AP Biology Chapter 17 Quiz Flashcards
Premise that a gene is a segment of DNA that codes for one polypeptide
One gene–one polypeptide hypothesis
Synthesis of RNA on a DNA template
Transcription
A type of RNA, synthesized from DNA, that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein
Messenger RNA (mRNA)
The synthesis of a polypeptide using the genetic information encoded in an mRNA molecule
Translation
A cell organelle constructed in the nucleolus and functioning as the site of protein synthesis in the cytoplasm
Ribosome
Modification of RNA before it leaves the nucleus, a process unique to eukaryotes
RNA processing
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 template for ordering the sequence of nucleotides in an RNA transcript
Template strand
The way a cell′s mRNA–translating machinery groups the mRNA nucleotides into codons
Reading frame
An enzyme that links together the growing chain of ribonucleotides during transcription
RNA polymerase
A specific nucleotide sequence in DNA that binds RNA polymerase and indicates where to start transcribing RNA
Promoter
In prokaryotes, a special sequence of nucleotides in DNA that marks the end of a gene. It signals RNA polymerase to release the newly made RNA molecule, which then departs from the gene
Terminator
A region of a DNA molecule that is transcribed into an RNA molecule
Transcription unit
A regulatory protein that binds to DNA and stimulates transcription of specific genes
Transcription factor
The completed assembly of transcription factors and RNA polymerase bound to the promoter
Transcription initiation complex
A promoter DNA sequence crucial in forming the transcription initiation complex
TATA box
The 5′ end of a pre–mRNA molecule modified by the addition of a cap of guanine nucleotide
5′ cap
The modified end of the 3′ end of an mRNA molecule consisting of the addition of some 50 to 250 adenine nucleotides
Poly–A tail
The removal of noncoding portions (introns) of the RNA molecule after initial synthesis
RNA splicing
A noncoding, intervening sequence within a eukaryotic gene
Intron
A coding region of a eukaryotic gene
Exon
A complex assembly that interacts with the ends of an RNA intron in splicing RNA, releasing the intron and joining the two adjacent exons
Spliceosome
An enzyme–like RNA molecule that catalyzes reactions during RNA splicing.
Ribozyme
A type of 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 (tRNA)
A specialized base triplet at one end of a tRNA molecule that recognizes a particular complementary codon on an mRNA molecule
Anticodon
An enzyme that joins each amino acid to the correct tRNA
Aminoacyl–tRNA synthetase
A violation of the base–pairing rules in that the third nucleotide (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 forms the structure of ribosomes
Ribosomal RNA (rRNA)
One of a ribosome′s three binding sites for tRNA during translation. The P site holds the tRNA carrying the growing polypeptide chain (P stands for peptidyl tRNA)
P site
One of a ribosome′s three binding sites for tRNA during translation. The A site holds the tRNA carrying the next amino acid to be added to the polypeptide chain (A stands for aminoacyl tRNA)
A site
One of a ribosome′s three binding sites for tRNA during translation. The E site is the place where discharged tRNAs leave the ribosome (E stands for exit)
E site
An aggregation of several ribosomes attached to one messenger RNA molecule
Polyribosome (polysome)
A stretch of amino acids on a polypeptide that targets the protein to a specific destination in a eukaryotic cell
Signal peptide
A protein–RNA complex that recognizes a signal peptide as it emerges from the ribosome
Signal–recognition particle (SRP)
A change in the DNA of a gene, ultimately creating genetic diversity
Mutation
A change in a gene at a single nucleotide pair
Point mutation
A type of point mutation; the replacement of one nucleotide and its partner in the complementary DNA strand by another pair of nucleotides
Base–pair substitution
The most common type of mutation, a base–pair substitution in which the new codon makes sense in that it still codes for an 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
(1) A deficiency in a chromosome resulting from the loss of a fragment through breakage
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 following nucleotides into codons
Frameshift mutation
A chemical or physical agent that interacts with DNA and causes a mutation
Mutagen
