1. Nucleic Acids and Protein Synthesis
I love the color selection from MS PowerPoint

2. DNA: Structure
Double Helix: Twisted ladder shape of DNA

3. DNA: Structure Monomer: _____________
5 Carbon Sugar (_________________)
Phosphate
Nitrogenous Base (2 kinds)

4. Types of Nitrogenous Bases
Purines:
Adenine (A)
Guanine (G)
Pyrimidines
Thymine (T)
Cytosine (C)
Uracil (U) – Not in DNA

5. Nucleotide Structure

6. DNA Structure Double stranded molecule (Ladder)
Rungs: Nitrogenous bases
Uprights: Alternating Sugar and Phosphates

7. DNA Structure
Antiparallel: The 2 strands run in opposite directions

8. Antiparallel

9. DNA Structure The bases connect the two strands of DNA
Each base ONLY bonds to a corresponding base
A – T
G – C
NO EXCEPTIONS = Mutations
Practice: AAGTACTAGATTACCG

10. Double Helix Why does the DNA ladder twist into a double helix?
ANSWER: Hydrophobic vs Hydrophilic interactions

11. A DNA Review What are the three components of a nucleotide?
DNA ladder: rungs and uprights
Antiparallel
Hydrogen bonding between bases
Double helix and Hydrophobicity

12. Famous Scientists Chargaff’s Rules (%A = %T, %G = %C)
Rosalind Franklin (X-Ray Crystallography)
DNA = 2 strands that coil around one another

13. Famous Scientists Take 2
Watson and Crick (1953)
3D molecule of DNA (Double Helix)
Hydrogen bonds between purines and pyrimidines

14. DNA and Chromosomes Prokaryotic Cells (No True nucleus)
DNA arranged in a large circle OR
DNA found in small circles (plasmids)

15. Eukaryotic Cells (True Nucleus)
DNA is on several linear chromosomes in the nucleus
Each species has its own unique number of chromosomes
Humans – 46
Fruit fly – 8
Giant Sequoia Tree – 22

16. DNA is huge . . . How can it fit in the nucleus?
DNA winds around protein complex (Histones)

17. How it fits continued…
DNA and Histone complex coil to form a Nucleosome
Nucleosomes coil tighter (Supercoil) to form a chromomome

18. Histones and Evolution
Histones are very conserved throughout among different species
Conserved – similar structure and amino acid sequence due to evolution
WHY???

19. DNA Replication When does it occur? Why does it occur?
How does it occur (5 steps)?
Uncoil
Unzip
Add parts
Recoil
Proof-read

20. DNA Replication Take 2 The process is controlled by many enzymes
Steps in detail:
Uncoil
Unzip
DNA helicase unzips the 2 DNA molecules by breaking the Hydrogen bonds between the bases
Typically begins at a site rich in A’s and T’s. WHY?

21. DNA Bases

22. Result: Replication Fork

23. DNA Replication Add parts
Each strand serves as a template for the construction of a seconds strand of DNA
Problem: The 2 strands are anti-parallel
Solution:
One strand copied continually – Leading strand
One strand copied in segments – Lagging strand

24. DNA Replication Leading strand = 3’  5’
Lagging strand = 3’  5’ but leaves gaps
Gaps = Okasaki Fragments

25. DNA Replication 3. Add Parts
DNA Polymerase begins adding corresponding nucleotides to the template strands
EX) ATTATACG
TAATATGC
When finished, DNA Polymerase comes back and fills in the gaps (Okasaki fragments)

26. DNA Replication 4. DNA Recoiled 5. DNA is proof-read
DNA Polymerase proof-reads the 2 strands of DNA for any mistakes
Result: 2 strands of DNA
 Semi-conservative: Definition?

28. Sex Determination and Sex Linkage
Sex is determined by the 23rd chromosomes
XX =
XY =

29. Chances of Having Male vs Female Child
Hypothetical Sex ratio:
Birth Ratio:
Population Ratio:
Kutztown Ratio:

30. X-Linked Traits
The x chromosome is bigger than the y and therefore holds more genes
Examples:
- Hemophilia
- Red/Green Color-blindness
- Baldness

31. Sex Linked crosses These are all recessive traits (For our purposes)
Females must have two bad copies in order to be infected XX
XXC
XCXC
Males only need one bad copy XY
XCY

32. Morale of this story Who is responsible for a son being bald?
Cross One: Cross a bald man with a homozygous normal woman
Cross Two: Cross a normal man with a woman carrying the bald gene.

33. RNA and Protein Synthesis
RNA (Ribonucleic Acid
Type of Nucleic Acid (3 parts)

34. RNA VS DNA RNA is single stranded
RNA’s sugar is Ribose, not Deoxyribose
RNA uses Uracil (U) as a base rather than Thymine (T)
Uracil connects to Adenine (A)

35. Types of RNA Messenger RNA (mRNA) Ribosomal RNA (rRNA)
Transfer RNA (tRNA)

36. What is the job of RNA
Ribosome