Reverse Transcription, Protein Metabolism I 28 done Flashcards
What is reverse transcriptase?
An enzyme of a retrovirus. These viruses contain RNA genetic material that can be sued to synthesis DNA incorporate that DNA into host cell.
What is integrase?
It is the enzyme thta integrates the newly synthesized DNA from RNA into the host’s chromosomes. This is done simiilarly to transposon insertion
What are oncogenes?
retroviruses that can drive cancer
Name a virus capable of causing cancer and the enzyme responsible for it.
Rous Sarcoma Virus. Enzyme: SRC kinase
Why is it difficult to treat HIV with a vaccine
HIV is a retrovirus whose reverse transcriptase enzyme is prone to many error, resulting in rapid mutation of its envelope
How do we treat HIV currently?
cocktail of many drugs:
- truvada, which is a 2 drug cocktail
- descovy whihc is a 3 drug cocktail
What was the importance of AZT in medicine?
It was used to treat HIV, although it was more because it wasn’t specific and attack the patients cell, it should that HIV was a retrovirus, because AZT is a reverse transcriptase inhibitor
What is the role of telomerase? What is its mechanism?
It is a reverse transcriptase enzyme. It uses Rna as a templete to extend the telomeres (ends of chromosomes). This helps stop the lagging strand problem (shortening of Dna until nothing left) caused by DNA replication
Where does protein synthesis occur?
On the ribosome, attached to endoplasmic reticulum
Describe the genetic code of proteins
The genetic code is non-over lapping, meaning the codes are indepenent of each other, unlike overlapping codes.
The code consists of triplet nucleotides, called codons.
What direction is the genetic code written in?
5’ to 3’ direction
Which codon of the genetic code determines the reading code?
The first base. If the reading frame is different even by one base, this changes all other codon orders. Can be cahanged through insertions or deletions
How many reading frames are there in mRNA?
Only 3 potential reading frames
What are the termination codons of protein synthesis?
They tell the protein to stop. They are UAA, UGA, UAG
What are the initiation codons of protein synthesis?
Just AUG or MET codon
WHat is codon bias?
The tendency for cells to have a oreference for a certain codon.
WHich Amino acids only have one codon?
Met (initiation) and Trp
How does tRNA work with mRNA?
The codon in mRNA base pairs with the anticodon in tRNA through hydrogen binding. When these two RNA segements align, they are anti parallel
How does anticodon of tRNA know which base pairs to hydrogen bond with?
They use the WObble base
WHen the anticodon hase a C at 5’ in will h-bond with..
G of codon at 3’ end
WHen the anticodon has a A at 5’ in will h-bond with..
U condon at 3’ end
WHen the anticodon has a U at 5’ in will h-bond with..
with A or G at codon 3’
WHen the anticodon has a G at 5’ in will h-bond with..
with C or U
WHen the anticodon has a I at 5’ in will h-bond with..
A, U C
