1. http://www.ornl.gov/hgmis Gene Expression Defines Cells

2. Recall the Central Dogma DNARNAPROTEIN InfoInfo CarrierFunctional Product

3. http://www.ornl.gov/hgmis All Information is in DNA

4. Principle information molecules in the cell Linear polymer of nucleotides (or bases) Two types Deoxyribonucleic Acid – DNA Information storage in cells Ribonucleic Acid – RNA Information carrier in cells DNA is a Nucleic Acid

5. Three components Nitrogenous Base (A, C, G, T) Ribose Sugar Phosphate Nucleotides in DNA

6. Nucleotide Bases

7. Nucleotide Detail

8. For DNA bases are A, C, G, T Sugar is deoxyribose (no OH at 2’ position) For RNA bases are A, C, G. U Sugar is ribose (OH at 2’ position) DNA and RNA

9. Phosphodiester Links Nucleotides

10. Holds nucleic acid strands together H-bonding between complementary bases This is an interaction that is easily broken A pairs with T (DNA), (A-U for RNA) G pairs with C (both DNA and RNA) Complementary Base Pairing

12. DNA Structure

13. DNA Structure Reveals Copying Mechanism

14. DNA is Transcribed http://commons.wikimedia.org/wiki/Image:DNA_transcription.gif

15. Transcription Initiation http://upload.wikimedia.org/wikipedia/commons/thumb/9/91/Simple_tr anscription_initiation1.svg/721px- Simple_transcription_initiation1.svg.png Promoter with Transcription Factors

16. http://stemcells.nih.gov/StaticResources/info/scireport/images/figurea6.jpg Transcription and Translation

17. Proteins Primary functional molecules of the cell; execute the tasks directed by the genetic material 1. Structural molecules (e.g., hair, fingernails, connective tissue) 2. Transmitting Information between cells (e.g., hormones) 3. Defense against infection (e.g., antibodies) 4. Enzymes (catalyze nearly all biochemical reactions)

18. Building Blocks are Amino Acids 20 different amino acids in proteins Chemical properties of side chains determine function Central carbon atom (C  ) 1.H atom 2.Amino group (NH 3 + ) 3.Carboxyl group (COO - ) 4.R group (side chain)

19. R-group (Side Chain) R -group determines identity, function A.A. are categorized by chemical properties of the side chains 1) Polar (uncharged) = hydrophilic 2) Positively charged (basic) = ionic 3) Negatively charged (acidic) = ionic 4) Nonpolar = hydrophobic

20. Nonpolar Amino Acids The side chains of these a.a. tend to be located in the interior of proteins, where they are not in contact with water.

21. Peptide Bond Links amino acids Amide linkage between  -NH 3 and  -COO - Defines amino (N) terminus and carboxy (C) terminus

22. Protein Structure Polypeptide (protein) chains fold into globular structure Defines cracks and crevices that can interact with other molecules Allows proteins to be enzymes

23. Enzymes Enzymes are catalysts They increase the rate of reactions This allows rapid synthesis and degradation of products in cells

24. Building Proteins -Translation mRNA contains 3 nucleotide codons Each codon specifies an amino acid Triplet codons are decoded by tRNA decoding is base pairing between codon on mRNA and anticodon on tRNA Each tRNA carries a specific amino acid codon-anticodon pairing delivers specific aa to the growing polypeptide chain "protein: synthesis." Online Art. Britannica Student Encyclopædia. 10 Aug. 2008.http://student.britannica.com/eb/art-1692>.

25. http://www.ornl.gov/hgmis Overview of Gene Expression