Bootcamp Chapter 6 Flashcards
(53 cards)
There is no _____ hydroxyl group on DNA
a) 3’
b) 1’
c) 5’
d) 2’
D
DNA wraps around proteins called _____. This DNA complex is referred to as ______.
histones, nucleosome
Each nucleosome contains _____ histone proteins
a) 6
b) 7
c) 8
d) 9
D
Which histone is responsible for keeping the DNA wrapped around the central histone core?
H1
T/F? Histones are found in both eukaryotes and prokaryotes.
FALSE - not found in bacteria!
Describe how the histones and DNA are able to tightly bind together.
Histones are positively charged while the DNA is negatively charged from the phosphate groups
What chemical process will create for a more loosely packed DNA strand and thus increase transcription levels?
Acetylation
What histone modification processes will decrease transcription?
methylation and deacetylation
Methylation and deacetylation both decrease transcription rates. Differentiate between the two.
deacetylation - condenses DNA
methylation - hides the transcribing DNA
Bacteria have ____ origin of replication, while eukaryotes can have _____
one, several
What is attached at the 5’ and 3’ ends of DNA?
5’ = phosphate
3’ = hydroxyl group
Origins of replication will be found more in (AT/GC) rich segments if DNA because it has fewer bonds and is thus easier to pull apart
AT
DNA Gyrase
DNA gyrase is a subtype of DNA topoisomerase found in bacteria and plants
What relieves tension ahed of the replication fork as helices is “unzipping” the DNA strand?
topoisomerase
Because DNA polymerase can only extend in the 3’ direction of an existing strand, _____ will place a ____ primer at the origin of replication.
DNA polymerase will now have a ______ _____ group to attach free ______ ______.
primase, RNA
3’ hydroxyl, nucleoside triphosphate
DNA polymerase can extend and read in what direction?
extend - 5’ to 3’
read - 3’ to 5’
What signals for termination of DNA replication?
when two replication forks meet or when proteins bind (physically stops replication fork)
T/F? Because DNA polymerase needs an RNA primer in order to extend DNA - a little piece of it is not replicated. These are called telomeres.
TRUE
During initiation of translation, RNA polymerase will travel along the _____ in what direction?
a) noncoding, 3’ to 5’
b) sense strand, 3’ to 5’
c) noncoding 3’ to 5’
d) antisense 5’ to 3’
C
Where does transcription occur in prokaryotes?
How many elements are found in prokaryotic promoters?
cytosol
-10 to -35
What will prokaryotic core RNA polymerase combine with to form the RNA polymerase holoenzyme? What is the holoenzyme’s function?
sigma factor - when the RNA polymerase and sigma factor are bound, this enables it to target promoter sites
Rho-Independent Termination
termination that relies on a sequence of DNA which will cause the RNA transcript to fold into a hairpin loop.
This structure will cause the polymerase to pause and be released.
Rho-Dependent Termination
Rho will move along the RNA transcript in the 5’ to 3’ direction and catch up to polymerase. Once it touches RNA polymerase it will cause displacement and termination
Operon
Function?
when a group of related genes are under the control of one promoter site
ensures that the cell conserves its resources
