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Biology 20

Biology 20. Chp . 8.1a pg. 242-245. Chapter 8: Nutrients, Enzymes, and the Digestive System. What are the essential nutrients that must be in your diet? Protein, fat, carbohydrates, vitamins and water Which nutrients are digested? Proteins, lipids, and carbohydrates

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Biology 20

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  1. Biology 20 Chp. 8.1a pg. 242-245

  2. Chapter 8: Nutrients, Enzymes, and the Digestive System • What are the essential nutrients that must be in your diet? • Protein, fat, carbohydrates, vitamins and water • Which nutrients are digested? • Proteins, lipids, and carbohydrates • When digested, what do these nutrients become? • Proteins – amino acids • Fats – fatty acids and glycerol • Polysaccharides – simple sugars

  3. The Canadian Food Guide to Healthy Living • Gives recommendations upon what to eat. • The goals of the recommendations: • Meet the needs for vitamins, minerals and other nutrients. • Reduce the risk of obesity, type 2 diabetes, heart disease, some cancers, & osteoporosis. • Contribute to your overall health and vitality

  4. What’s the most important?

  5. The Canadian Food Guide to Healthy Living • Gives recommendations upon what to eat. • Serving recommendations for a young adult • 7 vegetable and fruit • 6 grain products • 2 Milk and alternatives • 2 meat and alternatives • 2 to 3 tablespoons of unsaturated oils and fats

  6. Elemental Carbon: • Carbon forms covalent bonds with many elements • when found in long chains, provides the structural component for all living things. • inorganic compounds  do NOT contain carbon • organic molecules = compounds containing carbon • Therefore, organicchemistry = the chemistry of carbon compounds. • The wide variety of carbon compounds found in nature can be classified in to different types.

  7. The chemicals of living things:Types of Organic Molecules

  8. Carbohydrates Uses: • FuelCarbohydrates are the MOST important source of energy for the human body. • Carbohydrates are classified into 3 main groups, according to their sugar units. • Monosaccharides = simplest sugars • consists of a single sugar unit • Examples: • Fructose= a plant sugar, common in fruits • Glucose = found in human blood • Deoxyribose = part of the DNA molecule • Ribose = part of the RNA molecule

  9. 3 Common simple sugars: C6H12O6 Note: The previous 3 compounds are isomers, for they have the SAME chemical formulas, but have DIFFERENT structural arrangements.

  10. Forming molecules of Sugar • Dehydration synthesis: (pg. 244 fig.3) • The process by which large molecules are formed by the removal of water from 2 smaller molecules • Hydrolysis: • The process by which large molecules are split into smaller molecules by the addition of water

  11. Disaccharides = 2 sugar units combined. • any of the monosaccharides may be combines in pairs of different arrangements. • The diagram below shows 3 common disaccharides and the monosaccharide components which make them up.

  12. The diagram below shows 3 common disaccharides and the monosaccharide components which make them up. Glucose Fructose = + Sucrose = + Lactose = + Maltose Galactose glucose glucose glucose Honey gets its sweetness from sucrose.

  13. Structural Formula of Maltose Note: All of the above disaccharides are easily digested, crystalline, sweet, and are soluble.Sugars added to food products for sweetness are usually disaccharides GLUCOSE GLUCOSE

  14. Polysaccharides = Many monosaccharide units combined. = large complex molecules Examples: • StarchCarbohydrate storage for plants • Cellulose (products of photosynthesis) • Glycogen = Carbohydrate storage for animals The key structural difference of polysaccharides, like starch and cellulose, is their bonding patterns. {

  15. Starch • highly branched • can be completely broken down to simple glucose units by enzymes in human digestive tract • is our most efficient source of fuel, for starch can be completely broken used without toxic by-products

  16. Cellulose • long straight chains • the bonds between these glucose subunits CANNOT be broken down by the human digestive system because we do not have the enzymes to help us break down such bonds • often referred to as plantfibre, the indigestible material which passes through our intestinal tract unchanged.

  17. Cellulose = Fiber 20-35g/day • Low fiber diets cause constipation, hemorrhoids, diverticular disease, heart problems, and weight gain. • Lowers diabetes and LDL cholesterol • Soluble Fiber: fruits, veggies, legumes, oats, barley • Bacteria in your gut breaks down fiber to make gel-like substance. • Insoluble Fiber: roughage foods with skins, husks and peels; wheat, rice, nuts, cereals • Holds water very well making stool heavier and larger • No less than 3/week; no more than 3/day • Sitting on the toilet for a long time causes straining of the lining of the bowel…bad for later. • Make it healthy: eat regular meals, especially breakfast; drink water; eat fiber.

  18. Cellulose = Fiber 20-35g/day • Colour: not yellow, pale, dark red (bleeding) • Shape: • narrow and pencil thin  colon cancer • Soft, sticks onto the side of toilet  too much oil • Smell: • Stool is made up of undigested food, bacteria, mucus and dead cells. It usually smells bad because of the bacteria and parasites. Fat smells BAD! So can infection and FOOD THAT IS STUCK IN THE COLON FOR TOO LONG! • Constipation: Dry, hard stool poor diet, lack of exercise, certain medications, lack of fluids or various bowel disorders.

  19. Glycogen = “animal starch” • Excess glucose in the blood is removed by the liver and combined to build large, more complex molecules of glycogen. • Glycogen is the major form of carbohydrate storage in the human body. The liver and the muscle cells are the major sites for the storage of glycogen. Therefore, glycogen is readily available for conversion to glucose, when the body needs it for energy.

  20. A molecule of glycogenNotice that it is made entirely of glucose molecules.

  21. Iodine solution reacts with starch to produce a dark purple or black color. 

  22. Homework… • Textbook pg. 245 #1-6 • Day 50 Video Response: watch video, 5-7 points, (hand in paper copy) • Don’t forget about… • Day 49 Video Responses from yesterday

  23. Biology 20 - Lipids chp. 8.1b pg. 246-249

  24. How much fat do you need? # of calories in 1 g of each: Fat – 9 calories Carbohydrate – 4 calories Protein – 4calories Calorie is the approximate amount of energy needed to raise the temperature of one gram of water by one degree Celsius.

  25. Lipids =non-polar compounds which are insoluble in polar compounds like water. = broken down by: either, benzene, acetone, etc. Uses: For humans (& other mammals) • enhance the palatability of meals, for many flavours & aromas are fat soluble substances, insulation against cold. • make up a major portion of the cellmembrane • energystorage in fat cells • are an energy source = a more concentrated fuel than carbohydrates, for it contains much more carbon and less oxygen than carbohydrates.

  26. C, O, H elements are arranged as the organic components – fatty acids & glycerol combined by dehydration synthesis. (produces water) to make TRIGLYCERIDES Fats & Oils are:3fatty acid molecules bonded to 1 molecule of glycerolFats – solid and saturated fatty acidsOils – liquid and unsaturate fatty acids NOTE: -Waxesdo NOT contain glycerol -Triglycerides that are solid at room temp are called fats, liquid ones are called oils.

  27. General Structure: Lipids are: •  composed of the same 3 elements that are found in carbohydrates – oxygen, carbon, & hydrogen.

  28. Fats and oils are classified into main groups, according to the type of fatty acids they contain. • Saturated fats  contain saturated fatty acids These saturated fatty acids: • have no double bonds between carbon atoms • contain all possible hydrogen atoms it can bond too • are found in animal fats • are difficult to break down, since single carbon bonds tend to be stable.

  29. Unsaturated fats  contain unsaturated fatty acids These unsaturated fatty acids: • have at least one double bond between carbon atoms • the carbon atoms with double bonds CAN bond with more hydrogen atoms • are found in plant oils • carbon double bonds tend to be weaker (more reactive), so they are easier to break down

  30. A much higher percentage of a fat molecule can be burned (combined with oxygen) to produce energy. • This is why there are: • 9 calories per gram of fat • 4 calories per gram of carbohydrates • also function as carriers for the fat-soluble vitamins – A, D, E & K • Oils & waxes are produced from lipids

  31. Note: excess fats present in the bloodstream can be removed as an energy source or for storage. • Fat cells however can expand almost indefinitely for the storage of fat. • In an adult, the # of fat cells is fixed, therefore the difference between a fat person and a thin person is the SIZE of the fat cells.

  32. For Plants • Oils & waxes are also produced – to prevent the leaves & stems of plants from drying out. Examples of lipids: • FATS = Solid @ room temp • OILS = liquid @ room temp • WAXES = solid @ room temp • Long, stable molecules are insoluble in water, making them good for waterproof coating for plant leaves, animal feathers and fur

  33. Homework… • Textbook pg. 247 #7-10 • Day 51 Videos (5-7 points each, paper copy) • Testing for starch… • Study for Quiz 8.1 Thursday!!!

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