Name ________________________________________ Date _______________________ Period _____
DNA: The Stuff of Life (Notes Organizer) 1. Frederick Griffith – 1928 a. Who was Griffith and what was his scientific interest?
b. Griffith’s experiment led to the discovery that ______________________ _______________________ could be passed between living organisms. c. Describe Griffith’s experiment:
d. The harmless strain of bacteria transformed into the disease-causing strain. What is transformation?
2. Oswald Avery – 1944 a. Why did Oswald Avery repeat Griffith’s work?
b. Oswald concluded that the ____________ molecule was the genetic material passing between bacteria. 3. Hershey and Chase – 1952 a. Alfred Hershey and Martha Chase studied ____________________. b. What is a bacteriophage and what is it made up of?
c. Hershey and Chase wanted to determine whether proteins or DNA were released by viruses. They did this by growing them in cultures containing _________________________ ______________________. d. Radioactive Phosphorous attaches to which part of the bacteriophage?
e. Radioactive Sulfur attaches to which part of the bacteriophage?
Describe the overall purpose of the Hershey and Chase experiment:
g. What was the conclusion?
4. Erwin Chargaff – 1950 a. Chargaff studied the four ______________________ _________________________. b. What did Chargaff’s data illustrate?
c. What is “Chargaff’s Rule?”
d. The nitrogen bases exist in two forms. i.
__________________________ are single ring bases. Examples:
ii. __________________________ are double ring bases. Examples:
5. Rosalind Franklin – 1951 a. What scientific technique was used by Rosalind Franklin in order to take “pictures” of DNA?
b. Describe the significance of Franklin’s Photo 51.
6. James Watson and Francis Crick – 1951 a. Watson and Crick built the first accurate __________________ representing the structure of DNA. b. Describe Watson and Crick’s DNA model:
7. DNA Structure a. DNA is often thought of as a “_____________________ _______________________” because of its double helix shape. b. What forms the “rails,” or sides, of the ladder?
c. What forms the “rungs,” or steps, of the ladder?
d. Watson and Crick discovered that hydrogen bonds can only form between certain pairs. i. How many hydrogen bonds form between Adenine and Thymine?
ii. How many hydrogen bonds form between Cytosine and Guanine?
iii. In other words, a ________________________ is always paired with a ____________________. e. Nucleotides are the monomers of the DNA macromolecule. What three parts make up a nucleotide?
8. DNA Replication a. ________________ ________________ b. What is replication?
c. Describe the purpose of DNA replication:
d. When does DNA replication occur?
e. Each strand of the original DNA serves as a _____________________ for the new strand. i. This is known as what?
Use this T-chart to describe DNA replication in prokaryotic and eukaryotic organisms. Prokaryotic DNA Replication
Eukaryotic DNA Replication
g. The sites where separation and replication occur are known as __________________ ______________.
9. Process of DNA Replication. a. DNA must first unwind and “unzip.” What enzyme is responsible for the unwinding and unzipping of the DNA molecule?
b. The enzyme _______ ___________________ then adds a short segment of RNA, called an RNA primer, to each DNA strand. c. Which enzyme continues adding appropriate DNA nucleotides to the chain of the new strand?
d. What are Okazaki fragments?
e. Which enzyme is responsible for linking together together the many Okazaki fragments?
10. DNA Replication Practice a. Give the complementary sequence for the following strand of DNA: DNA 5’ A
Properly label the image below identifying all components of DNA replication.
b c a g h d f e i