1. Nucleic Acid Structure
DNA and RNA

2. Where are Nucleic Acids located?
In the nucleus
DNA stays
RNA can leave
Nucleus

3. DNA and RNA Structure DNA RNA Double Helix Nucleotide Strands
Basic Building Block of DNA
Composed of
Sugar (Deoxyribose)
Phosphate group
Base (A, T, G or C)
Single Strand
Nucleotide strands
Basic Building Blocks of RNA
Composed of
Sugar (Ribose)
Phosphate group
Base (A, U, G, or C

4. Create the appropriate nucleotides.

5. DNA and RNA
Backbone
Alternating sugar and phosphates

6. What are the bases?
Purines
Pyrimidines

7. Place your nucleotides in two piles: purines and pyrimidines.
Which nucleotide are we missing? Why?

8. Which bases join together?
DNA
RNA
A with T
Purine with pyrimidine
G with C
How are they joined?
Hydrogen Bonds
These strands are complements! Allowing for DNA replication to take place.
Remember  Single Strand
RNA pairs with DNA
A (DNA) with U (RNA)
T (DNA) with A (RNA)
G (DNA) with C (RNA)
C (DNA) with G (RNA)
How are they joined?
Hydrogen Bonds

9. Line Up
5’ to 3’
Antiparallel

10. Create your DNA strand.

11. DNA Replication
Why?

12. DNA Characteristics Double Helix Antiparallel?
Base pairs?
Antiparallel?
5’-3’
3’-5’
Replication is semi-conservative?

13. Begin replication on your strand.
What has to happen first?

14. DNA Replication Step 1 Double Helix needs to be unwound and unzipped
Creates a replication bubble / fork
DNA Helicase
What is that?
Creates a leading and lagging strand
Leading – replication occurs continuously
Lagging – occurs in fragments called Okazaki fragments

15. DNA Replication Step 2 Step 3 Step 4
How does replication know where to begin?
RNA Primase
Lays down a primer
RNA – ribonucleic acid (both oxygens, uracil instead of thymine, single strand)
Step 3
DNA Polymerase
Lays down complementary base pairs
5’  3’
The replicated strand always starts from the phosphate end and replicates towards the sugar end.
Continues until done
Step 4
DNA Polymerase changes the RNA Primer to DNA

16. DNA Replication Step 5 What are we left with?
Ligase comes in and fills the Okazaki fragment gaps.
What are we left with?
Why do we call it semi-conservative again?

17. Your Turn Create a flow chart of DNA Replication
Start from the very beginning.
Your sequence is
5’-TGCACGAATG-3’
Create a Double Helix using that sequence
You have a template to trace from the picture handout I gave you
When you unwind make sure you show the structure of each nucleotide
Use the template from the picture handout I gave you.
Make sure you show everything in detail of what is going on.
Make sure you have an explanation of what is going on under each picture.
Be neat and detailed.
Due Tomorrow.