Unit 6, Topic 3: Transcription and RNA processing Flashcards
(37 cards)
process through which messenger RNA forms on a template of DNA
transcription
processes that control the turning on or turning off of a gene
gene expression
strand of DNA that specifies the complementary mRNA molecule
template strand
three consecutive nucleotides in mRNA that specify the insertion of an amino acid or the release of a polypeptide chain during translation
codon
RNA that ensures the proper alignment of the mRNA and the ribosomes during protein synthesis and catalyzes the formation of the peptide linkage
rRNA
AKA ribosomal RNA
RNA that carries activated amino acids to the site of protein synthesis on the ribosome
tRNA
AKA transfer RNA
a methylated guanosine triphosphate (GTP) molecule that is attached to the 5’ end of a messenger RNA to protect the end from degradation
5’ cap
modification added to the 3’ end of pre-mRNAs to protect mRNA from degradation and assist mRNA export from the nucleus
Poly-A tail
RNA that carries information from DNA to ribosomes during protein synthesis
mRNA
AKA messenger RNA
sequence of triplet codons in mRNA that specify a particular protein; a ribosome shift of one or two nucleotides in either direction completely abolishes synthesis of that protein
reading frame
The mechanism that allows different protein products to be produced from one gene when different combinations of introns, and sometimes exons, are removed from the transcript.
alternative splicing
the process by which introns are removed from tthe RNA strand
RNA splicing
In eukaryotes, transcription occurs in _________.
the nucleus
True or false: the genetic code is read in groups of two nucleotides at a time called the doublet code.
False
It is read in groups of 3 (triplet code)
True or false: only the template strand of DNA is transcribed during transcription.
true
Fill in the blank: the mRNA nucleotide triplets are called (blank). These code for (blank).
codons, amino acid insertion/polypeptide chain
What is a promoter region?
a region of DNA where RNA polymerase begins to transcribe a gene.
Are promoter regions upstream or downstream of the gene?
upstream
What would be the immediate effect to transcription if a cell was exposed to a drug that mutated the promoter region?
RNA polymerase would not be able to bind to the DNA and transcription would not be able to occur.
Why do introns exist if they are just spliced out of the mRNA during pre-mRNA modifications?
so that a single gene is able to produce multiple proteins from the same gene with slightly different effects.
Why is redundancy in the genetic code important?
it minimizes the harmful effects that incorrectly placed nucleotides can have on protein synthesis.
Which triplets code for phenylalanine (phe)?
UUU, UUC
Which triplets code for leucine (leu)?
UUA, UUG, CUU, CUC, CUA, CUG
Which triplets code for isoleucine (Ile)?
AUU, AUC, AUA
