What observation did Griffith make in his experiments with Streptococcus pneumoniae?
The mouse did not survive when injected with a mixture of live, avirulent (smooth) Streptococcus pneumoniae and heat‑killed, virulent Streptococcus pneumoniae.
What results did Avery, McLeod, and McCarty obtain in their experiments with virulent bacteria?
DNase destroyed the transforming activity.
In forming a nucleotide, phosphorus is most often attached to the nucleoside at the C‑5′ position of the sugar.
Watson and Crick used information from several individuals to construct their model of DNA. Whose X‑ray diffraction studies were critical to their work?
If a double‑stranded sample of DNA has a base composition of 20% guanine, which of the following statements is true?
The amount of thymine must equal 30%.
RNA differs from DNA in all of the following ways except by
The 5′-3′ orientation of the polynucleotide strand.
Of the following DNA strands in combination with their complementary strands (forming double helices), three undergo a hyperchromic shift with a Tm of about 42°C. Which one has a Tm of 52°C?
Which of the following statements about the Cot1⁄2 or half‑association value of DNA fragments is true?
Shorter DNA molecules would associate more quickly (smaller Cot1⁄2 values).
If Avery, MacLeod, and McCarty had determined that the transforming molecule was a protein, what experimental results would not have been observed?
Heat‑killed cultures treated with RNase would transform the R cells.
What conclusion could be drawn if Hershey and Chase had found only 35S in their bacterial cells?
Protein is the genetic material.
35S is radioactive sulfur. Sulfur is found only in protein, not in DNA
To which positions in the sugar of a deoxyribonucleotide can a phosphate be esterified?
C-3′ and C-5′
Which of the following statements best describes the structure of a DNA molecule?
DNA is composed of a sugar‑phosphate backbone with bases projecting toward the inside of the backbone.
If two DNA strands of identical length were analyzed, which of the following statements would be true of their Tm or melting temperature?
DNA with a low AT content would melt more slowly.
Which of the following statements about the difference between DNA and RNA is false?
RNA is usually much longer than DNA.
Why is it important for a retrovirus to carry its own reverse transcriptase protein instead of making it from its reverse transcriptase gene after it infects a cell?
The retrovirus must make DNA before it can use the cell's molecular machinery to make reverse transcriptase. Normal cells do not contain reverse transcriptase.
Which of the following statements about DNA structure is true?
The nucleic acid strands in a DNA molecule are oriented antiparallel to each other, meaning they run in opposite directions.
Genetic material must be able to:
Replicate, Store information, express information, and allow variation by mutation.
How nucleotides linked?
Phosphodiester bond between the phosphate group at the C-5' positiong and the OH group on the C-3' position.
Nucleic acid electrophoresis seperated
DNA & RNA fragments by size such that smaller fragments migrate through a gel at a faster rate than large fragments
Fluorescent in situ hybridization (FISH)
used in identifying the chromosomal location of DNA of interest.
Evidence from eukaryotes...
same material; expression of eukaryotic proteins in bacterial with eukaryotic genes.