Module 5 1-4 Flashcards
early analysis of composition of genes was done by ____ in ___
Friedrich Miescher;1869
Friedrich Miescher examined
Extracts from nuclei of human white blood cells
when friedrich examined Extracts from nuclei of human white blood cells he found that they were
weakly, and contained phosphurus
what did friedrich call what he examined
nuclein
after chemical analysis it was found that nuclein was
DNA
DNA was determiend to have 3 features which are
phosphate group, nitrogenous base, and a ribose sugar that lacks hydroxygroup
a ribose sugar that lacks hydroxygroup is called
deoxy
in nucleic acids the Backbone is made up of
chain of alternating
phosphate and sugar
Nucleotide is made up of
sugar+phosphate group+nitrogenous base
how many different nucleotides are in
DNA
four
how many different building blocks are there
4
how many different nitrogenous bases are there
4
RNA is ______ sugar
ribose
DNA is _______ sugar
deoxyribose
DNA has what nucleotide that RNA doesnt
Thymine
What Nucleotide does RNA have that DNA doesnt
Uracil
RNA is usually _______ stranded
single
DNA is usually _____ stranded
double
In the early 20th century, the prevailing assumption was that
genes were made of ___
proteins
why did people think genes were made of proteins?
proteins have 20 building blocks and dna only has 4. which means more potential variation.
More protein by weight in chromosome then DNA.
When was the Frederick Griffith Experiment
1928
what is Streptococcus pneumoniae known for
its bacteria that frederick griffith experimented on
what did frederick griffith experiment on
streptococcus pneumoniae
Streptococcus pneumoniae is the most common cause of
pneumonia
Frederick Experiments help determine that DNA is a
genetic material
what 2 variety of streptococcus pneumoniae did frederick griffith observe
smooth strain and rough strain
describe smooth strain of streptococcus pneumoniae
polyssacharide capsule, virulence
virulence
harmful
what does polyssacharide capsule in smooth strain of streptococcus help do
avoid hostile immune system.
describe rough strain of streptococcus pneumoniae
no capsule, not virulent
why doesnt rough strain of SP have a capsule
because mutation in an enzyme makes capsule.
why isnt rough strain of SP virulent
because it lacks a polysaccharide capsule, which is the key virulence factor that protects the bacteria from the host immune system
frederick injected what animal with SP
mouse
mouse infected with Smooth SP would
die
mouse infected with rough SP would
live
when he heat treated smooth SP the mouse
lived
mouse with heat treated smooth SP and Rough SP would
die
when isolated bacteria from blood of dead mice after heat streated smooth and rough sp what did he find
Smooth strain of SP
frederick thought that the R strain transofmred into the S bacteria
S strain
frederick thoguht that after mixing R bacteria with heat-killed
S bacteria
the takeaways from frederick griffiths experiment was that the transformation was most likely
genetic
why did they think genetics was Dna based after frederick griffith experiment
proteins denature irreversibly in heat
proteins denaturing in heta is called
transformation
transformation also takes place in
vitro
who performed the mccarty experiment
Avery, MacLeod
purpose of McCarty Experiment
Characterize the “transforming principle” from the
Frederick Griffith experiment
summary of frederick griffith experimemnt oddity
dead d strain and r strain mixed and with time made living s strain
describe mccarty experiment
treated combination of smooth Dead S strain and R strain with Protease, dnase, rnase, and ultracentifiguration
when combination was treated with protease was their transformation
yea, S strain remained
when combination was treated with rnase was their transformation
yes,S strain remained
when combination was treated with dnase was their transformation
no, stayed R strain
when combination was treated with ultracentrifiguration was their transformation
yea, S strain remained
what does Dnase, Rnase, ultraCentrifiguration, and protease do.
protease- protein destroyed
Dnase- dna eliminated
Rnase- rna destroyed
Ultracentrifiguration- fats eliminated
since the Dnase experiment was tehe only one to keep R strain it meant that
there is a predominance it DNA
what year was the hershey and chase blender experiment
1952
what was the final result from hershey chase experiment
Final evidence that DNA is genetic materia
describe hershey and chase blender experiment
Two separate cultures of bacteria were infected with T2
* One culture contained medium with radioactive phosphate (32P)
* The other culture contained medium with radioactive sulfur (35S)
- They used “aliquots” of each culture to infect fresh bacteria cultures
- Using a blender, they separated the T2 protein coats attached to
bacteria from the bacteria
Centrifuged the solution
what happened in hershey and chase blender experiment
They followed the life cycle of a virus (bacteriophage) that
infects bacteria
what does Centrifuged the solution do
Heavier bacterial cells migrated to the bottom, and Lighter protein coats stayed in the supernatant
sulfar is incorporated in
proteins
phosphurus is incorporated in
nucleic acids
this experiment should have helped hersy and xhase track where
proteins and nucelic acids were
A ________ is a liquid or medium which remains above a pellet after ______ and is composed of lighter or smaller materials.
supernatent;centrifuation
denser particles migrate toward the bottom of the tube to eventually form a
pellet
what amino acids contain sulfur
cysteine and methionine
in T2 phage DNA enters
bacterial cell
DNA causes bacterial cell to make more
bacteriaphage
how many steps is lifecycle of bacteriaphage
5
what is the lifecycle of T2 bacteriaphage
phage attaches to bacteria
phage injects Genes into host cell
Phage DNA Replicates
Phage particles assemble
cells bursts releasing new phage
when p32 was used radiactivity was in bacterial hopst and not bacterialphage floating in supernatant
s35 was not contained in bacterial cell, which will now start making bacterial phae, it was in bacteriaphage coats.
DNA is ______
Universal
how many domains of life are there
3
the three domains of life use DNA for
store genetic
information
viruses use ____ or ____
DNA;RNA
hershy and chase blender experiment S35 life cycle
t2 phage-> infect e-coli and grow in s35 containing medium -> phages become infected with s35 DNA->introduce phages into bacterial culture->(blend breifly)->radioactivity recovered in host and passed on t phage progemy
hershy and chase blender experiment P32 life cycle
t2 phage-> infect e-coli and grow in P32 containing medium -> phages become infected with p32 DNA->introduce phages into bacterial culture->(blend breifly)->radioactivity recovered in ghost phage ghosts
in cambridge england in the 1950s researchers were racing to
elucidate the molecular structure of DNA
in the 1950s scientists knew
DNA consists of nucleotides, chargaffs rule, DNA can create a regular x-ray diffraction pattern
chargaffs rule developed by
erwin chargaff
chargaffs rule was
all dna there was the same amount of adenine and thymine, and cytosine and guamine
since DNA can create a regular x-ray diffraction pattern it suggested
DNA must have a regular structure
in chargaffs ratios you can see
there are almost an equal percent of A and T, and almost equal C and G
who found x-ray Crystallography of DNA
rosalind frankline, and maurice wilkens
X ray differaction pattern can be seen in ______ taken by rosalind frankin
photo 51
what 2 man put information from rosalind frankling Crystallography toether
james watson and francis crick
james watson and francis crick made a
DNA model out of metal parts and pieces. it was double helix
double helix looks like a
ladder with twist
Adenine and thymine are bound by
2 hydrogen bonds
cytosine and guamine are bound by
3 hydrogen bonds
describe double helix
outside is sugar and phosphate, and facing inward is bases connected by hydrogen.
always _____ and ______ being paired up
purine and pyrimidine
how many bases are across inside of double helix
3
how many starnds of dna wrap around each other
2
1 full turn of dna doublex helix is how many base pairs
10 base pairs
Base pairing is _____
complementary
the 2 strands in dna double helix bind ___
anti-parallel
antiparallel means
When two strands bind to form a double
helix the 5’ end of one strand faces the 3’
end of the other strand and vice versa=ANTIPARALLEL
Dna has a “________”
direction
the two free ends of dna strands are
different
One end has a of DNA strand has
a phosphate bound to the
fifth carbon atom of the sugar ring (5 prime)
The other has end of DNA strand has
a third carbon
(hydroxy-group bound)
= 3’ (three prime)
the strand with a third carbon is known as a
Free strand
Watson and crick published their paper in what journal and when
nature; 1953
double helixes come in different forms
B DNA, and Z DNA
B DNA is
right handed
Z DNA is
left handed
What type of DNA is most often found in nature
B DNA (right handed dna)
