Biochemistry year 1 Flashcards
What does DNA do
Acts as repository of genetic information, directing own replication and directing transcription onto complimentary RNA
What does mRNA do?
Directs translation of genetic info into proteins
What does tRNA do?
Delivers amino acids during protein synthesis
What does rRNA do?
Structural and fucntional roles in ribosomes
What are the purine bases, and what are the pyramidine bases?
Purines are Adenine and Guanine, pyramidine bases are Cytosine and Thymine/Uracil
What is the difference between a nucleotide and nucleoside?
Nucleosides are bases and a 5-carbon sugar, nucleotides are phosphorylated.
Recall the 5’->3’ structure
the Carbon 5’ is at the top, 3’ is at the bottom of the molecule
What base pairs have 2 hydrogen bonds and which have 3
A-T: 2
G-C;3
What unzips DNA at the start of replication?
DNA Helicase
Which is the leading/lagging strand?
With the parental strand above, the leading strand is to the left with the 3’ strand.
What enzyme encourages RNA primers to bond to the strands?
DNA primase
What does DNA polymerase do?
Matches and adds new nucleotides to form daughter DNA strands
what does DNA ligase do?
Joins fragments of Okazaki fragments on the lagging strand
Why do Okazaki fragments form?
Helicase opens DNA from 3’ to 5’. Lagging strand goes other way. Short fragments join.
How do antiretroviral chemotherapeutic agents work?
They become incorporated into viral genome, block DNA synthesis
