Genetic Material Basics
What are the two types of nucleic acids that can serve as genetic material?
DNA and RNA
Which type of Streptococcus pneumoniae colony was virulent?
Smooth colonies
What organism did Hershey and Chase use in their experiment?
T2 bacteriophage
What method did Rosalind Franklin use to study DNA?
X-ray diffraction
This molecule consists of a nitrogenous base attached to a five-carbon sugar but does not contain a phosphate group.
Nucleoside
Genetic material must be able to make accurate copies of itself. What characteristic does this describe?
It must replicate faithfully.
Which type of Streptococcus pneumoniae colony was avirulent?
Rough colonies
Which radioactive isotope labeled the phage protein coat?
Sulfur-35 or ³⁵S
Which scientists proposed the three-dimensional model of DNA?
Watson and Crick
Which type of bond holds complementary nitrogenous bases together between the two DNA strands?
Hydrogen bonds
Genetic material must contain instructions that determine an organism’s observable characteristics. What characteristic does this describe?
It must encode the phenotype.
What happened when Griffith mixed heat-killed smooth bacteria with living rough bacteria?
The living rough bacteria transformed into virulent bacteria.
Which radioactive isotope labeled the phage DNA?
Phosphorus-32 or ³²P
Where are the sugar-phosphate backbones located in the DNA double helix?
On the outside of the helix.
One DNA strand has the sequence 5′-AGTCC-3′. What is the complementary sequence?
3′-TCAGG-5′
Why must genetic material have the capacity to vary?
Variation allows mutations and genetic differences to occur.
What name did Griffith give to the substance that changed the rough bacteria?
The transforming principle
Which radioactive label entered the bacterial cells during infection?
Phosphorus-32, the DNA label
What does it mean that the two DNA strands are antiparallel?
The strands run in opposite directions.
Scientists combine the protein coat of TMV strain X with the RNA of strain Y. What type of virus should the experiment produce, and why?
Strain Y because the RNA carries the virus’s genetic information.
Which type of genetics studies how genetic information is encoded, replicated, and expressed? Which type of genetics examines how genes pass from one generation to the next?
Molecular genetics, Transmission genetics
What did Avery, MacLeod, and McCarty identify as the transforming principle?
DNA
Why could radioactive carbon not distinguish DNA from protein?
Both DNA and proteins contain carbon, so both would become labeled.
Name four features of the Watson and Crick DNA model.
DNA has two antiparallel strands, forms a right-handed helix, has sugar-phosphate backbones on the outside, and has nitrogenous bases on the inside.
How did the TMV experiment expand the conclusion drawn from the Hershey–Chase experiment?
Hershey and Chase showed that DNA is genetic material in bacteriophages, while the TMV experiment showed that RNA can be genetic material in some viruses.