DNA Flashcards
Name the purines
Adenine & guanine
Name the pyrimidines
Thymine, cytosine & uracil
Name the bases
Adenine, Thymine, Uracil, Guanine & Cytosine
Name the nucleotides in DNA
deoxy ..... Monophosphate (d..MP) adenosine dAMP thymidine dTMP guanosine dGMP cytidine dCMP
Name the nucleotides in RNA
... Monophosphate (..MP) adenosine AMP cytidine CMP guanosine GMP uridine UMP
How do nucleotides linked together?
Phosphodiester bonds between C3 & C5
How are strands held together in DNA?
Hydrogen bonds between bases
How many hydrogen bonds form between the base pair C & G?
3 (higher melting point)
How many hydrogen bonds form between the base pair A & T/U?
2 (melt at lower temp)
What’s a nucleosome?
Histone protein with DNA wrapped around it twice
Where does the primer attach?
3’ (complementary base pairs, if polymerisation occurs from 5’to 3’ then the 5’ end of the new strand is complementary to the 3’ end of the template)
Which enzyme, that is part of DNA replication, assembles nucleotides?
DNA polymerase III
What joins okazaki fragments together?
DNA ligase
What does DNA polymerase I do?
Removes the RNA primer & replaces it using deoxynucleoside triphosphate
What does RNA primase I do?
Adds nucleoside triphosphates on the lagging strand to form an RNA primer
Which new strand of DNA is synthesised in the same
direction as the unzipping?
Leading strand - synthesised continually
What is a lagging strand?
A new strand of DNA that is synthesised in the opposite direction as the unzipping. It is made by joining the Okazaki fragments together.
What unwinds DNA at replication fork & how?
DNA helicase by breaking the H bonds between complementary base pairs