Lecture Oct 23, 2024, (end L.7, start L.8) Flashcards
What is alternative splicing?
Splicing is done at different poitns, depending on the required cell
What are the 100% conserved sequences on an intron
Start= 5’ GU
Branch point= A
End= AG 3’
How does splicing occur?
U1 binds to start of intron,
U2 binds to end of intron
U4/U6 and U5 bind together at branch point
What is actin?
protein for muscle cells
What does the Poly-A tail do?
The final maturation step for pre-mRNA
What signal is used to tell the enzyme where to cut?
What does the poly-A binding protein do?
How does the RNA know when to terminate?
It doesn’t?
Where does the export RNA leave to go to the cutoplasm
nuclear pore complex
What does acellular mean?
Lecture #8
Why are 3 nucleiotides used for 1 a.a?
Because we need to be able to code 20 a.a (why?), and that allows us to do that
Feautures of genetic code
- no commas
- no overlap
- degenrate
- universal
What does ATG code for?
methionine
What is a codon?
One unit of the
nucleotide triplet which
specifies an amino acid
What do the stop codons code for?
none
Names for the 3 kinds of stop codns
amber
Do all stop codons stop the translation?
No, only if they’re within frame
What does ORF stand for? What is it?
Open reading frame. Includes both START and STOP codon within frame
How many different reading frames can a strand have?
6
What is genetic code degeneracy
When one amino acid has multiple nucleiotide codes
Stop codons
TAG, TGA, TAA (all start with a T, switch the G and A, and double A)
What are the color names for the stop codons?
TAG (amber), TGA (ochre), TAA (opal)
How many reading frames are there? How many open reading frames are there
6 different reading frames on a dsDNA, but always only 1 open reading frame
