W2 Chromatin + Chromosomes Flashcards
why do some areas of DNA need to be packed more/less
- to control gene expression
- more packed = polymerase cant bind for transcription
what does an area of dense transposons mean
- less transposon movement
where are regions of gene expression found
euchromatin regions
why does histones have more Lysine and Arginine AA
more +ve to bind to negative DNA
what’s good about gene duping
prevents mutations from affecting genes
how do mobile DNA elements move
by the enzyme = transposase
what is an outcome of transposition
can cause mutations
how does the insertion of a transposon affect genes
- disrupt regulatory sequence
- start mutations at break sites
what type of RNA strand type retroviruses exist as
as ssRNA
how do retroviruses like HIV integrate into host cell
conversion of viral RNA to dsDNA
what are retrotransposons
- mobile elements that cant move themselves
- don’t have protein coat
what are 2 examples of non-retroviral retrotransposons
LINEs + SINEs
how much of genome is made of non-retroviral retrotransposons
30%
what are the 3 things junk DNA normally known as
- regulatory elements
- regulatory RNAs
- ancestral genes
what are introns and their function
- non coding regions within genes
- gene expression regulation
where are introns found
in-between exons
when do introns get removed
before translation
which elements are upstream
promoters
enhancers (distal)
which elements are downstream
downstream enhancers
how is the genome actually arranged
3D model
what are class 1 transposons
retrotransposons
what are class 2 transposons
DNA transposons
what are DNA transposons able to do
encode their own transposase
what do transposase do
move mobile elements of the DNA
what can be found on the sequence of a retrotransposon
reverse transcriptase
is retrotransposon found as DNA or RNA
DNA
what is the process of cut and paste replication
- inverted terminals repeats mark breaksites
- transposase cuts IRs
- insert into genome
when can transposon duplication occur
during S phase
how can transposons drive evolution (4 ways)
- gene dupes
- gene loss
- regulator functions
- move non coding region to start coding
how many AA monomers for proteins are there
20
what is a transforming factor
molecules which can transfer genetic information
what is transforming principle made of
carbon
nitrogen
hydrogen
phosphorous
if transforming principle is DNA then what is it not
RNA or protein
how was transforming principle proved
chase and hershey experiment
