Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
27 Cards in this Set
- Front
- Back
|
Which chromatin replicates first in S phase, heterochromatin or euchromatin?
|
Euchromatin (less condensed) replicates before heterochromatin (highly condensed)
|
|
|
Two types of chromatin?
|
Heterochromatin & Euchromatin
|
|
|
What is the difference between topoisomerase and helicase?
|
Topoisomerase-unwinds helix
Helicase-unzips two strands |
|
|
What direction is DNA synthesized?
|
In the 5'-->3' direcion
|
|
|
What are the differences between Topoisomerase 1 and Topoisomerase 2
|
Topo1-->Relieves stress in DNA helix
Topo2-->Untangles DNA by pulling them apart and stitching them back together. |
|
|
What direction is DNA read by DNA polymersase?
|
3'-->5'
|
|
|
What is a common use for topoisomerase inhibiting drugs?
|
Cancer treatment.
|
|
|
What are telomeres?
|
End tails on chromosomes
|
|
|
What does telomerase do?
|
RNA protein complex,
Reverse transcriptase template used to add a repeating AA sequence and maintain telomere length. |
|
|
What do telomeric repeat sequences do?
|
Allow DNA repair mechanisms to recognize the chromosome end as normal and prevent inappropriate 'stitching' of chromosomes together.
|
|
|
How is telomerase affected by age?
|
Telomerase activity slows as you age.
|
|
|
How does cancer affect telomerase
|
Telomerase is highly expressed, rendering the cancer cells immortal
|
|
|
What is the difference b/t the DNA coding and DNA template strands?
|
Coding strand represents the mRNA strand, template is used for transcription
|
|
|
DNA coding strand is read:
|
5'-->3'
|
|
|
DNA template strand is read
|
3'-->5'
|
|
|
mRNA is read:
|
5'-->3'
|
|
|
Synthesis always occurs in which direction?
|
5'-->3'
|
|
|
What molecule transcribes DNA?
|
RNA Polymerase
|
|
|
What does the RNA polymerase "rudder" do?
|
Seperates the template DNA from the newly synthesized RNA
|
|
|
How does RNA polymerase know which direction to go down the DNA strand (ie. which strand is the template strand?)
|
It finds the promoter region
|
|
|
How does sigma factor work in prokaryotes?
|
Binds the core RNA polymerase enzyme and directs its binding to specific promoters
|
|
|
How do RNA polymerases recoginze the start points?
|
promoter regions-cis DNA sequences
TATA boxes-element within the promoter region that signals the start point |
|
|
What is the first post-transcriptional modification to the RNA?
|
the 5' end is capped (as the rest of the strand is being transcribed)
|
|
|
What are 2 functions of the 5' RNA cap?
|
1. protection of the strand
2. signalling to mitos |
|
|
What are the first 3 modifications to the RNA molecule?
|
1. cap
2. poly A tail 3. splicing to remove introns |
|
|
Do introns have a purpose?
|
Yes. Gene regulation, miroRNAs, other unknown functions.
|
|
|
What molecule regulates splicing of RNA?
|
spliceosome. it's a ribonucloprotein
|
