1. DNA Structure & Function

2. Cell Types
Prokaryotic – cells lack a true nucleus
Eukaryotic – cells have nucleus surrounded by a nuclear membrane

3. Nucleic Acids Organic Compound Consist of D N A & R N A Sugar
Phosphate group
Nitrogenous bases
D N A & R N A

4. DNA
Stands for DeoxyriboNucleic Acid
Nucleic – located in nucleus
Acid – acidic in nature

5. DNA is. . . Found in the nucleus of the cell
The genetic material in each cell
The chemical that processes and determines which proteins will be made by the cell

6. Nucleotides
Subunit of nucleic acids
5 Carbon sugar called deoxyribose
Phosphate Group
4 Nitrogen Bases

7. Nucleotide

8. Nitrogen Bases
Adenine = A
Thymine = T
Cytosine = C
Guanine = G

9. Nucleotides are connected by the attachment of the deoxyribose and the phosphate

10. Double Helix
The sides of the helix/ladder are the alternating phosphate groups and deoxyribose sugars
The rungs are paired nitrogen bases

11. Base Pairing
Only certain bases can pair with each other
Adenine with Thymine
Cytosine with Guanine

13. Hydrogen Bonds
The base pairs of the rungs (A - T & C – G) are held together by hydrogen bonds that are easily broken

14. Write the letters for the matching nucleotides on the strand of D N A:
Remember that Adenine always pairs with Thymine. Cytosine always pairs with Guanine
A T T A G C C G T A A G G A T C G
T A A T C G G C A T T C C T A G C

15. DNA Structure & Function
2. D N A Function

16. Functions:
D N A contains the genetic information to be passed on to the next generation
D N A must replicate (for mitosis and meiosis)
D N A is the template for R N A which is the template for proteins that determine a living organism’s traits

17. Gene
A segment of D N A that codes for a specific trait

18. DNA Structure & Function
3. D N A Replication

19. DNA Replication
Prior to cell division, the double stranded DNA molecule unwinds and is replicated
Each parent strand remains intact and a new complimentary side is attached

20. Process:
An “unwinding” enzyme breaks the hydrogen bonds between the nitrogen bases

21. Process:
2. DNA polymerase attaches free nucleotides to the exposed bases at the replication fork (according to base pair rules)

22. Process:
3. DNA ligase (another enzyme) seals the new nucleotides into a strand

23. Process:
4. Other enzymes go through and correct base pairing errors.

24. Process:
5. The resulting strands each have one new and one original piece of DNA
New Strand
Old Strand