lecture 23 Flashcards
gene complexity and structure
what is the C value paradox?
excess DNA is present in the genome that does not seem to be essential for the development or evolutionary divergence of an organism
what paradox does the onion test refer to?
C-value paradox
what is C-value?
genome size
what is the g-value paradox?
the number of genes doesn’t have a correlation with organismal complexity
how are humans more complex than other organisms that have more DNA?
through alternative splicing and transcription factors
where does highly repetitive DNA occur?
heterochromatic regions(i.e., telomeres, centromeres)
what type of DNA is found in euchromatin?
moderately repetitive DNA and unique DNA
what are the purposes of moderately repetitive DNA?
length mutability, modulation of transcription factor binding, spacing between promoter elements, cytosine methylation, alternative splicing, mRNA stability, transcription start and termination sites, etc.
what is single copy DNA?
unique DNA; coding DNA; low copy number
what are exons?
“coding sequences,” determines phenotype
what are introns?
“intervening sequences” = areas of genes that generally don’t code for phenotype
is the 5’ region of mRNA that is directly upstream from the initiation codon translated?
no, it is the 5’ UNtranslated region
is the 3’ section of mRNA that immediately follows the translation termination codon translated?
no, it is the 3’ UNtranslated region
what is the dna sequence onto which the transcription machinery bins and initiates transcription?
promotor
what is the highly conserved sequence in DNA serving as the binding site for transcription factor binding?
TATA box
