AP Bio DNA Study Guide

Griffith DNA conclusion

mixed pathogenic and harmless bacterium stands and noticed the living cells became pathogenic, called it transformation, occurs due to assimilation of foreign DNA

Avery, McCarty, MacLeod DNA conclusion

concluded the substance that caused transformation was DNA after discovering only DNA worked in transforming harmless into pathogenic

Hershey, Chase DNA conclusion

concluded that the DNA of a bacteriophage provides its genetic information

Chargaff DNA conclusion

concluded that DNA composition varies from one species to another, and that there’s an equal number of A/T and G/C bases

Watson, Crick DNA conclusion

concluded that DNA is a spiral shape after using the x-ray crystallography pictures made by Wilkins and Franklin

predicts daughter Molecule will have on strand of mother DNA

• supported by Meselson and Stahl

what is a nucleotide made of

nitrogenous base (A, T, C, G), 5-carbon sugar, phosphate group

eukaryotic replication

has hundreds of thousands of origins of replication

prokaryotic replication

only has one origin of replication

antiparallel

DNA polymerase only adds nucleotides to the 3’ strand so it reads 3’ - 5’

• a new strand can only grow 5’ - 3’

replication fork

y-shaped region where new DNA strands grow

helicase

untwists DNA at fork, held apart by single stranded binding protein

topoisomerase

relies strain in the DNA ahead of fork

primase

prodes 5-10 RNA primers

DNA ligase

joins Okazaki fragments

telomere

sequences at the ends of chromosomes that prevent erosion of gene info

• strengthened by telomerase

• smoking/stress in early life can shorten telomeres

where is telomerase found

eukaryotic germ cells that divide often, plays a role in aging + cancer

Okazaki fragments

series of DNA fragments between RNA primers

• lagging strand is synthesized from this

gel electrophoresis

sorts DNA based on length, DNA moves through electrical current, shorter DNA moves faster

polymerase chain reaction

helps scientists by producing millions of DNA copies in two hours