The Scientists
What is the name of the current model of DNA, named after the two scientists who figured it out?
The Watson and Crick Model
What is the name of the repeating units that make up DNA?
Nucleotides
What is the name of the primary enzyme involved in DNA replication?
DNA Polymerase
What is the name of the shape of DNA?
Double helix
Who used X-ray crystallography to tale 'pictures' to help solve the structure of DNA?
Rosalind Franklin
What is the name of the process Frederick Griffith described the led to the death of the mouse in his final experimental group?
Transformation.
-Sugar (deoxyribose)
-Phosphate
Why does DNA need to be replicated and during which stage of the cell cycle does replication happen?
What is a bacteriophage?
A virus that infects bacteria. Made of a protein capsule and DNA.
What type of sugar is found in DNA?
Deoxyribose
How did the Hershey-Chase experiment support the findings the DNA is the hereditary material?
By marking proteins and DNA in bacteriophages and seeing which group passed radioactive material to bacteria.
The structure of DNA can be compared to a ladder. What structures make up the rungs and what bond holds the two halves together?
Nitrogenous bases, hydrogen bonds.
What is meant when we say replication is semiconservative?
When the DNA unzips each strand serves as a template for a new strand. The result is two new identical strands, each containing one strand from the original DNA and one new strand.
What is a telomere?
The caps and the end of chromosome that protect DNA.
What are the pyramidines?
Cytosine and Thymine
Adenine-20
Thymine-20
Cytosine-30
Guanine-30
The 5' to 3' strand has the base sequence AACGTCAGCT. What would be the order 3' to 5' strand?
TTGCAGTCGA
How does replication differ in prokaryotes and eukaryotes?
Where would a covalent bond be found in DNA?
Between sugar and phosphate and between sugar and nitrogenous base.
Why was radioactive phosphorus used in the Hershey-Chase experiment?
Phosphorus is a key component of DNA, but not found in protein.
Both Rosalind Franklin and Chargaff presented evidence that DNA was double stranded. How did Chargaff's discovery support the double stranded view of DNA?
Chargaff's came up with base pairing, base pairing only works if there are two strands to pair up with each other.
How does the structure of DNA in a prokaryote differ from a eukaryote?
DNA in a prokaryote is a ring shape whereas in a eukaryote they are in strands. Otherwise the structure is the same.
What are three enzymes involved in DNA replication and what do they do?
Helicase- breaks hydrogen bonds
Primase- sets primers for replication sights
DNA polymerase- builds the new DNA strand
Ligase- Fills in the gaps in replication
Telomerase- builds telomeres at the end of chromosomes
Describe Frederick Griffith's experiment.
S-type bacteria-kills mouse
R-type bacteria-does not kill mouse
Heat killed S-type bacteria- does not kill mouse
Mix of dead S-type and R-type - kills mouse
Why are two strands of DNA held together by hydrogen bonds?
Hydrogen bonds are weak and can therefore be broken to unzip for replication.