BIO 143 Chapter Notes - Chapter 11: Dna Replication, Semiconservative Replication
127 views2 pages
Fall 2010—BIO 143 STUDY GUIDE: Chapter 11
Chapter 11: DNA—The Molecule of Heredity
I. How did scientists discover that genes are made of DNA?
A. Hereditary information is found in discrete units called genes
1. Genes: segments of DNA located on chromosomes
2. Chromosomes are composed of DNA and protein
B. Transformed bacteria revealed the link between genes and DNA
1. In the 1920s, Griffith worked with bacteria that caused pneumonia
a. He worked with two strains: R and S; R did NOT cause
pneumonia in mice and S DID cause pneumonia in mice
b. Mixed heat-killed S-strain and living R-strain—what happened?
Understand the concept of transformation. How is the mixed
strain an example of this concept?
2. The transforming molecule was identified to be what? What other
experiment was conducted to determine whether the genetic material
was protein or DNA?
II. What is the structure of DNA?
A. DNA is composed of four nucleotides
1. Four kinds of nucleotides that differ depending on the nitrogen-
2. What are the three components of each nucleotide?
3. What are the four bases?
4. What does Chargaff’s rule state?
B. DNA is a double-helix of two nucleotide strands
1. What does the DNA backbone consist of?
C. What type of bond holds the two strands together between the
1. The backbones are anti-parallel
a. Each strand is directional: free sugar on one end, phosphate
on the other end
b. The directions of the two strands are opposite
c. What are the pairing rules? This is called complementary
III. How does DNA replication ensure genetic constancy during cell division?
A. Replication of DNA is a critical event in the cell cycle
1. What is the purpose and outcome of DNA replication?
2. Ingredients involved in DNA replication
a. Parental DNA strands
b. Enzymes—what are they and what are their functions? There
are three of them we discussed in lecture
c. Free nucleotides