Chapter 7 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 threenucleotide 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
Unit of heredity containing the instructions that dictate the
characteristics or phenotype of an organism; in molecular
terms, a segment of DNA that directs the production of a
particular protein or functional RNA molecule.
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 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
G:8 Glossary
molecule is translated into the amino acid sequence of 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 nucleotide
promoter
DNA sequence that initiates gene transcription; includes
sequences recognized by RNA polymerase and its accessory
proteins.
protease
Enzyme that degrades proteins by hydrolyzing their peptide
bonds.