1. The Human Genome

2. Chromosomes and DNA Replication
Vocabulary:
Chromatin
Histone
Replication
DNA polymerase
Key Concept:
What happens during DNA Replication?

3. The Review Prokaryotic cells do not have a nucleus
DNA molecules are located in the cytoplasm
Usually a circular DNA molecule and it is referred to as the cell’s chromosome
Eukaryotic cells have a nucleus
Can have 1000x more DNA than prokaryotic cells
DNA is located in the form of a number of chromosomes
# of chromosomes varies widely from species to species

4. DNA Length DNA molecules are LONG!
Ex: E. Coli (prokaryote that lives in human colon) has 4,639,221 base pairs
This equals approximately 1.6mm
Remember, bacteria are SMALL (1.6um in diameter)
It’s like putting a 300m rope into a backpack

5. How Does DNA Fit? Form a chromosome!
DNA coils around proteins called histones and then this chromatin supercoils around itself to form nucleosomes
Nucleosomes bunch together to form the visible chromosome

6. DNA Replication
before a cell divides, it must copy its DNA so that all cells have a copy of the genetic instructions
this process involves A LOT of enzymes!
 each half of the DNA double helix can serve as a "template" for the replication of another DNA double helix molecule
The strands are said to be complementary

7. Video

8. Hydrogen Bonds Breaking!
THE PROCESS
An enzyme unwinds & "unzips" DNA (separates the 2 DNA strands) by breaking the Hydrogen bonds between base pairs
Hydrogen Bonds Breaking!

9. the complementary base is inserted to each side of the DNA strand with the help of DNA Polymerase
Why does the “blue” always pair with the “green?”

12. 1 nucleotide
The sugar-phosphate groups are covalently bonded to the growing DNA chain (new "backbone")
COVALENT BOND

14. an enzyme (DNA Polymerase) will "proof-read" the order of bases & make corrections

15. SIMPLIFIED VERSION…
                                 

16. A Little More Complicated…