1. Nucleotides and Nucleic Acids
DNA and RNA

2. Lesson Learning Outcomes
Upon completion of this lecture, students should be able to:
understand the properties of nucleotides and nucleic acids
recognize DNA and RNA

3. Essential Question What are the structures of the nucleotides?
How are nucleotides joined together to form nucleic acids?
How is information stored in nucleic acids?
What are the biological functions of nucleotides and nucleic acids?

4. Level of structure in nucleic acids
In proteins – primary, secondary, tertiary and quaternary
Nucleic acids are viewed is the same way
Primary structure: order of bases in polynucleotide
Secondary structure: 3D conformation of the backbone
Tertiary structure: supercoiling of the molecule

6. What are nucleic acids?
Nucleic acids are large biological molecules, essential for all known forms of life. 
Nucleic acids, which include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), are made from monomers known as nucleotides linked in a chain through phosphodiester bonds.
In biological systems, they serves as information-carrying molecules or, in the case of some RNA molecules are catalysts.

7. What are nucleotides?
Nucleotides are organic molecules that serve as the monomers, or subunits, of nucleic acids like DNA and RNA.
The building blocks of nucleic acids
Nucleotides are composed of
a nitrogenous base,
a five-carbon sugar (ribose or deoxyribose),
and at least one phosphate group.

9. What is the Structure and Chemistry of Nitrogenous Bases?
Pyrimidines
Cytosine (DNA, RNA)
Uracil (RNA)
Thymine (DNA)
Purines
Adenine (DNA, RNA)
Guanine (DNA, RNA)

10. DNA and RNA

12. Why is DNA 2'-deoxy and RNA is not?
DNA & RNA Differences?
Why is DNA 2'-deoxy and RNA is not?
Vicinal -OH groups (2' and 3') in RNA make it more susceptible to hydrolysis
DNA, lacking 2'-OH is more stable
This makes sense - the genetic material must be more stable
RNA is designed to be used and then broken down

13. What Are the Different Classes of Nucleic Acids?
DNA - one type, one purpose
RNA - 3 (or 4) types, 3 (or 4) purposes
ribosomal RNA - the basis of structure and function of ribosomes
messenger RNA - carries the message
transfer RNA - carries the amino acids

14. Hydrolysis of Nucleic Acids
RNA is resistant to dilute acid
RNA is hydrolyzed by dilute base
DNA is depurinated by dilute acid
DNA is not susceptible to base

15. Functions of Nucleotides
Nucleoside 5'-triphosphates are carriers of energy
Bases serve as recognition units
Cyclic nucleotides are signal molecules and regulators of cellular metabolism and reproduction
ATP is central to energy metabolism
GTP drives protein synthesis
CTP drives lipid synthesis
UTP drives carbohydrate metabolism

17. How does nucleotide forms nucleic acids?
Nucleotides join together through phosphodiester linkages between the 5' and 3' carbon atoms to form nucleic acids.
The 3' -OH of the sugar group forms a bond with one of the negatively charged oxygen of the phosphate group attached to the 5' carbon of another sugar.
When many of these nucleotide subunits combine, the result is the large single-stranded polynucleotide or nucleic acid, DNA 

19. Nucleic acid polymers
Polymers linked 3' to 5' by phosphodiester bridges
Ribonucleic acid and deoxyribonucleic acid
Know the shorthand notations
Sequence is always read 5' to 3'
Eg: 5’-CTTAGATACGTTGCCAGG-3’
In terms of genetic information, this corresponds to "N to C" in proteins

21. The DNA Double Helix Stabilized by hydrogen bonds!
"Base pairs" arise from hydrogen bonds
Erwin Chargaff had the pairing data, but didn't understand its implications
Rosalind Franklin's X-ray fiber diffraction data was crucial
Francis Crick knew it was a helix
James Watson figured out the H bonds

22. Structure of DNA
Double helix – James Watson and Francis Crick (1953)

25. End of lecture today. Please read up Campbell pg. 215-231