Chapter 10: DNA: Structure, Replication, and Variation Flashcards
In 1928, Frederick Griffith established that _______.
heat-killed bacteria harbor the constituent(s) necessary to convey genetic properties to living bacteria
Because some of the nonvirulent bacteria acquired properties of the virulent bacteria, instructions for this transformation must be carried by the virulent bacteria.
To be certain that the extract prepared from virulent cells still contained the transforming principle that was present prior to lysis, Avery _______.
incubated nonvirulent cells with the complete extract
The complete extract possessed the same ability to induce transformation in IIR bacteria as whole heat-killed IIS bacteria.
If Avery had observed transformation using only the extracts containing degraded DNA, degraded RNA, and degraded protein, but NOT the extract containing degraded polysaccharides, he would have concluded that _______.
polysaccharides are the genetic material
Failure to transform suggests that the chemical degraded in that preparation is the one responsible for transformation, in this case polysaccharides.
The Hershey and Chase experiments involved the preparation of two different types of radioactively labeled phage. Which of the following best explains why two preparations were required?
It was necessary that each of the two phage components, DNA and protein, be identifiable upon recovery at the end of the experiment.
Because it was concluded that the component associated with bacteria at the end of the experiment must be the genetic material, it was critical that the component be identifiable as either DNA or protein.
Which of the following statements best represents the central conclusion of the Hershey-Chase experiments?
DNA is the identity of the hereditary material in phage T2.
Because phage DNA and not protein was associated with bacteria at the end of the experiment, it could be concluded that DNA - not protein - must be the genetic material.
Which of the following outcomes would be most likely if the Hershey-Chase experiments were repeated without the step involving the blender?
Both preparations of infected bacteria would exhibit radioactivity.
Instead of being removed from the preparation, the “ghosts” would be retained. Because both bacterial preparations would include ghosts as well as viral DNA, both would be radioactive, one with P32, one with S35.
What results did Avery, McLeod, and McCarty obtain in their experiments with virulent bacteria?
DNase destroyed the transforming activity.
Treatment of the transforming principle with DNase destroyed the DNA and thus its ability to transform bacteria.
What observation did Griffith make in his experiments with Streptococcus pneumoniae?
The mouse did not survive when injected with a mixture of live, avirulent (rough) Streptococcus pneumoniae and heat-killed, virulent Streptococcus pneumoniae.
Something in the heat-killed preparation was able to transform the avirulent strain to a virulent form.
Guanine and adenine are ____ found in DNA.
Guanine and adenine are indeed purines found in DNA; thymine and cytosine are the pyrimidines found in DNA.
The following statements about DNA structure are true?
The nucleic acid strands in a DNA molecule are oriented antiparallel to each other, meaning they run in opposite directions.
The 5′–3′ orientation of each chain runs in opposite directions.
What is the complementary DNA sequence to 5′ ATGCTTGACTG 3′?
5′ CAGTCAAGCAT 3′
Regarding the structure of DNA, the covalently arranged combination of a deoxyribose and a nitrogenous base would be called a(n) ________.
nucleoside
If 15% of the nitrogenous bases in a sample of DNA from a particular organism is thymine, what percentage should be cytosine?
35%
Identify three possible components of a DNA nucleotide.
deoxyribose, phosphate group, thymine
DNA and RNA have similar structures: a pentose sugar with a nitrogenous base and a phosphate group. DNA and RNA differ in the type of pentose sugar each possesses (DNA has deoxyribose; RNA has ribose) and in one base (DNA has thymine; RNA has uracil).
List 3 main differences between DNA and RNA.
RNA often occurs as both single- and partially double-stranded forms, whereas DNA most often occurs in a double- stranded form.
Ribose in RNA replaces deoxyribose in DNA.
Uracil in RNA replaces thymine in DNA.
One of the most common spontaneous lesions that occurs in DNA under physiological conditions is the hydrolysis of the amino group of cytosine, converting the cytosine to uracil. What would be the effect on DNA structure of a uracil group replacing cytosine?
A base substitution of G:C to A:T after two rounds of replication.
In 1953, Watson and Crick published a paper that described the ____.
In 1953, Watson and Crick published a paper that described the structure of DNA.
RNA differs from DNA EXCEPT what way?
the 5’-3’ orientation of the polynucleotide strand
Both RNA and DNA have the same 5’ amino group and 3’ hydroxyl group chemical orientation.
All EXCEPT which of the following statements are evidence that DNA, and not protein, is the genetic material in eukaryotes as well as bacteria?
DNA has four nucleotides.
DNA is located only where the primary genetic function is known to occur.
UV light is most mutagenic at a wavelength at which DNA and RNA strongly absorb.
Introduction of a cloned DNA into another organism results in the production of the corresponding protein product.
DNA has four nucleotides, and proteins have 20 amino acids. Protein was thought to have the chemical diversity and complexity necessary for the genetic material and DNA was not.
Which technique can be used to identify the location of genes on a chromosome?
FISH
Fluorescent in situ hybridization is a technique used to identify the location of a gene or a specific DNA sequence on a chromosome. The technique involves hybridizing single-stranded DNA probes, labeled with a fluorescent dye, to their complementary DNA strand in the genome. Their location on the chromosome can be viewed under a fluorescent microscope.
___ has no sulfur, and ____ have no phosphorus.
DNA has no sulfur, and proteins have no phosphorus.
In a DNA sequence, the purine ____ always pairs with the pyrimidine ____ , and the purine ____ always pairs with the pyrimidine ____.
In a DNA sequence, the purine adenine always pairs with the pyrimidine thymine, and the purine guanine always pairs with the pyrimidine cytosine.
Write the complementary sequence for the following DNA sequence, in order from 3’ to 5’:
5′−CGATATTGAGCTAAGCTT−3′
3′−GCTATAACTCGATTCGAA−5′
The base pair adenine-cytosine occurs very rarely in nature. It only happens during a mutation event. When the DNA is replicated, one of the two daughters will contain a guanine-cytosine base pair in the location of the mutation, and the other daughter will contain an adenine-thymine base pair.
How does the number of hydrogen bonds between the two bases affect the stability of a base pair?
All other factors being equal, the renaturation of the three classes of complementary nucleic acid sequences occurs in what order, from fastest to slowest?
A) unique sequences
B) moderately repetitive sequences
C) highly repetitive sequences
C,B,A
