20 genes and the genome Flashcards
how do we define the ‘coding strand’?
the strand that has the PROMOTER regionat its 5’ end
what is the complimentary strand?
the template strand for RNA synthesis - serves as the template for RNA synthesis. READ from 3’->5’ so RNA is synthesized 5’ to 3’
what is the function of the regulatory regiosn?
to determine the timing and amount of RNA synthesis?
what is the function of the coding sequences?
transcribed into RNA - mRNA, rRNA and tRNA
how does the coding strand relate to the RNA?
same sequence of bases except T->U
how does the template strand relate to the RNA?
it is complementary
what are the differences between genes in eukaryotes and prokaryotes?
eukaryotes have exons and introns. genes are translated into a single protein that may be cleaved by proteases. no introns in prokaryotes, and some genes can form a single strand of mRNA that’s translated into individual proteins
what are repeat DNA sequences?
they are derived from transposable elements ie. inactive remnants of ancient viruses
what to repeat DNA sequences likely do?
could be protective for genes against mutations by irradiation or chemicals. are a template for siRNA (short interfering RNA) which helps to regulate gene expression
8% of the human genome is what?
3% SSR, 5% duplications of large DNA segments
45% of the human genome is what?
transposons - mobile genetic elements
what are the short and long term effects of transposons?
short term: variation of phenotypic expression, long term: evolution
how do transposons move within the genome?
encode transposases: enzymes that allow their transposition
what are the two major types of transposon?
DNA transposons and retrotransposons (LINES and SINES)
what’s the deal with DNA transposons?
CUT AND ASTE, inactive in the human genome
