1. Please take out your lab book and prepare for a warm-up!
Biology 1/18 and 1/19
Please take out your lab book and prepare for a warm-up!

2. Warm-Up 1/18 and 1/19
Last class you extracted DNA from a strawberry. If I extracted YOUR DNA, would it look the same or different? Why?

3. DNA Structure

4. DNA’s Job
DNA carries information from one generation to the next (parent to child)
Every cell in your body has the same 46 chromosomes of DNA
DNA determines how you look by making proteins
Most of these proteins are enzymes, which are the tools that build your body

5. Structure of DNA Long molecule made of nucleotides
Every nucleotide has three parts:
5 carbon sugar
Phosphate group
Base (contains Nitrogen)

6. Structure of DNA Nucleotides link to form strands of DNA
Nucleotides have the same sugar and phosphate
There are four different bases: adenine (A), guanine (G), cytosine (C), thymine (T)

7. Nucleotide Practice
Phosphate
Following this example, draw the four different types of nucleotides found in DNA
Hint: the only difference between them is the letter!
Adenine (A)
Sugar

8. How do Nucleotides Fit Together?
Sugar and phosphate make up the backbone; bases are protected in the middle
DNA strands have a 5’ end, which starts with a phosphate, and a 3’ end, which ends with a sugar
DNA is always built in the 5’ to 3’ direction!

9. How Bases Pair Up A and T always pair up; G and C always pair up
Chargaff’s Rule:
The percentages of A and T are the same within a DNA molecule; so are G and C!
All organisms follow this rule:
[A] = [T] and [G] = [C]

10. Percentage of Bases in Organisms
Streptococcus
29.8
31.6
20.5
18.0
Yeast
31.3
32.9
18.7
17.1
Herring
27.8
27.5
22.2
22.6
Human
30.9
29.4
19.9
19.8

11. The Double Helix DNA is made of two complementary strands
The strands are wound in a double helix
The strands are held together by hydrogen bonds
Hydrogen bonds result from attractions between H, N, and O on the bases

12. The Double Helix

13. DNA Pioneers
James Watson (US) and Francis Crick (UK) created the first model of the double helix in 1953
They deduced the structure using information from Rosalind Franklin, who created an x-ray photograph of it
Franklin passed away before receiving the Nobel Prize, but it was awarded to Watson and Crick

14. two nucleotides for you!
Self Test!!!
Draw one strand of DNA with the sequence AGTACG. Then, draw in the other strand, pairing A with T and G with C
I drew the first
two nucleotides for you!

15. It looked just like this, right?
Now label the 5’ and 3’ ends of each strand!

16. Final Exam Info. Period 4: Wed.,1/24 Period 5,6,7:Thurs.,1/25
Worth 1.5 Unit Tests
Open Notebook
All notes must be hand-written!
50 Multiple Choice
ALL MISSING WORK DUE WITH FINAL!
Topics:
Chapter 13: Plate Tectonics
Chapter 6: Evolution
Chapter 7: Genetics
Chapter 8: Structure and Function of macromolecules

17. Today’s Task
Find the major concepts from Chapters 6 and 13 in your lab book
Add info, if needed.
Highlight!