DNA and RNA

1. DNA and RNA

2. Nucleic Acids • Nucleic acids are made from nucleotide monomers • A nucleotide has 3 groups • Phosphate • Ribose sugar • Nitrogenous base

3. The phosphate and the ribose combine to form a long chain polymer with the nitrogenous base sticking out to the side

4. Fig. 15-21, p. 321

5. There are two types of nucleic acids • DNA – Deoxyribonucleic acid • RNA – Ribonucleic acid

6. There are 5 nitrogenous bases • Adenine (A) • Guanine (G) • Cytosine (C) • Thymine (T) • Uracil (U)

7. DNA and RNA each only use 4 of the 5 bases • DNA uses A, G, T, C • RNA uses A, G, U, C

8. DNA contains the whole genetic code for life within each single cell • RNA codes for a single type of protein • Thus RNA is made from DNA

9. In the late 1850s a monk named Gregor Mendel observed certain traits in plants • He noticed plants could pass along information such as flower color from one generation to the next

10. In the early 1900s chromosomes were found in cells • Chromosomes are structured DNA and only visible when cells are preparing to divide

12. 1953 Watson and Crick determined the base pairing of DNA • A:T • G:C

13. Base pairing led to the discovery of the structure of DNA being a double helix

14. DNA replication • When cells divide the DNA must be replicated so the new cell will also have a copy

15. DNA to protein • DNA contains the code for each protein we need to make • This code is called a “gene” • Each gene codes for a single polypeptide • For humans we have about 40,000 genes • This makes up 20% of our total DNA

16. Fig. 15-24, p. 323

17. Redundancy in protein coding

18. Genetic engineering • Restriction enzymes – cut DNA into smaller fragments • These are naturally occuring enzymes found in bacteria and viruses to protect their DNA from foreign DNA

19. These enzymes cut DNA at specific sites where there is an inverted repeat of DNA bases • CAGCGAATTCTGCACTG • GTCGCTTAAGACGTGAC

20. Every time this sequence occurs in DNA the enzyme will make a cut. • We can use this to our advantage

21. DNA fingerprints • When restriction enzymes are added to a sample of human DNA it cuts the DNA into smaller pieces • DNA has an overall (-) charge

22. A special technique can be used to separate DNA by its charge and size • This is called Gel Electrophoresis

24. By using several different restriction enzymes, each person’s DNA will be cut up into different sized fragments. • This makes up our DNA fingerprint since each person will create a unique set of bands on the gel.

25. Recombinant DNA • Restriction enzymes can also be used to make new strands of DNA

26. This allows us to make bacteria work for us as little protein production factories • Many of the proteins we need to sustain life can be produced by bacteria cheaper than we can synthesize them in a lab

27. Diabetics • Diabetes is a well know problem for many Americans • This disease revolves around the body’s inability to produce insulin • Insulin is a very necessary enzyme that helps get glucose into cells so they can make energy • Without insulin we would die

28. Until the early 80’s diabetics had to use pig insulin • Humulin was produced from bacteria carrying the human insulin gene and marketed in 1983 • Less compatibility problems using Humulin than pig insulin

29. Many other human products are now begin produced by bacteria instead of being harvested from animals • Human Growth Hormone • Bovine Growth Hormone • Epidermal Growth Hormone