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Biology 224 > Chapter 11, Nucleic Acid Structure and DNA > Flashcards

Chapter 11, Nucleic Acid Structure and DNA Flashcards

(62 cards)

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1
Q

Genetic material needs to…..(4)

A
  • contain information to build and run an entire organism
  • be copied accurately
  • be transmitted, passed from parent to offspring (cell to cell)
  • Account for the known variation within and between species
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2
Q

_________________ determined what Genetic Material was

A

a series of experiments

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3
Q

Most scientists believed…

A

genetic material was proteins since they were known to be much more variable than nucleic acids

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4
Q

There are _____ amino acids and ____ nucleotides

A

20, 4

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5
Q

________ set stage for showing what genetic material would be in …

A

Griffith, 1928

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6
Q

Griffith worked with….

A

two strains of bacteria Streptococcus pneumoniae

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7
Q

The ______ strain was _______ and jilled mice with a pneumonia infection

A

S (smooth) virulent

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8
Q

The ____ strain was _____ and the mouses immune system would kill it

A

R (rough) not virulent

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9
Q

Griffith performed ____ experiments

A

four

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10
Q

Griffith’s first experiment…

A
  • injected mice with S strain and saw that mice died
  • after death, living S bacteria were found in the blood
  • this established virulence of S strain

control: injected living type S bacteria into mouse

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11
Q

Griffith’s second experiment…

A
  • injected mice with R strain and saw that mice did not die
  • dead bacteria were found in the blood
  • established non-virulence of R strain

Control: injected living type R bacteria into mouse

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12
Q

Griffith’s third experiment…

A
  • heat killed the virulent S strain and injected the dead S strain
  • mice did not die
  • bacteria was killed and found inside blood

Control: Injected heat-killed type S bacteria into mouse

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13
Q

Griffith’s fourth experiment…

A
  • he then mixed the live R strain (harmless) with the heat killed S strain (harmless) and injected it into mouse
  • Mice did, living S strain was recovered

Control: Injected living R and heat killed S into mouse

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14
Q

Whatever agent that had transformed R into S…

A

must be the genetic material

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15
Q

This transforming material is called…

A

transforming factor

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16
Q

__________ did more detailed experiment in _____

A

Oswald Avery et al., 1944

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17
Q

Published results in

A

1944

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18
Q

They performed the same part of the fourth experiment which is…

A

took live R and mixed with heat killed S

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19
Q

Difference in experiment is they…

A

first treated it with enzymes to destroy some class (or another) of organic molecules

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20
Q

Treated heat killed S strain with _______ to destroy proteins

A

proteases

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21
Q

When they injected heat killed S with proteases to destroy proteins and then added these to live R proteins …

A
  • the mice still died
  • if genes in the heat killed S strain were proteins, they should have been destroyed and not able to transform the live R into the S strain
  • therefore GENES (PROTEINS) were NOT genetic material
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22
Q

Treated heat killed S with _____ to destroy nucleic acids

A

nucleases

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23
Q

When they treated heat-killed S with nucleases to destroy nucleic acids and added this to live R strain

A
  • the mice lived
  • genes must consist of nucleic acids since when they are destroyed, so it ability to transform the R strain to the lethal S strain
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24
Q

This was…

A

first demonstration that genes were nucleic acids

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25
Doubts about experiment were..
- doubts about purity of samples - or weather small amounts of contaminating molecules could have been altering the results
26
So people were..
still skeptical
27
Second demonstration on nature of genes was done by __________ in ______
Hershey and Chase (1952)
28
Hershey and Chase used...
radioactive isotopes in viruses
29
Of all organic molecules only _____ have _____
proteins have sulfur
30
So if you grow viruses in radioactive (35)S...
only proteins will be "labeled"
31
Used viruses because
viruses were trusted, studied
32
Only _____ _____ have _________
nucleic acids, phosphorus
33
Viruses grown in radioactive (32)P...
will only label nucleic Acids
34
So, they grew...
viruses in two separate mixtures, P32 (nucleic acids) and S35 (proteins)
35
Viruses are also called
bacteriophages
36
Viruses...
inject their genes into bacteria and genes use bacterial cell to produce more viruses
37
Whatever genes are...
should be found inside the bacterial cells after infection
38
After growing viruses for several generations in S35(proteins)...
they infected the bacteria with the proteins
39
The result of this was..
the bacteria did not contain the 35S (protein)
40
Therefore this shows that...
genes must not consist of proteins since radioactive proteins were NOT INSIDE THE BACTERIA (genes not injected into bacteria, nor found in next gen of viruses)
41
After growing viruses for several generations in P32(nucleic acids)
they infected bacteria with these viruses
42
The result of this was...
the bacteria contained P32 (nucleic acids)
43
Therefore this shows that...
genes must consist of NUCLEIC ACIDS because these ENDED UP INSIDE CELL (injected into bacteria and found in next generation of viruses)
44
This experiment with Hershey and Chase was...
second definitive demonstration that genes were made of nucleic acids (DNA)
45
______ and ________ in _____ determined structure of DNA
Watson and Crick (1953)
46
Watson and Crick used information from
Rosalind Franklin, Erwin Chargaff, Maurice Wilkins
47
They described that DNA has...
double helix with sugar-phosphate backbone and nitrogenous bases projecting inward in complementary pairs
48
Monomer subunits of nucleic acids are
nucleotides
49
Nucleotides consist of
- pentose sugar - nitrogenous bases - phosphate group
50
Only different between RNA and DNA is
ON CARBON #2 RNA has hydroxyl (OH) on C#2 DNA has just H on C#2
51
DNA Backbone composed of
Sugars and phosphates
52
Sugars and phosphates connected with
phosphodiester linkage
53
The top 5 carbon and bottom 3 carbon
become connecting points for the chain
54
Four bases in DNA and RNA
DNA - ACG and T RNA - ACG and U
55
Difference between thymine and uracil
Thymine has methyl (CH3) group, uracil just has H
56
Purines are
Adenine and Guanine, DOUBLE RING
57
Pyrimidines are
Cytosine, Uracil, Thymine, SINGLE RING
58
Pairing relationships
A and T(U) - 2 H bonds C with G - 3 H bonds
59
The two DNA strands run in...
opposite directions, ANTIPARALLEL STRUCTURE
60
Watson and Crick published official paper in
April 25, 1953
61
Paper published in magazine
nature
62
They proposed in paper that the structure of DNA shows...
a copying mechanism, structure and function linked

Biology 224 (18 decks)

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