chapter 16: the molecular basis of inheritance

the structure of DNA formed by double strands

repair enzymes fixing errors in base-pairing

enzyme that degrades nucleic acids

• involved taking a pathogenic strain of DNA and seeing how it affected non-pathogenic DNA strands. It showed the pathogenic strands would turn the harmless ones into pathogenic

• proved that something can cause DNA to change

• proved DNA is material used in transformation

• shows DNA is what caused harmless strains becoming pathogenic

virus that infects bacteria

• labeled the protein and DNA of a bacteriophage radioactively in separate tests. later bleneded the phage and bacteria to separate into protein layer and “organic pellet”

• when protein was labeled, radiation would be in protein layer. when DNA labeled, it was in the “organic pellet” meaning that is what transferred into the bacteria

• proved DNA is genetic material

[A] = [T]

[C] = [G]

took a picture of DNA structure using DNA crystallography and proved it was a double helix

discovered DNA ran antiparallel and it consists of purine bonded to a pyrimidine

• conservative: of the 2 daughter cells, one gets the original strand and the other gets brand-new strand

• semi-conservative: the original DNA strand is copied in a way that each daughter cells gets 1 new strand and 1 original strand

• dispersive: different sections of DNA is received by daughter cells, part of each strand being new and old.

• used different isotopes of nitrogen, which all are different weights, to label the original strand of DNA and new strands in a way to make them separate

• proved that after several generations, the DNA replicated in a way that the semi-conservative model is correct model

“bubble” in DNA strand where replication is occurring

it breaks the double-helix to allow for the replication fork to open

support the separated single-DNA strands until they can be copied

initial sequence of RNA nucleotides used to initiate DNA replication

places down the primer because it can start a RNA strand from scratch

extend the primer and replaces primer RNA nucleotides with DNA ones

• leading strand can be done continuously because it is in the direction of the fork

• lagging strand is done in discontinuous fragments because it is being synthesized away from fork opening

unconnected DNA fragments of lagging strand

used to stitch together Okazaki fragments

it slowly gets shorter and shorter because when the primer gets removed, there is no 5’ end for the polymerase to add onto

repeating segments of nucleotides at end of chromosomes to prevent them from getting too short too fast

• lengthens the telomeres in germ cells

• found in somatic cancer cells because it lets them be capable of unlimited division