BIO 392 NOTES CHAPTER 12: DNA & RNA
DNA STRUCTURE How do we go from genotype to phenotype?
What do you remember?
1. What does DNA stand for? ______
2. Where is DNA found in the cell? ______
3. What are the monomers of nucleic acids called? ______
4. Write at least 5 other things about DNA that you know:
Context:
We have just been studying human heredity. How are our genes instructions?
1. ______base pairs
2. ______individual bases
3. Bases (______) spell out genes (______) that result in the phenotype (______)
a. Some spell out bad stories (______)
I. DNA
A. Structure
1. Shape: ______
2. Built from: ______
Which consist of:
a. ______
b. 5-carbon sugar: ______
c. ______
i. 4 types
B. Nucleotides
1. What differences do you see?
2. What are the 4 Nitrogenous bases?
a. PURINES : ______& ______
b. PYRIMIDINES: ______& ______
Label the Diagram:
A. Pyrimidines
B. Purines
C. Adenine
D. Guanine
E. Cytosine
F. Thymine
G. Phosphate group
H. Deoxyribose
II. DISCOVERIES
A. Erwin Chargaff
1. Studied: DNA of numerous organisms
2. Observed: # of ______was always similar to the number of ______
# of ______was always similar to the number of ______
3. Chargaff’s Rule
a. ___ always bonds to ____
b. ___ always bonds to ____
B. Base Pairing
1. The bonds between bases (A & T, G & C) are
______
a. Fairly weak bonds
2. A and T are weaker
a. Only ______
3. G and C are stronger
a. ______
RECAP
1. What are the three main components of the DNA structure?
2. What is a difference between the DNA and RNA backbone?
3. What are the names of the 4 bases?
4. Which are pyrimidines?
5. Which are purines?
6. What does Chargaff’s rule say about pairing?
II. Discoveries continued
C. Rosalind Franklin
1. Franklin and Maurice Wilkins at King's College, (London, England) performed
______
2. Franklin noticed a diffraction pattern in DNA that showed that DNA was
____-stranded and a ______-shape
D. Watson and Crick
1. Used Franklin’s X-ray image to build a model of the DNA structure
2. The Double Helix
a. ______backbone on the outside
b. Bases on the inside
i. A = T have 2 bonds
ii. C = G have 3 bonds
E. Building the ladder:
1. 5’ to 3’ à “five prime to three prime”
A chromosome is made of DNA
III. DNA Packaging
à label the diagram below
RECAP
1. What was the name of the technique Rosalind Franklin used to analyze DNA’s shape?
2. What types of bonds are formed between bases?
3. How many bonds form between A and T?
4. What is the name of the protein that DNA intertwines with?