nutrient molecules

1. nutrient molecules

3. carry lots of food on the sled carry little food on the sled the solo arctic adventurer’s debate • lighter • don’t have to eat as much in order to pull the sled • harder to drag • costs more body’s energy to haul • therefore need more food to make up for it

18. Trans-unsaturated fatty acids are commonly found in hydrogenated vegetable oils. Oils are hydrogenated to eliminate the double bonds in the carbon chain in order to improve oxidation stability and to increase melting point. Liquid vegetable oil becomes hardened and remains solid at room temperature. However, during hydrogenation, some unsaturated fatty acids that are normally in the cis configuration are converted to the trans isomers. The resulting trans-fatty acids have long straight carbon chains with properties similar to those of saturated fatty acids. Sources of Trans-Fatty Acids In the past, margarines made with hydrogenated vegetable oil are the major source of trans-fatty acids in Westen diet. However, new processing techniques allow the production of margarines with reduced trans-fatty acids. Currently, commercially baked goods, fast foods and other prepared foods are the dominant sources of trans-fatty acids in our diets. Current estimates of trans-fatty acid intake in developed countries range from 0.5 to 2.6% of energy. A number of studies have been conducted to evaluate the effects of trans-fatty acids on plasma lipids. Results from the various studies are similar. In general, it is agreed that the consumption of trans-fatty acids or hydrogenated fats instead of cis-fatty acids or natural oils led to increases in total blood cholesterol levels but not as much as the consumption of saturated fatty acids. However, unlike saturated fat, trans-fatty acids also led to an increase in LDL cholesterol and a decrease in HDL cholesterol when used. As a result, the net effect of trans-fatty acids on the LDL/HDL cholesterol ratio is approximately double that of saturated fat. Furthermore, the consumption of trans-fatty acids also led to increased plasma triglyceride levels. These changes may increase the risk of coronary diseases. http://www.landfood.ubc.ca/courses/fnh/301/lipid/lipid02.htm

22. 10 positions... 20 choices for each position... • so 20x20x20x...... • 2010 different molecules • and most proteins are thousands of amino acids long...

23. primary structure is the ORDER and NUMBER of amino acids in a simple chain • like beads on a string

24. remember there are different R groups • some R groups attract each other

25. this will cause SIMPLE folds, bends, and bridges (--------)

26. if there is regular, repetitive placement of attractive R groups....

27. the chain might wrap itself up into a coil • note attractions between R groups (------) • looks like a phone cord • this shape is called an ALPHA HELIX

28. these SIMPLE folds, coils, and bridges are called • SECONDARY protein structure

29. here’s how the coils are often shown

30. the coils and crosslinks then take on a complex, 3-dimensional folding pattern • the pattern is VERY SPECIFIC • each bend, kink, coil, and loop is exactly programmed to be in that exact place • this is called the TERTIARY structure (or third degree)

31. tertiary structure • note the complex arrangement of coils, strands, loops

35. Four Levels of Protein Structure • Primary • simple strand of amino acids • differ by the number and sequence of the amino acids • 2. Secondary • simple cross-links or folds • dictated by R-groups on amino acids • 3. Tertiary (TERSH-ee-air-y) • complex 3-dimensional folding • usually make a “globular” shape 4. Quaternary (KWA-ter-nair-y) some tertiaries come together may involve non-protein molecules

36. Four Levels of Protein Structure • Primary • simple strand of amino acids • differ by the number and sequence of the amino acids • 2. Secondary • simple cross-links or folds • dictated by R-groups on amino acids • 3. Tertiary (TERSH-ee-air-y) • complex 3-dimensional folding • usually make a “globular” shape 4. Quaternary (KWA-ter-nair-y) some tertiaries come together may involve non-protein molecules

37. Four Levels of Protein Structure • Primary • simple strand of amino acids • differ by the number and sequence of the amino acids • 2. Secondary • simple cross-links or folds • dictated by R-groups on amino acids • 3. Tertiary (TERSH-ee-air-y) • complex 3-dimensional folding • usually make a “globular” shape 4. Quaternary (KWA-ter-nair-y) some tertiaries come together may involve non-protein molecules

38. Four Levels of Protein Structure • Primary • simple strand of amino acids • differ by the number and sequence of the amino acids • 2. Secondary • simple cross-links or folds • dictated by R-groups on amino acids • 3. Tertiary (TERSH-ee-air-y) • complex 3-dimensional folding • usually make a “globular” shape 4. Quaternary (KWA-ter-nair-y) some tertiaries come together may involve non-protein molecules

39. Four Levels of Protein Structure • Primary • simple strand of amino acids • differ by the number and sequence of the amino acids • 2. Secondary • simple cross-links or folds • dictated by R-groups on amino acids • 3. Tertiary (TERSH-ee-air-y) • complex 3-dimensional folding • usually make a “globular” shape 4. Quaternary (KWA-ter-nair-y) some tertiaries come together may involve non-protein molecules