Transcription
What is transcription?
The synthesis of RNA (mRNA) under the direction of DNA.
What is exon shuffling?
When different exons are moved around because they code for different domains in a protein.
What does mRNA stand for?
messenger RNA
Is the ribosome a membrane-bound organelle?
No
What is the RNA world hypothesis?
Idea that the first organisms used RNA as their genetic material and catalysts (ribozymes) for chemical reactions because RNA can bind to and replicate itself.
The promoter sequence of transcription is?
Stretch of DNA where RNA polymerase attaches to begin transcription.
What is translation?
The synthesis of proteins by the ribosome using mRNA instructions.
What are the two alterations done the ends of pre-mRNA?
A 5' cap and a poly-A tail
What does the E site of a ribosome stand for and do?
The Exit site is where discharged tRNAs leave the ribosome.
What is wobble?
Flexible pairing at the 3rd base of a codon that lets some tRNAs bind to multiple codons.
What molecule untwists DNA in transcription and adds new nucleotides to form RNA?
RNA polymerase
What is triplet code? (Hint: Codons)
Each mRNA nucleotide base triplet codes for one of the 20 amino acids.
What molecule splices together exons?
The spliceosome
What does the A site of a ribosome stand for and do?
The aminoacyl-tRNA binding site holds the tRNA that carries the next amino acid to be added to the polypeptide chain.
What are point mutations?
Chemical changes in just one base pair of a gene.
How does transcription termination occur in eukaryotes?
Polymerase keeps going after the pre-mRNA is cleaved from the new mRNA and it eventually falls off the DNA
What enzyme facilitates the match between tRNA and an amino acid?
Aminoacyl-tRNA synthetase
What is RNA splicing?
The cutting out of introns (noncoding regions) and splicing together of exons (coding regions).
What does the P site of a ribosome stand for and do?
The Peptidyl-tRNA binding site holds the tRNA that carries the growing polypeptide chain.
What are the two populations of ribosomes?
Free ribosomes and Bound ribosomes
What is the transcription initiation complex?
The completed assembly of transcription factors (mediate the binding of RNA polymerase and the initiation of transcription) and RNA polymerase II bound to a promoter.
What does tRNA stand for and do?
Transfer RNA helps the ribosome translate mRNA into protein using its specific amino acid on one end and anticodon on the other end.
Why are the ends of pre-mRNA altered?
To protect RNA from degradation by hydrolytic enzymes, facilitate the transport of RNA through nuclear pores, and to help the molecule attach to the ribosome for translation.
What is rRNA and what does it do?
Ribosomal RNA plays a catalytic and structural role in the ribosome, so it makes up the two subunits of the ribosome alongside proteins.
The stop codon in mRNA reaches ribosome A, which accepts a release factor protein that causes the addition of H2O instead of an amino acid and releases the polypeptide.