1. Biology 12 Nucleic Acids

2. Nucleic Acids • Nucleic acids are acidic molecules that are found in the nucleus of cells • There are two types, both of which are vey large • DNA: Deoxyribonucleic Acid • RNA: Ribonucleic Acid

3. Nucleic Acids • All nucleic acids are composed of units called nucleotides, which are composed of three sub-molecules: • Pentose Sugar (ribose or deoxyribose) • Phosphate • Nitrogen Base (purine or pyrimidine)

4. Nucleic Acids • They are formed by joining their subunits together via dehydration synthesis • Nucleotide + nucleotide + ... = nucleic acid • This is quite a complex process to which we will devote an entire unit to

5. Nucleic Acids • Nitrogen base: purines • Adenine and Guanine • Have two rings • Found in both DNA and RNA Memory Trick: It’s Got 2 Be GAP

6. Uracil Nucleic Acids • Nitrogen base: pyramidines • Cytosine, Thymine, and Uracil • Have only one ring • Cytosine is in both DNA and RNA • Thymine is in DNA only • Uracil is in RNA only Memory Trick: CUT the Pyramid

7. DNA: Deoxyribonucleic Acid • Structure of DNA: • DNA is composed of two complimentary strands of nucleotides • The two strands are joined by hydrogen bonds which form between complimentary nitrogen bases • Adenine with Thymine (A-T or T-A) • They join with 2 hydrogen bonds • Cytosine with Guanine (C-G or G-C) • They join with 3 hydrogen bonds

9. DNA: Deoxyribonucleic Acid • When DNA is first made, it is just two linear strands of nucleotides joined together • Due to internal bonding the DNA molecule then forms into a double helix (twisted ladder)

10. Functions of DNA • Directs and controls all cell activities by making all of the proteins and enzymes • Contains all the genetic information necessary to make one complete organism of very exact specifications

11. RNA: Ribonucleic Acid • RNA is made by DNA • It is not confined to the nucleus, it moves out of the nucleus into the cytoplasm of the cell • It has ribose sugar instead of Deoxyribose • It has no thymines, and uses uracil’s instead • It is single stranded and therefore, no helix is formed • There are 3 types of RNA The function of RNA is to assist DNA in making proteins.

15. ATP: Adenosine Triphosphate • ATP is also thought of as a nucleic acid as it has the same structure as a nucleotide • The only difference is that it has three phosphate groups instead of one • This is the energy source for the body

16. ATP Cellular Respiration • Our mitochondria turn the energy of glucose into ATP • ATP is a great molecule to store energy because it takes a lot of energy to put two phosphate molecules together (both –ve) so when you break that bond a lot of energy is released C6H12O6 + 6O2 -----> 6CO2+ 6H20+ energy (heat and ATP)