Nov 8 Flashcards
mRNA vs rRNA roles?
m is for info flow, r is structural and synthesis role
Does RNA have more or less functions and flexibility than DNA?
More flexibility and roles, it can fold complex
Why does RNA but not DNA have catalytic function?
RNA has the 2- OH group, it can act as electron donor and acceptor
Do exonucleases attack RNA vs DNA?
Can attack RNA, not really DNA as it is double stranded
Is RNA more or less stable as alkaline condition?
It is more basic environment, so the 2’OH would be more likely to deprotonate and make RNA less stable
Why does DNA have thymine and RNA has U ? Why not the other way around?
Thymine and Uracil so RNA and DNA strands can be distinguished from one another in the cell. Thymine is like uracil but with a methyl group that stabilizes it, so it is is present in DNA to stabilize DNA as it needs to stick around longer than RNA in the cell
What is the precursor DNA base for uracil?
It is more efficient to deaminate cytosine than demthylate thymine, uracil is cheaper version of thymine in terms of energy
How many strands is tRNA?
It is 1 RNA strand that is folds into a clover leaf
WHen RNA folds into double helix, it is similar to what form of DNA?
A form
When RNA folds on itself, what 3 local regions of dsRNA show up?
Get bulge from 1 nucleotide not matching, then internal loop of many nuclotides not matching, then hairpin.
Why is the tetraloop structure stable? How many nuclotides?
It is 1 big loop with 6 nuclotides. It has H bonding between bases, both watson crick and non canonical base pairs.
It has base pairing with the PO4 backbone, and also has base stacking
What are pseudoknot RNA structures?
It is when stem-hairpin has the nuclotides of the loop part base pair with other bases on the strand, then, this strand can thread through the loop
What prevents dsRNA from looking like B form DNA?
It is the 2’OH groups, that is why it resembles A form instead.
How are major and minor grooves different for dsRNA (like A form DNA) vs B form of DNA?
The major grooves are narrower and deeper than B form, so amino acids can’t really fit into dsRNA major groove. Minor grooves are wider and more shallow than B form, and proteins can bind there instead.
How does thermosensor for virulence gene expression work?
You have dsRNA stem loop with a ribosome binding site in the stem. When temp increases , the stem melts a bit and ribosome can get to its binding site. THis then allows it to express a gene as secondary RNA structure changes
