Chapter 7 Vocab Flashcards
alternative splicing
The production of different mRNAs (and proteins) from the same gene by splicing its RNA transcripts in different ways
aminoacyl-tRNA synthetase
During protein synthesis, an enzyme that attaches the correct amino acid to a tRNA molecule to form a “charged” aminoacyl-tRNA.
anticodon
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.
codon
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.
exon
Segment of a eukaryotic gene that is transcribed into RNA and dictates the amino acid sequence of part of a protein.
gene expression
The process by which a gene makes a product that is useful to the cell or organism by directing the synthesis of a protein or an RNA molecule with a characteristic activity
general transcription factors
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.
Genetic Code
Set of rules by which the information contained in the nucleotide sequence of a gene and its corresponding RNA molecule is translated into the amino acid sequence in a protein.
initiator tRNA
Special tRNA that initiates the translation of an mRNA in a ribosome. It always carries the amino acid methionine.
intron
Noncoding sequence within a eukaryotic gene that is transcribed into an RNA molecule but is then excised by RNA splicing to produce an mRNA.
messenger RNA (mRNA)
RNA molecule that specifies the amino acid sequence of a protein.
polyadenylation
The addition of multiple adenine nucleotides to the 3 end of a newly synthesized mRNA molecule.
promoter
DNA sequence that initiates gene transcription; includes sequences recognized by RNA polymerase.
protease
Enzyme that degrades proteins by hydrolyzing their peptide bonds.
proteasome
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.
ribosomal RNA (rRNA)
RNA molecule that forms the structural and catalytic core of the ribosome.
ribosome
Large macromolecular complex, composed of ribosomal RNAs and ribosomal proteins, that translates messenger RNA into protein.
ribozyme
An RNA molecule with catalytic activity.
RNA
Molecule produced by the transcription of DNA; usually single-stranded, it is a polynucleotide composed of covalently linked ribonucleotide subunits. Serves a variety of structural, catalytic, and regulatory functions in cells.
RNA capping
The modification of the 5 end of a maturing RNA transcript by the addition of an atypical nucleotide.
RNA polymerase
Enzyme that catalyzes the synthesis of an RNA molecule from a DNA template using nucleoside triphosphate precursors.
RNA processing
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 splicing
Process in which intron sequences are excised from RNA molecules in the nucleus during the formation of a mature messenger RNA.
RNA transcript
RNA molecule produced by transcription that is complementary to one strand of DNA.
RNA world
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.
small nuclear RNA (snRNA)
RNA molecule of around 200 nucleotides that participates in RNA splicing.
spliceosome
Large assembly of RNA and protein molecules that splices introns out of pre-mRNA in the nucleus of eukaryotic cells.
transcription
Process in which RNA polymerase uses one strand of DNA as a template to synthesize a complementary RNA sequence.
transfer RNA (tRNA)
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.
translation
Process by which the sequence of nucleotides in a messenger RNA molecule directs the incorporation of amino acids into protein.
translation initiation factor
Protein that promotes the proper association of ribosomes with mRNA and is required for the initiation of protein synthesis.
