11. Nucleic Acids

1. 11. Nucleic Acids • Nucleotides • DNA – nucleotide polymers • RNA (transcription) • Protein Synthesis (the Genetic Code) • Mutations • GMOs

2. 11. Nucleic Acids DNA is a polymer of 4 molecules referred to as dexoyribonucleotides ….. Each dexoyribonucleotide contains ….. 1. 1 of 4/5 bases referred to by letters A, G, C, T (U) 2. The sugar 2-deoxy ribose 3. 1-3 phosphate groups attached to C #5 by phosphate ester bonds

3. 11. Nucleic Acids DNA is a polymer of dexoyribonucleotides ….. Each dexoyribonucleotide contains ….. The sugar 2-deoxy ribose RNA 3. 1-3 phosphate groups attached to C #5′ by phosphate ester bonds DNA

4. 11. Nucleic Acids DNA is a polymer of dexoyribonucleotides ….. Each dexoyribonucleotide contains ….. 1. 1 of 4 bases referred to by letters A, G, C, T U is found in RNA only The bases contain the information content of DNA/RNA determined by their ability to form H-bonds with each other.

5. Base Pairs are formed by H-bonds between bases of DNA/RNA Base pairs must have …. purine + pyrimidine GC or AT/AU C T U donor acceptor acceptor acceptor donor donor acceptor acceptor acceptor A G donor acceptor acceptor donor none donor

6. Naming Nucleotides

7. Naming Nucleotides deoxyadenosine triphosphate - dATP Adenosine triphosphate - ATP

8. Base Pairs are formed by H-bonds between bases of DNA/RNA Base pairs must have …. purine + pyrimidine GC or AT/AU C T U donor acceptor acceptor acceptor donor donor acceptor acceptor acceptor A G donor acceptor acceptor donor none donor

9. Replication Copying DNA molecules (entire chromosomes) occurs every time a cell divides (mitosis) DNA (chromosome) – 1 chromosome contains many genes mitosis DNA mitosis – Makes two identical cells containing ‘nearly’ exact replica of DNA. These cells have the same set of instructions for making proteins. Following these instructions dependent on environment. DNA is not destiny (100%)

10. Replication Copying DNA molecules (entire chromosomes) occurs every time a cell divides (mitosis) Replication dATP dGTP dCTP dTTP } → DNA + nPPi DNA template strand

11. G S P 3 5 C S P P-P-P C S P T S P G S P A S P A S P P-P-P A S P T S P T S P 5 3

12. DNA forms a double helix using H-bonds Base pairs must have …. purine + pyrimidine GC or AT/AU

13. Structure Gene Expression Making proteins from DNA genes transcription + translation DNA (gene) – 1 chromosome contains many genes Transcription makes RNA using information in DNA mRNA Protein sequence YMGCFTSSGLIVVEHY... Translation makes proteins using information In mRNA Function

14. The Genetic Code Table The Genetic Code Table indicates how 3 consecutive bases in mRNA can instruct the cell which amino acid to insert into a growing polypeptide chain.

15. Sources of Mutations • Sometimes when DNA replicates, errors occur. This is a spontaneous mutation. • Environmental agents that produce mutations in DNA are mutagens: many mutagens are carcinogens. • Viruses can also cause mutations. • One common chemical mutagen is sodium nitrite (NaNO2), a preservative in processed meats. In the presence of amines, sodium nitrite forms nitrosamines, which assist in the conversion of cytosine into uracil. • If a mutation occurs in a somatic cell (any cell type other than egg or sperm), it affects only the individual organism and can cause conditions like cancer. • Mutations that occur in germ cells (sperm or egg cells) can be passed on to future generations. Germ cell mutations cause genetic diseases. More than 4,000 genetic diseases have been identified.

17. GMO Genetically Modified Organism Move gene from one organism into another essentially a cut/past job Examples human insulin is now made in bacteria previously isolated from cows/pigs bT corn – resistant to insects Bacterial pesticide gene inserted into corn DNA Cystic Fibrosis Missing Cl- transporter gene inserted into lung cells Uses disabled virus to insert DNA

18. Structure PROTEINS Replication makes DNA copies when cells divide Polymers of Amino Acids DNA (gene) Transcription makes RNA using information in DNA mRNA Protein sequence YMGCFTSSGLIVVEHY... Translation makes proteins using information In mRNA Function

19. Replication dATP dGTP dCTP dTTP } DNA + nPPi

20. DNA forms a double helix using H-bonds Base pairs must have …. purine + pyrimidine GC or AT/AU

21. The Genetic Code Table The Genetic Code Table indicates how 3 consecutive bases in mRNA can instruct the cell which amino acid to insert into a growing polypeptide chain.

22. Sources of Mutations • Sometimes when DNA replicates, errors occur. This is a spontaneous mutation. • Environmental agents that produce mutations in DNA are mutagens: many mutagens are carcinogens. • Viruses can also cause mutations. • One common chemical mutagen is sodium nitrite (NaNO2), a preservative in processed meats. In the presence of amines, sodium nitrite forms nitrosamines, which assist in the conversion of cytosine into uracil. • If a mutation occurs in a somatic cell (any cell type other than egg or sperm), it affects only the individual organism and can cause conditions like cancer. • Mutations that occur in germ cells (sperm or egg cells) can be passed on to future generations. Germ cell mutations cause genetic diseases. More than 4,000 genetic diseases have been identified.

24. GMO Genetically Modified Organism Move gene from one organism into another essentially a cut/past job Examples human insulin is now made in bacteria previously isolated from cows/pigs bT corn – resistant to insects Bacterial pesticide gene inserted into corn DNA Cystic Fibrosis Missing Cl- transporter gene inserted into lung cells Uses disabled virus to insert DNA