45 % non-coding DNA formed by Transposons or Jumping genes; 24 % Introns (within genes); pseudogenes – non-functional genes due to accumulated mutation
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WHy might 'junk' DNA be vital
Limiting chance of mutation occurring in coding region; activate or down regulate genes
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What are the non-coding sequence in eukaryotic genes
Introns
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how many transcription factors are needed to build a Preinitiation Complex (PIC)
7
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What is spliceosome made of
small nuclear ribonuleoproteins–snRNPs(“snurps”); snRNP –small nuclear RNA(snRNA) combined with protein molecules; snRNAs are ribozymes–RNA with a catalytic functio
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Level at which a gene is expressed in a cell or organism needs to change
to meet demands for the gene product; or prevent excess product being synthesised; change activity of the protein
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how to control gene expression
transcription; RNA processing (slicing); mRNA kept in nucleus/ transported to specific location; translation; protein life span; protein activity controlled (phosphylation/dephosphrylation)
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how long does it take for gene to be transcribed with a strong promoter
every 2 seconds
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how long does it take for gene to be transcribed with a weak promoter
every 10 seconds
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how long can a gene be transcribed for
as long as the TFs are bound to the promoter –multiple RNA strands produced
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How does Metal-Responsive Transcription Factor (MTF -1) regulate heavy metals in cells
MTF –1 binds to DNA at specific tetal Response Element(MRE); Activated MTF-1 binds to DNA were this sequence occursMRE has core consensus (common sequence of bases);
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What kind of transcription factor is Metal-Responsive Transcription Factor (MTF -1)
both a Transcription Activator and Transcription Repressor
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How is Metal-Responsive Transcription Factor (MTF -1) activated
resides in an inactive form in cytoplasm; Binding of 7 Zn2+ to a specific site on the protein activates MTF -1; Cu+also activates MTF-1 when 4 Cu+ bind to a site distinct from Zn2+ • MTF-1 is also activated by Cd2+, the mechanism is unknown
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Effects of MTF -1 on gene expression (fruit flies)
Regulates at least 43 genes; Down regulates influx active transport proteins; Up regulates efflux active transport proteins; Up regulates the metallothionein gene
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What is alternative splicing
exons can be spliced together different ways producing ‘alternative’ versions of mRNA; Alternatives code for related, but different proteins; one gene can produce two or more protein product
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broad categories of translation level control mechanisms
Localisation in the cytoplasm mRNA translation control mRNA lifespan
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How is Translation level control localised in the cytoplasm
mRNA transported; 1 mRNA molecule = many protein molecules •Thus easier to move mRNA than protein
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How is MicroRNA (miRNA) part of translation level control
Specific proteinsalong with micro miRNAinhibit mRNA translation into proteins •Proteins + miRNA forms RNA-induced silencing complex (RISC) •RISC ‘patrols’ cytoplasm looks for mRNA with complementary base sequence to the miRNA in the RISC
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Other cards in this set
Card 2
Front
WHy might 'junk' DNA be vital
Back
Limiting chance of mutation occurring in coding region; activate or down regulate genes
Card 3
Front
What are the non-coding sequence in eukaryotic genes
Back
Card 4
Front
how many transcription factors are needed to build a Preinitiation Complex (PIC)
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