Download 2 - Griffith-Avery-McLeod-McCarty SBI4U – Molecular Genetics Date

SBI4U – Molecular Genetics
234831062
Date: ___________________________
Griffith, Avery, MacLeod, McCarty
Background
Chromosomes of eukaryotes contain a variety of _________________ in addition to
________________
Question arose as to whether the nucleic acids (DNA) or proteins, or both together,
are the ________________________________________
Until the early _______________, most biologists were inclined to believe that the
_________________ were the chief carriers of heredity
Nucleic acids contain only ________ different building blocks, but proteins are made
up of ____________ different amino acids
Proteins therefore appeared to have a greater ________________ of structure, and
the _______________________________ seemed first likely to rest on the
________________ of the proteins
Page 1 of 3
SBI4U – Molecular Genetics
234831062
Frederick Griffith
English Army Doctor
Wanted to make a ____________ against a bacteria named ___________________
____________________, which caused a type of pneumonia
Since the time of Pasteur, about 50 years
before, vaccines had been made using
________________________________
which could be injected into patients to
elicit the _________________________ of
live cells without risk of _____________
Though he failed in making the vaccine he stumbled on a demonstration of the
_____________________________________ by a process we now call the
“______________________"
He found that the bacterium had two forms when grown on agar plates, a ________
(S) and a __________ (R) form
The R bacteria were harmless, but the S bacteria were lethal when injected into
mice
However, surprisingly when live ____ cells were mixed with killed ____ cells and
injected into mice the mice died, and the bacteria recovered from the mice had been
“_____________________________" into the S type
This experiment strongly implied
that ____________________
had been transferred from the
__________________________
It was hard to know exactly what
genetic material was transferred
and was responsible for the
__________________________
Page 2 of 3
SBI4U – Molecular Genetics
234831062
Avery, MacLeod, McCarty
In 1944, the team of Avery, MacLeod and McCarty revisited this experiment and
attempted a more definitive experiment
They extracted from ____ bacteria nuclei __________________, proteins and other
materials and mixed R bacteria with these different materials, and only those mixed
with _______ were transformed into ____ bacteria
This experiment strongly implied that ________ is the “_____________________
______________” and not _______________ or other materials and by this was
demonstrated what is known to us as the transforming principle - that ____________
are made of DNA
Page 3 of 3