How Genes direct the production of proteins Flashcards
what is mRNA and what is it used for
messenger RNA. translated into proteins
what is tRNA and what is it used for
transfer RNA. transfer amino acids to the growing peptide chain
what is rRNA and what is it used for
ribosomal RNA. encodes ribosomal proteins
what is microRNA used for
block translation of specific mRNAs and regulate gene expression
what are siRNA used for
small interfering RNA. turn off gene expression by directing the selective degradation of mRNAs
what is snoRNA and what is it used for
small nucelolar RNAs. process and chemically modify rRNAs
what are scaRNAs
small cajal RNAs. modify snoRNAs and snRNAs
what are noncoding RNAs used for
telomere synthesis, X- chromosome inactivation and protein transport into the ER
what is the order of abundant RNA type
rRNA > tRNA > mRNA
what are most protein coding genes transcribed as
RNA polymerase II
how does transcription start mechanism
TBP/TFIID binds to TATA box
- TFIIB binds to complex
-TFIIB binding leads to other factors binding and eventually RNA polymerase II
can RNA fold on itself
yes
what does TFIIB recognize and
recognizes BRE element and accurately positions RNA polymerase at the start site of transcription
what genes does RNA polymerase I work with
rRNA
what genes does RNA polymerase II work with
all protein coding genes, snoRNA, miRNA, siRNA, and most snRNA
what genes does RNA polymerase III work with
tRNA, rRNA, some snRNA
what are the order of events in mRNA processing
-capping
-splicing
-editing
-polyadenylation
-transport
what performs RNA splicing
spliceosome
what is the spliceosome made of
snRNAs with 7 protein subunits to form a SNP
what snRNAs are involved in splicing
U1, U2, U4, U5
what do the snRNAs do
provide proper base pairing with the mRNA
how does splicing occur
adenosine residues in the intron sequence undergoes nucleophilic attack at junction of intron and exon
how many genes does the human genome have
20,000-25,000
how many proteins does the human proteome have
250,000
what does the tropomyosin gene do in alternative splicing
splices out different exons to make specific tissues
where does capping occur
5’ end
where does polyadenylation occur
3’ end
when does the 5’ cap and splicing occur
as soon as the hnRNA emerges from the RNA polymerase
how does miRNA regulate translation
- bind to 3’ UTR of target mRNA to form a RISC
- suppress protein synthesis and/or induce mRNA degradation
- each miRNA can target mutliple different mRNAs
what is the mechanism of miRNA
dicer clips bubble to create miRNA that binds to proteins that make up argonaute protein complex, binds to mRNA then interferes with translation
what does commaless mean
read from beginning to end so reading frame is critical
what does degenerate mean
more than one codon makes the same amino acid
which base in the codon is less specific
the third
how many stop codons are ther
3
what is the only start codon
methionine- AUG
what is roberts syndrom
prenatal growth retardation, craniofacial abnormalities such as cleft lip and limb malformations
what does the mutation of ESCO2 in roberts syndrome lead to
decreased rDNA transcription
what determines what gets spliced out
nucleotides in intron sequence
