1. DNA

2. Nucleic Acids
What are the types of Nucleic Acids?

3. Nucleic Acids Types of Nucleic Acids: DNA (deoxyribonucleic acid)
RNA (ribonucleic acid)

4. Nucleic Acids Types of Nucleic Acids: DNA (deoxyribonucleic acid)
RNA (ribonucleic acid)
mRNA (messenger)
tRNA (transfer)
rRNA (ribosomal)

5. Nucleic Acids
What are the building blocks of nucleic acids?

6. Nucleic Acids
Building blocks of nucleic acids:
Nucleotides

7. Nucleic Acids Building blocks of nucleic acids: Nucleotides: Adenine
Thymine
Guanine
Cytosine
Uracil

8. Nucleic Acids
How would you recognize a nucleotide?

9. Nucleic Acids
How would you recognize a nucleotide?

10. Nucleic Acids
How do DNA and RNA compare?

11. Nucleic Acids

12. DNA Structure

13. DNA Structure

14. DNA Structure

15. DNA Structure
Double-stranded

16. DNA Structure Double-stranded
Covalent bonds between phosphate and sugar

17. DNA Structure Double-stranded
Covalent bonds between phosphate and sugar
Two strands held together by hydrogen bonding between complimentary base pairs

18. DNA Structure
Described as having two antiparallel strands (aligned in opposite directions)

19. DNA Structure

20. DNA Structure

21. DNA Replication

22. DNA Replication
DNA must make copies of itself to prepare for cell division

23. DNA Replication
DNA must make copies of itself to prepare for cell division during Synthesis Phase of Interphase

24. DNA Replication
DNA must make copies of itself to prepare for cell division during Synthesis Phase of Interphase
Occurs in nucleus

25. DNA Replication
DNA must make copies of itself to prepare for cell division during Synthesis Phase of Interphase
Occurs in nucleus with the presence of
Enzymes (helicase and DNA polymerases)

26. DNA Replication
DNA must make copies of itself to prepare for cell division during Synthesis Phase of mitosis
Occurs in nucleus with the presence of
Enzymes (helicase and DNA polymerases)
Free nucleotides

27. DNA Replication
Step 1:
Helicase initiates the separation of double-stranded DNA into two single strands

28. DNA Replication
Step 1:
Helicase initiates the separation of double-stranded DNA into two single strands by breaking the hydrogen bonds between base pairs.

29. DNA Replication

30. DNA Replication
Now unpaired nucleotides are a template.

31. DNA Replication
Step 2:
A free-floating nucleotide finds a partner on one opened strand at one end

32. DNA Replication
Step 2:
A free-floating nucleotide finds a partner on one opened strand at one end and then a second nucleotide comes in and joins the first, etc.

33. DNA Replication
Step 2:
A free-floating nucleotide finds a partner on one opened strand at one end and then a second nucleotide comes in and joins the first, etc.
DNA polymerase catalyzes the formation of a covalent bond between the two nucleotides.

34. DNA Replication

35. DNA Replication
Step 3:
Other DNA polymerases proofread each nucleotide against the template and make corrections if needed.

36. DNA Replication
Step 3:
Other DNA polymerases proofread each nucleotide against the template and make corrections if needed.
Before proofreading error rate:
1 in 100,000
After proofreading error rate:
1 in 10,000,000,000 (ten billion)

37. DNA Replication
New strands are identical to one another… why?

38. DNA Replication
New strands are identical to one another because of complementary base pairing

39. DNA Replication
Described as a “semiconservative” process

40. DNA Replication
Described as a “semiconservative” process because DNA after replication consists of one “old” and one “new” strand.