First online MC assessment oct 9 to 11th
10-15 questions from lecture 2 through 8
2% of final grade
2 attempts anytime over 3 days
What is your DNA sequence doing?
Scientists defined functional as something that might be expressed
DNA is still junk because it makes stuff like transposons and viruses doesn't make you
junk DNA is evidence of evolution
relating DNA and chromosomes
what do you do with the ends of the chromosome?
Double helical structure of DNA with 2 antiparallel backbones
o held together by hydrogen bond
Antiparallel means each of the single strands of DNA has a distinct 3' and 5' end that confers polarity
on DNA backbones
one end have a 3' the other strand is 5'
3' end has a free hydroxyl (OH) group
5' end has a free phosphate
2 strands of double helix run antiparallel to each other
Replication is semi-conservative
demonstrated by Meselson-Stahl expperiment
DNA polymerase extends the 3' OH
DNA replicates from 5' to 3'
Elongation happens at the 3' end
to replace the gap shown below, DNA will be synthesized but in which
left to right extend the 3' end
to replace the gap shown below DNA will be synthesized but in which
right to left
extend the 3' end
to extend the chromosome as shown below, DNA will be synthesized
but on which strand?
extend the 3' end, find and identify 3' and it'll extend from there,
length in the question doesn't matter
Replisomes replicate one strand continuously, one discontinuously, active at a replication fork
Replisomes contain 2 molecules of DNA polymerases
going simultaneously, only can extend the 3' end and the parent strands
are going in the opposite directions
replication is semi-conservative and semi-discontinuous
Replication "bubble" arises from 2 "forks" created at 1 "origin"
both direction at the same time
creates a replication bubble
be able to draw the structure of the bubble
Just 2 forks makes 1 bubble (draw a bubble)
Primers provide a 3' OH so that DNA polymerase can extend
prokaryotes' genome are small, it can have one origin
Large, linear, eukaryotic chromosomes fire several origins simultaneously
going both directions and multiple origins so it replicates them quickly
Chromatids are identical DNA molecules attached at their centromeres
G1: growth phase, DNA stays the same
S phase chromosomes repli