1. Almost everything you need to know about DNA

2. Deoxyribonucleic Acid
Also known as DNA
Strands of DNA are called chromatin
Genes are the blueprint for all of the proteins are body makes

3. What is DNA made of? The backbone of the ladder is made up of: Sugar
Phosphate

5. Nucleotides
The middle of the ladder is made up of only 4 nucleotides or bases! These code for ALL LIFE!!!
-adenine (A)
-guanine (G)
-cytosine (C)
-thymine (T)

6. A always goes with T Adenine ALWAYS goes with Thymine
This is the only way they fit in the ladder!

7. G always goes with C Guanine always goes with cytosine
It’s the only way they will fit in the ladder!

8. Backbone is ANTIPARALLEL
DNA has a 3’ end and a 5’ end (this is based on the carbon in the ribose sugar)
Each parent strand is opposite, therefore, they are antiparallel

9. Nucleic acid pairs are called BASE PAIRS

10. DNA is stored in CHROMATIN
One molecule of DNA is stored in the nucleus as long strands of CHROMATIN
When a cell wants to divide into two cells, it must condense its chromatin

11. Condensed chromatin makes CHROMOSOMES
When all of the DNA has finally turned into chromosomes, the chromosomes copy themselves, and then divide into two cells.

12. Cell Cycle
Every cell in your body goes through a cell cycle. Its like its own life mini life cycle.
What kinds of cells have to multiply throughout your life?
What kinds of cells usually stop multiplying as an adult?

13. Cell Cycle The life of a cell has 3 stages called the cell cycle:
1. Interphase
2. Mitosis
3. Cytokinesis

14. Cell Cycle
One cell divides, and makes 2! TWINS!!!!

15. 1. Interphase It’s the longest phase
It is when the cells are carrying out functions to survive, and preparing for the second step, mitosis.

16. Interphase DNA replicates itself in interphase!
We have 3,000,000,000 nucleotide base pairs in our DNA that needs to be replicated!
How does DNA replicate?

17. DNA Replication 1. The strands unwind
2. Each strand is a “parent” strand
3. A new daughter strand attaches to each parent strand.
4. You now have two copies of the DNA in one cell!

18. DNA Replicated!-We now have double the amount of chromosomes in the nucleus!

19. But Exactly How Does DNA Replicate?
DNA has genes that code for unwinding
These are called “Origins”
Where the DNA unwinds is the “Replication Fork”
The turquoise strand is the parent strand. The lime green strands are the new daughter strands.

20. Helicase
This is the enzyme that causes the parent strands of DNA to separate, so replication can occur.

21. DNA Polymerase Anything that ends in “ase” is an enzyme!
DNA Polymerase is an enzyme that adds new nucleotide bases to the parent strands.

22. DNA Polymerase
Adds nucleotides, and will also make corrections when wrong nucleotides are added!
Is highly conserved in evolution! All organisms have very similar DNA polymerase.

23. DNA Polymerase
It reads DNA from the 3’ end to the 5’end

24. Leading Strand Reads from 3’ to 5’
Therefore, nucleotides are added 5’ to 3’
Its so easy and everyone is happy
DNA is replicated in one continuous fashion!

25. Lagging Strand

26. Lagging Strand
DNA Polymerase can only replicate small chunks at a time, since DNA HAS to be read 3’ to 5’
These small chunks are called Okazaki fragments

27. Empty Spaces Between Okazaki Fragments!
There are many ‘nicks’ in the DNA between the Okazaki fragments
Luckily, another enzyme, LIGASE, will come along and fill in this missing information
DNA replication video
DNA replication video2

28. Function in DNA replication
Enzyme
Function in DNA replication
DNA Helicase
Also known as helix destabilizing enzyme. Unwinds the DNA double helix at the Replication Fork.
DNA Polymerase
Builds a new duplex DNA strand by adding nucleotides in the 5' to 3' direction. Also performs proof-reading and error correction.
DNA clamp
A protein which prevents DNA polymerase III from dissociating from the DNA parent strand.
Single-Strand Binding (SSB) Proteins
Bind to ssDNA and prevent the DNA double helix from re-annealing after DNA helicase unwinds it thus maintaining the strand separation.
Topoisomerase
Relaxes the DNA from its super-coiled nature.
DNA Gyrase
Relieves strain of unwinding by DNA helicase.
DNA Ligase
Re-anneals the semi-conservative strands and joins Okazaki Fragments of the lagging strand.
Primase
Provides a starting point of RNA (or DNA) for DNA polymerase to begin synthesis of the new DNA strand.
Telomerase
Lengthens telomeric DNA by adding repetitive nucleotide sequences to the ends of eukaryotic chromosomes.