lecture 13 chromosomal abberation Flashcards
griffith’s experiment in a nutshell:
what is the difference between smooth and rough phenotypes
what is the significance of ^
what is the critical result and
what does it mean
what is the overall process that bacteria underwent in the experiment
genetic material can transform in strep
presence of polysaccharide capsule, smooth contains it and rough doesn’t
the capsule allows the bacteria to escape and infect the mouse, but without a capsule, the immune system destroys the bacteria
heat treated S type bacteria and rough bacteria caused the mouse to die, indicating genetic transformation of S genetic info into R cells.
transformation (of virulence)
what did Avery, Macleod, and McCarty show with their experiment
what essentially did they do
what was the critical outcome
DNA is the substance that transforms bacteria
combined type s extracts with type T cells to determine what component was transferring. They distinguished this by adding RNA, DNA, and protein enzymes.
the mix with DNAase did not transform the R cells.
what question was Hershey and chase trying to answer
what is found in DNA but not proteins
what is found in proteins and not DNA
how did they do this experiment
what did they find
what does this show
what kind of material enters a cell during infection via phage
phosphorus
sulfer
they separated phage coats from bacterial cells
most of the phosphorus had entered the cell and the sulfur stayed outside of the cell
genetic material (what infects) is DNA, not proteins (which is what the coat the attaches to the cell is made of)
griffith:
mccaferty:
Hershey:
transformation occurs (with smooth and rough)
bacteria is what causes this transformation of virulence (from bacteria to bacteria) (with enzymes that delete one of the components)
DNA infects with phages, not the outer protein coats (with phosphorus and sulfur)
4 characteristics that genetic material must exhibit
replicare
store info
express info
variation via mutation
chargoff rules
A = T (&U)
C = G
purines:
pyrimadines:
adenine
guanine
uracil
thymine
cytosine
nucleoside vs nucleotide
nucleoside is missing the phosphate group
bonds that link nucleotides
between where
phosphodiester
C-5 and OH group on C3
DNA structure:
type of double helix
diameter
nm per tuen
bp per turn
nm per base
parallel or antiparallel
types of grooves
right handed
2
3.4
20
.34
antiparallel
major and minor
major distinctions between A, B, and Z DNA
right handed and compact
biologically significant
left handed double helix
central dogma
dna
transcription
rna (with help of ribosome)
translation
protein
when would RNA be double stranded
secondary structures
some viruses
functions -
mRNA
rRNA
tRNA
template for protein synthesis
ribosomal component
carry amino acids for protein synthesis
How do we know that RNA is genetic material
degrade proteins from RNA in a virus and make a hybrid with them
the type of infection is related to the type of RNA present, not the coat proteins
important distinction: the RNA makes new coat proteins that match it (OG)
what is dependent on replication of viral RNA
how does retrosynthesis occur
what enzyme is responsible for this
RNA becomes the template for DNA synthesis, which is then incorporated into the host genome
RNA dependent DNA polymerase reverse transcriptase
what happens when you denature and renature DNA
the RNA transcript that is complementary ends up forming a DNA/RNA hybrid with the strand that it came from
hyper chromic shift:
where do nucleic acids absorb most light
what is the shift during DNA denaturation used to determine
what has a high absorbancy at the aforementioned wavelength
what - rich DNA has a lower melting temperature
260 nm
melting temperature
single stranded
A-T rich DNA
