1. Today is Tuesday, November 19th, 2013
In This Lesson:
Unit 5
DNA Structure and Replication
(Lesson 1 of 3)
Today is Tuesday, November 19th, 2013
Pre-Class:
Today we start DNA. Tell me everything you know about it. You must write this down (the more scientific, the better).
(But write down everything you can)
What are the names of all the DNA bases we’ve learned so far?
Also, today is our Strawberry Lab. It’s in the turn-in box – go get a copy! Also get a small paper towel.

2. Today’s Agenda Strawberry DNA Extraction
Where we are and where we’ve been
Challenge Questions
DNA Structure
DNA Replication
As in, what happened in S phase.
DNA Pickup Line?
Where is this (all) in my book?
Pages

3. By the end of this lesson…
You should be able to identify the detailed structures of DNA.
You should be able to describe the process by which DNA copies itself.

4. Strawberry DNA
The most delicious DNA out there…

5. Orientation First, we studied atoms. Atoms make up all matter.
Some of this matter is considered organic, and is organized into four major groups.
Life-supporting organic matter has non-living functions, like diffusion and osmosis.

6. Orientation
Diffusion and osmosis help living things carry on life and undergo respiration.
Life’s smallest unit is the cell.
There are prokaryotes and eukaryotes, and they all have different organelles.
Even among eukaryotes, there are plant cells and there are animal cells.

7. Orientation All cells, however, need to grow and reproduce.
For body cells (also known as somatic cells), growth occurs through mitosis.
Mitosis is a process in which the genetic material (DNA) is copied and the nucleus (and right after, the cell) divides.

8. Orientation Sex cells (or gametes), use the process of meiosis.
The chromosomes in your cells are made of DNA, which makes you who you are.
Today we will begin learning about how DNA copies and how it “codes” for proteins, which is the molecular basis for genetics.

9. Challenge Questions
To the whiteboards!

10. Introducing DNA
Video: DNA Introduction

11. Johann Friedrich Miescher
DNA’s Discovery
Johann Friedrich Miescher
Discovered by Friedrich Miescher in 1869.
Noticed something in pus in discarded surgical bandages.
Called it “nuclein,” but other than a guess didn’t know it had any role in heredity.

12. & DNA’s Discovery DNA’s structure was discovered in 1953 by:
James Watson
Francis Crick
&
With some big help from…
Maurice Wilkins
And all three were exploiting the work of…
Rosalind Franklin

13. DNA Overview Video Video: DNA Overview
Video: TED – Judith Hauck – The Twisting Tale of DNA

14. DNA The big important statement:
DNA in a long strand and wrapped around proteins is called chromatin. When condensed, a piece of chromatin is called a chromosome.
Segments of the DNA strand are called genes. These genes tell the cell what proteins to make, which determine your traits.
Genes are like chapters in the book of DNA.
Each cell has the whole book, but depending on their jobs, the cells read different chapters.

15. DNA and Review DNA is a nucleic acid, a long string of nucleotides.
DNA takes the shape of a double-helix.
There are four kinds of nucleotides:
Adenine
Cytosine
Guanine
Thymine

16. Nucleotide Review Each nucleotide has a:
Sugar molecule with 5-carbons (pentose)
Deoxyribose in DNA
Ribose in RNA
Phosphate group
Phosphorous-based molecule
Nitrogenous base (makes the nucleotide unique)
Adenine
Thymine
Cytosine
Guanine

17. Nucleotide Structure Review
SKETCH ME! I’m useful!
SKETCH ME! I’m useful!
Nucleotide Structure Review
SKETCH ME! I’m useful!
SKETCH ME! I’m useful!
Guanine
Cytosine
Thymine
Adenine
SKETCH ME! I’m useful!
SKETCH ME! I’m useful!

18. Nucleotide Structure Review
More “scientific”

19. Nucleotides and Nucleosides
Just so you know, you’ll occasionally hear of a nucleoside.
The only difference between a nucleoside and a nucleotide is that a nucleoside is just a sugar and nitrogenous base – no phosphate group.

20. DNA
Surrounding the base pairs and forming the sides of the “ladder” is a sugar-phosphate backbone.
The backbone is made of an alternating pattern of sugars (deoxyribose) and phosphate groups.

21. DNA DNA stands for Deoxyribonucleic Acid.
By hydrogen bonds, cytosine bonds to guanine and adenine to thymine.
A ↔ T
C ↔ G

22. Base Pairs
(Held together by hydrogen bonds)
How can we remember this?

23. DNA Unwound (Basic) ---H--- ---H--- ---H--- P Adenine Adenine P
Deoxy-ribose P
Adenine
Adenine
Deoxy-ribose P
Guanine
Thymine
---H---
DNA Unwound (Basic)
Deoxy-ribose P
Cytosine
---H---
One Nucleotide P
Deoxy-ribose
---H---
Thymine

24. DNA Unwound (Advanced)
Deoxy-ribose P
Adenine
Thymine
Deoxy-ribose P
Guanine
Adenine 5’ 3’
---H---
DNA Unwound (Advanced)
PD Bond
Deoxy-ribose P
Cytosine
PD Bond
---H---
PD Bond P
PD Bond
Deoxy-ribose
---H---
Thymine 5’ 3’

25. Complementary Base Pairs
Video: DNA Complementary Base Pairs

26. DNA Replication
There comes a time in (almost) every DNA molecule’s life when it needs to be replicated (copied).
That time would be S phase.
DNA must be copied before mitosis.
Here’s the general process:
Unwind the double-helix.
Break the hydrogen bonds (“unzip” the DNA).
Use enzymes to replace base pairs on each side.

27. Looks like this… [IMPORTANT]
The “old” strand is sometimes known as the template strand because it’s a model for the new one.
Note that even though there are two strands forming down here, each is only “half” new.

28. Looks like this… [IMPORTANT]

29. DNA Replication - Schematic
Video: DNA Replication – Schematic

30. DNA Worksheet Try problems 1 and 2 on your DNA worksheet. 1: A C
1: T G
2: G A A G G C G T T

31. DNA Worksheet Try problems 3, 4, and 5 on your worksheet.
3: T T G C A A G T C 4:
5. Always three rings (keeps the same width).

32. DNA Worksheet Try problems 6 and 7 on your worksheet.
6: Sugar/Phosphate Backbone
7: A ↔ T, C ↔ G
7: Purines – 2 rings, Pyrimidines – 1 ring

33. Time for a Game!
In this game, you will be practicing the process of replication.
Don’t mess up the base pairs!
You’ll also use the DNA you make to figure out which organism it comes from.

34. Adding some names…
In that activity, we matched DNA bases to one another. Ts were with As, Gs with Cs.
Because they go together, we call these pairings complementary.
“The complementary base of G is C.”

35. Enzymes
The role we played – breaking the DNA “ladder” and replaced missing base pairs – is a role played by enzymes in the human body.
There are two main enzymes:
DNA Helicase
Unzips the DNA double-helix (breaks H-bonds).
DNA Polymerase
Adds complementary base pairs.

36. DNA Helicase Animation

37. DNA Replication – Molecular
Video: DNA Replication – Molecular

38. DNA Polymerase makes new DNA DNA Helicase breaks H-bonds
Deoxy-ribose P
Thymine
Cytosine
Adenine
Deoxy-ribose P
Thymine
Deoxy-ribose P
Adenine
Adenine
Deoxy-ribose P
Guanine
Thymine H
---H--- H
Replication
Deoxy-ribose P
Guanine
Deoxy-ribose P
Cytosine
Strands move apart
DNA Polymerase makes new DNA
DNA Helicase breaks H-bonds H
---H--- H
Deoxy-ribose P
Adenine
Deoxy-ribose P
Thymine H
---H--- H P P

39. Enzymes For your information, there are also two other enzymes:
DNA Ligase
Seals up breaks in the DNA code that occur naturally during replication.
RNA Primase
Lays down a “primer” after which DNA Polymerase can start to work.
I will not hold you to these on the quiz/core, but they will come up.

40. What We Know About DNA
We always hear that DNA is the genetic material of the cell, or the command center, or what is responsible for you. Whatever. What exactly does that mean?
DNA helps the cell “decide” which proteins to make.
The proteins are different for everyone.
That’s why your DNA makes you unique.
And why we can use DNA to test potential criminals.

41. Time for a Flowchart
Find some room in your notebooks.

42. Guiding Question How can one person have two different eye colors?
Your questions? What do you want to know?

43. Time for a Gizmo
It’s called Building DNA, and that’s just what you’ll be doing.
As usual, you’ll need a second window open for Quia:
Building DNA Gizmo
[Log-in Instructions]

44. Exit Ticket (Part One)
What are the full names of the four nitrogenous bases in DNA?
Which are purines, which are pyrimidines?
Which bases pair to which?

45. Exit Ticket (Part Deux)
Which enzyme “unzips” the DNA double helix?
Which enzyme places new nucleotides to complete the base pairs?