in mRNA.
Wobble Hypothesis
Ability of the tRNAs to recognize more than one codon; the codons differ in their third nucleotide.
Polyribosome
String of ribosomes simultaneously translating regions of the same mRNA strand during protein synthesis.
Initiation
First stage of translation in which the translational machinery binds an mRNA and assembles.
Elongation
Middle stage of translation in which additional amino acids specified by the mRNA are added to the growing polypeptide.
Translocation
Movement of a chromosomal segment from one chromosome to another nonhomologous chromosome, leading to abnormalities–e.g., Down syndrome.
Termination
End of translation that occurs when a ribosome reaches a stop codon on the mRNA that it is translating, causing release of the completed protein.
Proteomics
Study of the complete collection of proteins that a cell or organism expresses.
Euchromatin
Chromatin with a lower level of compaction and therefore accessible for transcription.
