BIOL 1201 Chp 17 Vocab

Gene expression

The process by which DNA directs protein synthesis.

Transcription

The synthesis of RNA using information in DNA.

mRNA

The product of transcription, used for translation to create the protein.

Translation

The synthesis of a polypeptide, using information in the mRNA.

Ribosomes

Proteins that serve as the sites of translation.

Primary transcript

The initial RNA transcript from any gene prior to processing.

Triplet code

A series of nonoverlapping, three-nucleotide words read to put the correct amino acids in the order for proteins.

Codons

The mRNA base triplets.

Coding strand

The non-template strand.

Reading frame

Correct groupings

RNA polymerase

catalyzes RNA synthesis.

Start point

location where transcription begins.

Transcription factors

help guide the binding of RNA polymerase and the initiation of transcription.

Transcription initiation complex

The completed assembly of transcription factors and RNA polymerase II.

TATA box

The promoter for eukaryotes.

RNA processing

when enzymes in the eukaryotic nucleus modifies pre-mRNA ​

5’ cap

Modification of the 5’ end of mRNA.

Poly-A-tail

The modified end of the 3’ end of mRNA.

RNA splicing

when introns are removed, and exons joined​

Introns

The non-coding segments in a gene.

Exons

The expressed regions of a gene.

Spliceosomes

Proteins responsible for removing introns and joining exons.

Ribozymes

Catalytic RNA molecules that function as enzymes and can splice RNA.

Alternative RNA splicing

When different regions of the gene are used as introns and exons depending on expression requirements.

Domains

Parts of proteins that are modulated in their architecture.

Transfer RNA (tRNA)

A type of RNA that transfers amino acids to the growing polypeptide in a ribosome.

Anticodon

the anticodon base-pairs with a complementary codon on mRNA​

Aminoacyl-tRNA synthetase

An enzyme that correctly matches tRNA and amino acid.

Wobble

Flexible pairing at the third base of a codon.

Ribosomal RNAs

Included in ribosomal subunits to create the ribosomal complex.

P-site

holds the tRNA that carries the growing polypeptide chain​

A site

holds the tRNA that carries the next amino acid to be added to the chain​

E site

the exit site, where discharged tRNAs leave the ribosome​

Signal peptide

a sequence of about 20 amino acids at or near the leadingend of the polypeptide​

Signal recognition particle

binds to the signal peptide and escorts theribosome to a receptor protein built into the ER membrane​

Polyribosome (polysome)

a complex of multiple ribosomes that are translating a single piece of mRNA​

Mutations

Changes in genetic information.

Point mutations

Changes in just one nucleotide pair of a gene.

Nucleotide pair substitution

Replaces one nucleotide and its partner with another nucleotide pair.

Silent mutations

no effect on the amino acid produced by a codon becauseof redundancy in the genetic code​

Missense mutations

still code for an amino acid, but not the correct aminoacid​

Nonsense mutations

change an amino acid codon into a stop codon; mostlead to a nonfunctional protein​

Insertions

Added nucleotides create a frameshift mutations.

Deletions

Deleted nucleotides creates a frameshift mutations.

Mutagens

Physical or chemical agents that can cause mutations.

Frameshift mutations

where the codons no longer are able to be read in thecorrect order because of an insertion or deletion​