Chapter 14 Vocab Flashcards
the process by which DNA directs the synthesis of proteins or, in some cases, just RNAs
gene expression
the synthesis of RNA using a DNA template
transcription
a type of RNA, synthesized using a DNA template, that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein
messenger RNA
the synthesis of a polypeptide using the genetic information encoded in an mRNA molecule
translation
a complex of rRNA and protein molecules that functions as a site of protein synthesis in the cytoplasm
ribosome
an initial RNA transcript; also called pre-mRNA when transcribed from a protein-coding gene
primary transcript
a set of three-nucleotide-long words that specify the amino acids for polypeptide chains
triplet code
the DNA strand that provides the pattern for ordering the sequence of nucleotides in an RNA transcript
template strand
a three nucleotide sequence of mRNA that specifies a particular amino acid or termination signal
codon
on the mRNA, the triplet grouping of ribonucleotides used by the translation machinery during polypeptide synthesis
reading frame
an enzyme that links ribonucleotides into a growing RNA chain during transcription
RNA polymerase
a specific nucleotide sequence in DNA that binds RNA polymerase, positioning it to start transcribing RNA at the appropriate place
<promoter
a sequence of nucleotides in DNA that marks the end of a gene and signals RNA polymerase to release the newly made RNA molecule and detach from the DNA
terminator
a region of DNA that is transcribed into an RNA molecule
transcription unit
a regulatory protein that binds to DNA and affects transcription of specific genes
transcription factor
the completed assembly of transcription factors and RNA polymerase bound to the promoter
transcription initiation complex
a DNA sequence in eukaryotic promoters crucial in forming the transcription initiation complex
TATA box
modification of RNA transcripts, including splicing out of introns, joining together of exons, and alteration of the 5’ and 3’ ends
RNA processing
a modified form of guanine nucleotide added onto the nucleotide at the 5’ end of a pre-mRNA molecule
5’ cap
a sequence of 50-250 adenine nucleotides added onto the 3’ end of a pre-mRNA molecule
poly A tail
after synthesis of a eukaryotic primary RNA transcript, the removal of portions (introns) of the transcript that will not be included in the mRNA
RNA splicing
a noncoding, intervening sequence within a primary transcript that is removed from the transcript during RNA processing
intron
a sequence within a primary transcript that remains in the RNA after RNA processing
exon
a large complex made up of proteins and RNA molecules that splices RNA by interacting with the ends of an RNA intron, releasing the intron and joining the two adjacent exons
spliceosome
an RNA molecule that functions as an enzyme, catalyzing reactions during RNA splicing
ribozyme
a type of eukaryotic gene regulation at the RNA-processing level in which different mRNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns
alternative RNA splicing
an independently folding part of a protein
domain
an RNA molecule that functions as an interpreter between nucleic acid and protein language by picking up specific amino acids and recognizing the appropriate codons in the mRNA
transfer RNA
a nucleotide triplet at one end of a tRNA molecule that recognizes a particular complementary codon on an mRNA molecule
anticodon
flexibility in the base-pairing rules in which the nucleotide at the 5’ end of a tRNA anticodon can form hydrogen bonds with more than one kind of base in the third position (3’ end) of a codon
wobble
the most abundant type of RNA, which together with proteins makes up ribosomes
ribosomal RNA
the place on a ribosome that holds the tRNA carrying the next amino acid to be added to the polypeptide chain
A site
the place on a ribosome that holds the tRNA carrying the growing polypeptide chain
P site
the place on a ribosome where discharged tRNAs leave the ribosome
E site
a group of several ribosomes attached to, and translating, the same messenger RNA molecule
polyribosome
<p>a sequence of about 20 amino acids at or near the leading (amino) end of a polypeptide that targets it to the endoplasmic reticulum or other organelles in a eukarytoic cell</p>
signal peptide
a protein-RNA complex that recognizes a signal peptide as it emerges from a ribosome and helps direct the ribosome to the endoplasmic reticulum (ER) by binding to a receptor protein on the ER
signal recognition particle
a change in the nucleotide sequence of an organism’s DNA, ultimately creating genetic diversity
mutation
a change in a gene at a single nucleotide pair
point mutation
a type of point mutation where one nucleotide and its partner in the complementary DNA strand are replaced by another pair of nucleotides
base pair substitution
a base-pair substitution that results in a codon that codes for a different amino acid
missense mutation
a mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein
nonsense mutation
a mutation involving the addition of one or more nucleotide pairs to a gene
insertion
a mutational loss of one or more nucleotide pairs from a gene
deletion
a mutation occurring when the number of nucleotides inserted or deleted is not a multiple of three, resulting in the improper grouping of the subsequent nucleotides into codons
frameshift mutation
a chemical or physical agent that interacts with DNA and causes a mutation
mutagen
An enzyme that joins each amino acid to the correct tRNA.
aminoacyl-tRNA synthetase
