DNA Replication, Transcription, and Translation

Flashcards covering key vocabulary from a lecture on DNA replication, transcription, and translation.

DNA Helicase

The enzyme that denatures the double helix, splitting apart the double-stranded DNA at the origin of replication.

Replication Fork

The structure formed when DNA is being unzipped during replication.

RNA Primer

Short strand of RNA that serves as a starting point for DNA synthesis.

RNA Primase

Enzyme that creates a short strand of complementary RNA to give DNA polymerase something to hook nucleotides to.

DNA Polymerase III

DNA polymerase that follows the DNA helicase on the leading strand.

Leading Strand

The strand of DNA that is synthesized continuously in the same direction as the replication fork.

Lagging Strand

The strand of DNA that is synthesized discontinuously in the opposite direction of the replication fork.

DNA Polymerase I

Enzyme that removes RNA primers and replaces them with DNA.

Gaps

The areas where nucleotides are not connected with covalent bonds after RNA primers are replaced with DNA.

DNA Ligase

Enzyme that connects strands of nucleic acid, specifically filling in the gaps left after DNA polymerase I.

Transcription

Making RNA. Area of DNA that is transcribed; making an RNA complement out of a DNA sequence.

mRNA (messenger RNA)

RNA that carries instructions to a ribosome for protein synthesis.

tRNA (transfer RNA)

RNA that takes amino acids to the ribosome during translation.

rRNA (ribosomal RNA)

RNA that is an integral part of the ribosome structure.

Promoter

A specific DNA sequence that designates the start of a gene.

Terminator

The DNA sequence that tells RNA polymerase to stop transcription.

UTRs (untranslated regions)

Regions at the beginning and end of a gene that are not translated into protein. There is a five prime and a three prime.

Exons

Regions of a eukaryotic protein-coding gene that contain amino acid sequence information.

Introns

Regions of a eukaryotic protein-coding gene that do not contain amino acid sequence information.

Template Strand

The strand of DNA that the RNA polymerase makes a complement of; also called the noncoding strand.

Coding Strand

The strand of DNA that is not used by the RNA polymerase, and has a similar sequence to the mRNA; also called the non-template strand.

Pre-mRNA

The initial mRNA transcript produced in eukaryotes, which contains both introns and exons.

Spliceosome

A complex of proteins and RNA that removes introns from pre-mRNA.

Alternative Splicing

The process by which different messenger RNA sequences are made from the same gene by removing different exons and introns.

Five Prime Cap

The special chemical head added to the start of mRNA molecules which allows the RNA to last longer and signals for the RNA to leave the nucleus.

Poly A Tail

A chain of adenine nucleotides that is added to the end of the rna, that increases half-life and signals for the rna to leave the nucleus.

Small Subunit

Small subunit that associates with the front of the mRNA and scans down to AUG.

Translation

The process of making. also known as protein synthesis.

Large Subunit

Consist of the a site, p site, and e site, and attaches to the TRNA.

Codon

Three mRNA nucleotides that translate to one amino acid.

Start Codon (AUG)

The codon that signifies the start of translation. Codes for the amino acid methionine.

Methionine

The amino acid coded for by the start codon. First amino acid for every protein.

TRNA

RNA that has active site with three ribonucleotides that are the RNA complement of the appropriate codon.

Anticodon

The RNA complement of the codon. Found on tRNA.