Chap. 17 (Vocab) Flashcards
Gene Expression
Information encoded in a gene is turned into a function
Transcription
Synthesis of RNA from DNA
Messenger RNA (mRNA)
Carries protein information from DNA in nucleus to ribosome, located in cytoplasma
Translation
Synthesis of polypeptides from mRNA
Ribosome
Cellular structure composed of RNA
Primary Transcript
Initial RNA molecule produced directly from DNA transcription
Triplet Code
3-nucleotide sequences specify for sequence of amino acids for polypeptide chain
Templet Strand
Strand of DNA that serves as templet for synthesis of RNA
Codons
3-nucleotide sequence of DNA or RNA that corresponds to a specific amino acid or stop signal during protein synthesis
Coding Strand
DNA strand that contains genetic information and is used to create messenger RNA (mRNA) and protein
Reading Frame
Codon sets that determine how genetic info. is translated into amino acids
RNA Polymerase
Enzyme that transcribes DNA into RNA
Promoter
DNA sequence that acts as RNA polymerase biding site
Terminator
In bacteria, the sequence that signals the end of transcription
Transcription Unit
Segment of DNA that is transcribed into an RNA molecule by RNA polymerase
Start Point
Location on a DNA molecule where the process of transcription begin
Transcription Factors
Protein that binds to DNA sequences + affects transcription of specific genes
Transcription Initiation Complex
Completed assembly of transcription factors + RNA polymerase bounds to promoter
TATA Box
DNA sequence located in the promoter region of a gene that acts as a binding site for transcription factors
RNA Processing
Series of modifications that occur to a newly transcribed RNA molecule to transform it into functional RNA molecule
Poly-A Tail
Sequence of 50-250 adenine nucleotides added onto 3’ end of pre-RNA
5’ Cap
Modified guanine nucleotide added to the 5’ end of a mRNA
RNA Splicing
Pre-mRNA is processed and transformed into mRNA
Introns
Noncoding DNA sequences within a gene that are removed before the final RNA transcript is made
Exons
Coding segments of a gene that are translated into protein
Spliceosome
Complex of RNA + proteins that remove introns from pre-messenger RNA (pre-mRNA) and join exons
Ribozymes
RNA molecule that functions as enzyme
- Like intro that catalyzes its own removal
Alternative RNA Splicing
Exons are joined in different combinations, leading to different, but related, mRNA transcripts
Domain
Amino acid sequence in a protein that is associated with a particular function
Transfer RNA (tRNA)
RNA molecule that acts as an adaptor, carrying a specific amino acid to the ribosome
Anticodon
3-nucleotide sequence of tRNA that binds to codons from mRNA
Wobble
Same amino acid may be encoded by multiple codons
Ribosomal RNA (rRNA)
Part of the ribosome that helps translate mRNA into proteins.
P Site
Holds the tRNA carrying the growing polypeptide chain
A Site
Holds the tRNA carrying the next amino acid to be added to the chain
E Site
Exit for tRNAs to leave the ribosome
Initiation
RNA polymerase enzyme binds to the promoter region of the gene, which signals the DNA to unwind
Elongation
RNA polymerase reads the DNA strand and adds nucleotides to the growing mRNA strand
Termination
RNA polymerase transcribes a terminator sequence in the DNA, ending transcription. The mRNA strand detaches from the DNA
Single Peptide
Short sequence of amino acids that controls how proteins are secreted and moved within a cell
Signal-Recognition Particle (SRP)
Recognizes + binds to signal sequence on synthesized protein as it emerges from the ribosome, targeting it to the ER to ensure proper protein sorting
Polyribosomes
Group of ribosomes that are attached to a messenger RNA (mRNA) molecule
Mutations
Change in DNA sequence of organism
Point Mutations
Genetic change where a single nucleotide base within a DNA sequence is altered (just one letter altered)
Nucleotide-pair Substitution
Replacement of one nucleotide and its partner with another pair of nucleotides (Same as point mutation)
Silent Mutation
Change in DNA sequence that does not result in a change to the amino acid sequence
Missense Mutation
Single change in the DNA sequence results in a different amino acid being incorporated into the protein
Nonsense Mutation
Genetic alteration where a DNA sequence changes, causing a premature “stop codon” to be produced
Insertions
Genetic mutation where one or more nucleotides are added to a DNA sequence
Deletions
Genetic change that involves the absence of a segment of DNA
Frameshift Mutation
Inserted or deleted that causes change in how reading frame is read, resulting in a completely different amino acid sequence
Mutagens
Chemical, physical, or biological agent that causes mutations in DNA
