1. Nucleic Acids

2. Nucleic acids
Connects all life together; it has the same structure in all organisms

3. Nucleic Acids There are 2 types of nucleic acids
DNA (Deoxyribonucleic acid)
RNA (Ribonucleic acid)

4. Nucleic acids Location DNA RNA In the nucleus ONLY
In the nucleus and the
cytosol

5. Nucleic Acids Purpose or Responsibility
To store and transmit genetic information

6. Nucleic acids Purpose or Responsibility Codes for proteins
Proteins are responsible for giving you all of your heritable characteristics and for all cellular activity
DNA --> RNA --> Protein

7. Nucleic acids
Nucleic acids are macromolecules
Large molecules

8. Nucleic acids
Macromolecules are made up of monomers - small repeating subunit
A bunch of bricks makes a brick house.

9. Nucleic acids
Nucleic acids are macromolecules that are made up of monomers called nucleotides
A bunch of nucleotides make a DNA or an RNA molecule

10. What is a nucleotide? A nucleotide has three parts A sugar A phosphate
A nitrogen base

11. Differences between DNA and RNA
Sugar: Ribose
Nitrogen bases
A - Adenine
U - Uracil
C - Cytosine
G - Guanine
DNA
Sugar: Deoxyribose
Nitrogen bases
A - Adenine
T - Thymine
C - Cytosine
G - Guanine

12. Differences between DNA and RNA
Shape: Double helix, like a twisted ladder
RNA
Shape: Single chain; like a strand of hair

13. The shape of DNA!
Rungs - steps on the ladder = the nitrogen bases: (A, T, C, G)
Rails - what you hold on to = the sugar / phosphate backbone

14. DNA and RNA bonding
When nitrogen bases bond together, they can only bond to one type of base.
Bases that bond are called complementary bases.

15. Complementary base pairing rules
DNA
A:T
G:C
(AT, Good Cat)
RNA
A:U
G:C

16. Who Discovered the Shape of DNA?
James Watson
Francis Crick
Rosalind Franklin
Maurice Wilkins
1953

17. DNA Replication

18. DNA Replication
DNA replication is the process of copying DNA

19. DNA replication
Step 1
Enzymes called helicases help separate the two chains

20. DNA Replication
Once the two chains are separated, each chain acts as a template for a new chain
A template is a pattern or a guide used to make something accurately

21. DNA replication
Step 2: An enzyme called DNA polymerase binds to the separated chains of DNA and makes new strands of DNA that are complementary to the old strands of DNA

22. DNA replication

23. DNA replication

24. DNA replication
DNA replication is semi-conservative because when two identical DNA strands are made, half of the strand is new and half of the strand is old

25. Complementary nature
Write the complementary DNA strand A C T G

26. Complementary nature Write the complementary DNA strand A - T C - G
G - C

27. Accuracy and Repair A mutation is a change in the nucleotide sequence
Original sequence
A - T
T - A
C - G
G - C
Mutated sequence
A - T
T - A
C - A
G - C
An error occurs during replication and A bonds to C instead of G. This is called a mutation.

28. Accuracy and Repair
During replication, there is about one error per 1 billion nucleotides
There are few errors because cells constantly proofread and repair damage

29. What causes mutations? Mutagens: substances that cause mutations
Certain chemicals
UV radiation
X-rays

30. What happens when mutations occur?
Usually nothing, mutations are mostly neutral
Sometimes mutations are harmful and can cause disease, cancer, and death

31. What happens when mutations occur?
Sometimes mutations are beneficial and improve an individual’s chance of survival

32. How fast does DNA replicate?
In humans about 3 hours
Bacteria about minutes