Topic 6.3 - Transcription and RNA Processing 𖦹⋆｡°✩ Flashcards
how does genetic information flow
from DNA -> RNA -> protein
where is genetic information typically stored
in DNA molecules
what are RNA molecules used for
to facilitate protein synthesis using DNA information
what do ribosomes do
contain RNA and assemble proteins
what is transcription
the process in which an enzyme directs the formation of an mRNA molecule
what happens during transcription
DNA molecules are separated
what are the two strands being synthesized
the coding and non-coding strand
where is the gene targeted for transcription located
the coding strand
how does RNA polymerase synthesize mRNA
synthesizes mRNA in the 5’-3’ direction by reading the template in the 3’-5’ direction
what is mRNA
the transcribed copy of a particular gene
what are the types of RNA molecules
༻mRNA
༻ tRNA
༻ rRNA
what is the purpose mRNA
carries genetic information from DNA -> ribosomes. this information is used to direct protein synthesis at the ribosomal site
what is a codon
a 3-base sequence found on mRNA
what is the purpose of tRNA
recruited to the ribosomes to help create a specific polypeptide sequence as directed by mRNA
what do tRNA molecules carry
a specific amino acid
what is an anti-codon
a 3-base sequence on tRNA
what will the correct base pairing of anti-codons and codons result in
the release and addition of an amino acid to a growing polypeptide
what is rRNA
functional units of ribosomes responsible for protein assembly
what is the purpose of rRNA
༻base pairing of codons and anti-codons occurs in the ribosome
༻ creates primary polypeptides as tRNA releases amino acids
where do enzyme-regulated modifications occur
in the mRNA transcript (in eukaryotes)
what is the purpose of the addition of a poly-A tail
increases stability and helps with exporting from nucleus (100-200 A nucleotides)
where is the poly-A tail added
the 3’ end
what is the purpose of the GTP cap
protects transcript and helps ribosome attach to mRNA
what are introns
sequences of an mRNA transcript that do NOT code for amino acids. they are easily excised during RNA processing
what is not included in the mature mRNA transcript
introns
what are exons
sequences of an mRNA transcript that DO code for amino acids. these sequences are retained during RNA processing
are different exons connected in the mature mRNA transcrips
yes
what is alternative splicing
the process of splicing introns and connected retained exons in the mature mRNA transcript
how can different mRNA transcripts be produced
different mRNA transcripts can be produced from one primary transcript and exons can be retained in different variations
can different mRNA transcripts lead to different proteins
yes
what is a promoter
the nucleotide sequence that lies just before the gene and allows for the binding of RNA polymerase
