Theme 1 module 4 Flashcards
Where is the majority of DNA located in prokaroyetes cells?
nucleoid
What is small circular DNA molecules called in Prokaryoetes?
plasmids
mitochondria contain their own, smaller _______
chromosomes
Streptococcal bacteria
are normal inhabitants of
the human upper respiratory tract
Benign strains
are harmless and not associated with any
disease symptoms
Virulent strains
associated with mild symptoms, such as the
sore throat resulting from Strep throat or as the
severe symptoms resulting from pneumonia
What did Fred Neufeld do? which is also called Griffith’s Experiment
made a number of
observations in the 1920’s. There are two strains
of the bacteria, Streptococcus pneumoniae. One
strain, when injected into the mouse caused
death. The other strain when injected into the
mouse had no effect. The R strain is a harmless
or benign member of the microbiome, in this
case, the mouse microbiome. The S strain is a
virulent form of the same bacteria. The question
is, can information that determines the nature of
the strain, whether benign or virulent, be
transferred from one bacterial cell to another?
Griffith heated the virulent bacteria to high temperatures in order to _____
kill them
What was griffth hypothesized?
that the information that
makes a cell virulent was still present, but that the
cell carrying that information had been killed.
Could that information still be used
What griffth conclude that happed?
Transfomartion,
Transformation is a change in cell behaviour
resulting from the incorporation of hereditary
material from outside of the cell.
What was Oswald Avery question at beagining of expirment?
Which macromolecule in the
bacterial cell was holding all that important
information that could cause transformation.
Which molecule was carrying the hereditary
What were 5 macromolecules in the cell that was considred in Avery expriments?
Lipids, carbohydrates,
protein, RNA, DNA. Lipids and carbohydrates
were discounted. That left proteins, RNA, and
DNA. Avery and his colleagues selectively
eliminated each type of macromolecule from the
cell extracts and then tested the remaining
molecules for their ability to induce
transformation
What is the enzyme that degrade RNA, DNA and Protein?
RNase is an enzyme that specifically degrades
RNA molecules; DNase degrades DNA
molecules; protease degrades proteins
What avery observed?
researchers discovered was that in
the absence of protein or RNA, but in the
presence of DNA, there was still transformation.
In contrast, extracts treated with the enzyme that
destroys DNA were unable to transform the
benign bacterial cells. In the absence of DNA,
there was no transformation. They concluded
from these experiments that the macromolecule
that determines the characteristics of the cell was
carried in the DNA molecules of the cell
What did Rosalind Franklin discovered, and what techniques she used?
Franklin used a technique called x-ray
diffraction to aim x-rays at DNA to create images
based on the diffraction of the x-rays by the
atoms in the DNA molecule. This famous photo
51 was key to the discovery of the theoretical
structure of DNA. It was from this single image
that the helical nature of DNA was identified, and
from which calculations were made to determine
the dimensions of the molecule
