L 16 Flashcards
(46 cards)
What are some uses of DNA sequencing?
- Research: unjerstand genomes, phylogeny
- Research tool to manipulate DNA: forsensic science
- Medicine: genetic testing, personalized medicine.
What is an essential tool for DNA sequencing? (that’s not normally found in nature)
ddNTPs
What are ddNTPs?
DideoxyNTP.
-synthetic nucleotides that lack 3’-OH
What is the reaction mixture for sanger method?
- Template
- Primer
- dNTPs
- ddNTPs
- Polymerase (taq Pol)
What happens during DNA sequencing if you have too much ddNTP?
Short terminated primers, and not very good coverage over the template
What happens during DNA sequencing if you have a polymerase that makes too much errors?
Errors are incorporated into the product
What does ACV stand for?
Acyclovir, nucleoside analogue
- an antiviral (pro)drug
ACV is a key drug against what?
Against herpes viruses, cytomegalovirus
How is ACV activated in infected cells? What does it mimic?
activated by phosphorylation, making it a dGTP mimic
ACV-TP is an active form, what does it lack and what is it called?
lacks a 3’-OH and is a chain terminator
Why is ACV very effective and has low toxicity?
it’s because it has a much better substrate for viral TK and viral DNA polymerase than for human TK or polymerases
What are sources of DNA sequence errors?
- base misincorporation (dU instead of dT)
- chemical mutagenesis
- ionizing radiation (UV, x rays, cosmic rayrs)
- genetic mutagenesis (retrovirus integration)
- spontaneous lesions (backbone hydrolysis)
What is mutagenesis?
genetic information of an organism is changed in a stable manner
What kind of mutations are there?
- base substitution: transitions and transversions
- insertions and deletions
- breaks in the backbone
What are Darwin’s three ideas that provide an explanation of biological diversity
- variation
- heritable
- differential survival (fitness)
As genomes get larger, what happens with the mutation rate?
It increases and is poorly tolerated as there are more critical parts to higher eukaryotes.
How many bases does the human genome have?
~3billion bases
What percentage of the human genome is repeating?
Fifty
What percentage of the human genome transcribes to RNA
80 percent
What percentage of the human genome encodes proteins?
1.2 percent
RNA is the intermediate in the central dogma, state the process.
DNA–Transcription–> mRNA to which it utilizes tRNA –Translation–>protein
What is the RNA world hypothesis?
- Genetic continuity via RNA replication
- Watson Crick base paring was the key to replication
- Genetically encoded proteins were not catalysts
RNA is catalytic, what could it function as? (two things)
both genome and replicase
RNA is the only currently used macromolecule that is both what?
carrier of genetic info and an enzyme