Chemistry of Life

1. Chemistry of Life G.Burgess 2012

2. In a nut shell • All matter is made of atoms; cells are matter; cells are made of atoms • Atoms have shape • Atoms interact chemically and physically making compounds • The interaction of compounds shapes life • three major compounds found in cells are; proteins, lipids and carbohydrates • Each type differes in composition and shape.

3. Lipids • composed of C,H,and O • (ie. C57H110O6) • Produced by both plants and animals as cell membranes, fats, oils, waxes and steriods. • Used for prompting chemical reactions of homeostasis, protection from environment, and storing excess energy. • Lipids are hydrophobic; they repell water

4. Saturated, Unsaturated and Transfats • Note, both saturated fats and transfats are linear and unsaturated have a bend • Saturated and transfats are solid at room temperature • Unsaturated fats are liquid at room temperature

5. Cell Membrane • Keeps the cell separate from the external environment and regulates materials that are able to enter and leave the cell. • Fluid mosaic model: • Composed of lipids held together by cholesterols, and proteins • Lipids: act as barrier to water • Cholesterols: add strength to lipid membrane • Proteins: enable ions and water soluble materials to enter the cell, give the cell identity and may act as attachment sites for other cells or macromolecules.

6. Phospholipid • Note the polar head and fatty acid tails are connecdted by a glycerol

7. Cell Membrane https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcTD_hYpUl6E5TneNniP9ixk_zYQs_6ioHOB4-auF44dx4ZO6_GZrg, accessed Sept.6 2013. https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQkZmwhsfzPah80ov8CA9T9laWv3UlpMZk2eQbr1NZ_lNA-aL9P, accessed September 6 2013.

8. Carbohydrates • composed of C,H, and O (ratio of 2H to 1O) • Sugars are made of keytones or aldehydes combined with carboxyl groups. • primary source of molecular energy. • produced by plants in the form of simple sugars and polysaccharides. • Simple sugars C6H12O6 are called monosaccharides • Simple sugars; gluose, galactose, fructose • Two simple sugars form a disaccharide more than two molecules joined make a polysaccharide.

9. Glucose, Fructose and Galactose • Note the chemical formula is the same, but the shapes and structures are different

10. Proteins • composed of C, H, O and N • (nitrogen is a necessary element for forming amino acids, the building blocks of proteins) • a single protein may be formed from 100’s of amino acids • two amino acids make a dipeptide; more make up a polypeptide • RNA, DNA and hormones are examples of polypeptides. • The type of polypeptide formed depends on the number and sequence of the amino acids that make it. • there are 20 different amino acid groups. • These acids form the code that controls an organisms basic behavior and appearance.

11. Amino Acid Groups • These are just a few. • Each has a different composition and shape. http://www.healthknot.com/body_protein.html, accessed August 2012

12. RNA, DNA Structure • Note both are made of nitrogen bases • RNA has ribose sugar • DNA has deoxyribose sugar http://www.proprofs.com/flashcards/cardshowall.php?title=exam-5-review, accessed August 2012

13. Transport Mechanisms • Materials need to be transported through out an organism or cell. • Hemoglobin is an example of a transport molecule. It transports oxygen from the lungs to tissues in the body. • Cells use transport molecules to allow materials to cross through the cell membrane. • Either by passive or active transport.

14. Passive transport • Molecules enter a cell without the need for ATP. • Always from area of high concentration to area of low concentration • Diffusion: transport of lipid soluble materials across the cell membrane (ie. Vitamin A, K, alcohols, some metal compounds) • Facilitated transport: transport of water soluble materials with the help of transport proteins.

15. Diffusion • The passing of materials from the fluid environment across the cell membrane to the cytoplasm • Does not require ATP • Materials cross the membrane with out the need of transport proteins

16. Facilitated Transport • Passive transport that moves water soluble materials across the cell membrane • ie. water molecules, glucose, cations, and anions • Why transport Proteins? • Enable the cell to maintain and regain needed chemical components for metabolism and cell function. • Help cell to maintain concentrations of chemicals and water • To get rid of excess materials without interfering with continual cell processes.

17. Channel Protein Channel Proteins: form a hole through which materials may pass.

18. Carrier Protein Carrier proteins: capture molecules and ions, change shape and release materials into cytoplasm

19. Gate Protein Gate proteins: open when signal molecule attaches ‘opening the gate’ to allow materials to pass into the cytoplasm.

20. Cellular Homeostasis and water concentrations • Three basic types of cellular environments; • Isotonic solutions: these solutions have the same or similar amounts of dissolved materials as the cytoplasm of a cell • Hypotonic solutions: have a greater concentration of water than what is present in the cell • Hypertonic solutions: have greater amounts of dissolved materials than what is present inside the cell. • Each of the solutions describe have an effect on the cell’s ability to survive.

21. Cellular Homeostasis and water concentrations • Isotonic Solutions: do not have an effect on a cell, as they mimic the cell’s inner solution. Ie. saline solution for eyes. • Hypotonic Solutions: will cause a cell to enlarge or break. Since the concentration of water is greater outside the cell, the water will flow into the cell until equilibrium is found. • Hypertonic Solutions: will cause a cell to shrink or collapse. Since the environment has a greater concentration of dissolved materials, water from the cell will move to the environment until the environment has the same concentration of water as the cell.

22. Active Transport Proteins • These proteins, called pumps, move molecules and ions against concentration gradients. • They move materials from areas of low concentration to high concentration. • To do this they require ATP. • The Na-K pump (sodium potassium pump) is an example of an active transport protein.

23. Digestion and Synthesis of organic molecules • Digestion refers to the breakdown of organic molecules into smaller/ simpler pieces. • Synthesis refers to the formation or joining of simple organic pieces into larger more complex ones. • These processes are completed by condensation reactions and hydrolysis reactions. • Condensation reaction: dehydration reactions occur when a hydroxyl is removed from one molecule and a hydronium is removed from another as the two molecules form a larger molecule. The combining of hydroxyl and hydronium forms water • Hydrolysis: water is added to a reaction separating the hydronium and hydroxyl forming two smaller molecules. • **Hydroxyl and hydronium groups serve to complete the molecular charges of the smaller molecules.

24. Digestion and Synthesis Processes Condensation Reaction C6H12O6 + C6H12O6 C12H22O11 + H2O Hydrolysis Reaction C12H22O11 + H2O  C6H12O6 + C6H12O6 The body uses these reactions to form needed structural and chemical components.

25. Interesting Links • Robert Horvitz's Work on Cell Death, http://www.dnalc.org/nobel2002.html, Horvitz, B. and M.Hengartner, Gene accessed Feb.2, 2007.