Kapitel 7 Flashcards
The production of different mRNAs (and proteins) from the same gene by splicing its RNA transcripts in different ways.
alternative splicing
During protein synthesis - an enzyme that attaches the correct amino acid to a tRNA molecule to form a “charged” aminoacyl-tRNA.
aminoacyl-tRNA synthetase
Set of three consecutive nucleotides in a transfer RNA molecule that recognizes - through base-pairing - the three-nucleotide codon on a messenger RNA molecule; this interaction helps to deliver the correct amino acid to a growing polypeptide chain.
anticodon
Group of three consecutive nucleotides that specifies a particular amino acid or that starts or stops protein synthesis; applies to the nucleotides in an mRNA or in a coding sequence of DNA.
codon
Segment of a eukaryotic gene that is transcribed into RNA and dictates the amino acid sequence of part of a protein.
exon
Proteins that assemble on the promoters of many eukaryotic genes near the start site of transcription and load the RNA polymerase in the correct position.
general transcription factors
Special tRNA that initiates the translation of an mRNA in a ribosome. It always carries the amino acid methionine.
initiator tRNA
Noncoding sequence within a eukaryotic gene that is transcribed into an RNA molecule but is then excised by RNA splicing to produce an mRNA.
intron
RNA molecule that specifies the amino acid sequence of a protein.
messenger RNA (mRNA)
The addition of multiple adenine nucleotides to the 3′ end of a newly synthesized mRNA molecule.
polyadenylation
DNA sequence that initiates gene transcription; includes sequences recognized by RNA polymerase.
promoter
Enzyme that degrades proteins by hydrolyzing their peptide bonds.
protease
Large protein machine that degrades proteins that are damaged - misfolded - or no longer needed by the cell; its target proteins are marked for destruction primarily by the attachment of a short chain of ubiquitin.
proteasome
One of the three possible ways in which a set of successive nucleotide triplets can be translated into protein - depending on which nucleotide serves as the starting point.
reading frame
RNA molecule that forms the structural and catalytic core of the ribosome.
ribosomal RNA (rRNA)
An RNA molecule with catalytic activity.
ribozyme
The modification of the 5′ end of a maturing RNA transcript by the addition of an atypical nucleotide.
RNA capping
Enzyme that catalyzes the synthesis of an RNA molecule from a DNA template using nucleoside triphosphate precursors.
RNA polymerase
Broad term for the modifications that a precursor mRNA undergoes as it matures into an mRNA. It typically includes 5′ capping - RNA splicing - and 3′ polyadenylation.
RNA processing
Process in which intron sequences are excised from RNA molecules in the nucleus during the formation of a mature messenger RNA.
RNA splicing
RNA molecule produced by transcription that is complementary to one strand of DNA.
RNA transcript
Hypothetical period in Earth’s early history in which life-forms were thought to use RNA both to store genetic information and to catalyze chemical reactions.
RNA world
RNA molecule of around 200 nucleotides that participates in RNA splicing.
small nuclear RNA (snRNA)
Large assembly of RNA and protein molecules that splices introns out of pre-mRNA in the nucleus of eukaryotic cells.
spliceosome
Process in which RNA polymerase uses one strand of DNA as a template to synthesize a complementary RNA sequence.
transcription
Small RNA molecule that serves as an adaptor that “reads” a codon in mRNA and adds the correct amino acid to the growing polypeptide chain.
transfer RNA (tRNA)
Process by which the sequence of nucleotides in a messenger RNA molecule directs the incorporation of amino acids into protein.
translation
Protein that promotes the proper association of ribosomes with mRNA and is required for the initiation of protein synthesis.
translation initiation factor
The principle that genetic information flows from DNA to RNA to protein.
central dogma
See transcription
DNA transcription
Protein that promotes the proper association of ribosomes with mRNA and is required for the initiation of protein synthesis.
initiation factor
Messenger RNA molecule to which multiple ribosomes are attached and engaged in protein synthesis.
polyribosome
See transcription
primary transcript
Degradation of a protein by means of a protease.
proteolysis
See primer
RNA primer
Complex made of RNA and protein that recognizes RNA splice sites and participates in the chemistry of splicing; together these complexes form the core of the spliceosome.
small nuclear ribonucleoprotein (snRNP)
Term loosely applied to any protein required to initiate or regulate transcription in eukaryotes. Includes transcription regulators as well as the general transcription factors.
transcription factor
