Macromolecules, Food and What s in food?

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1 Macromolecules, Food and What s in food? Digestion Protein Lipids (Fat) Macromolecules Many small molecules connect to form Macromolecules Monomers Small Molecules (Building Blocks) Range in size from single sugars to long sugar chains (polysaccharides) Polymers Large Molecules Polysaccharides are longer sugar chains Glycogen is a polysaccharide stored in animal tissue Proteins Polymers constructed from amino acid monomers Polymers long chains of simple sugars

2 Proteins = polymers of amino acids Polypeptides Protein Monomers The millions of different proteins are all formed from just 20 building blocks, called amino acids Amino acids come in 20 Different Flavors! (Lysine, Valine, Tryptophan, Proline, etc.) Lipids (or fats) Functions of proteins Macromolecules that are not soluble in water Body structures Regulate body functions OH Enzymes Hormones Triglycerides Saturated fats have no double bonds The Carbon chain is completely saturated with hydrogens solid at room temperature O Lipids liquid at room temperature HC Steroids Unsaturated fats have at least one double bond Steroids Seldom used for energy Lipids X Hydrophobic or water-fearing large molecules with a four-ring structure Examples cholesterol sex hormones 3 H3C HO a. Cholesterol an integral part of cell membranes responsible for the enormous changes of puberty OH OH O b. Testosterone HO c. Estrogen

3 Why we eat Water Energy (calories) Building blocks Essential nutrients Primarily vitamins and minerals What is a Nutrient? Any substance that the body uses to: provide energy (calories) regulate body processes contribute to cell and body structure Is alcohol a nutrient? Alcohol provides energy (7 Cal/g) But it has no necessary function in the body Toxic when consumed in large amounts What are the 6 types of nutrients? Water is critical for body functions The body is about 70% water Protein Vitamins Minerals Found both inside and outside the cells Functions Helps regulate body temperature Transports nutrients Fats Water Excretes waste products Nutrients supply energy Food as Fuel Protein These nutrients supply energy (calories) to power muscle contraction, maintain body temp and other cell functions Cells Break down food macromolecules in cellular respiration. Generate many molecules of ATP. Fats

4 Energy (Calories) from Nutrients Nutrient Energy Carbohydrate 4 cal/g Protein 4 cal/g Fat 9 cal/g Which is the most energy-rich nutrient? Some nutrients help regulate body processes Vitamins and minerals (the micronutrients) and water Vision Vitamin A Metabolism Iodine is a component of thyroid hormone Iron helps transport O 2 Blood pressure Food as Building Material Nutrients contribute to cell and body structure Proteins, minerals and water provide structure to bone, muscle and other tissues Bone Muscle Primary source of energy for living organisms Simple sugars Table sugar, soft drinks Polysaccharides Long starch molecules How does the body use carbohydrates? Metabolized to provide Energy Primary source of energy for the body and brain Provide Fiber A complex carbohydrate that humans can t digest Why do we need Fats? Dietary fats provide Energy for the body Fat-soluble vitamins (vitamins A, D, E and K) Essential fatty acids (omega-3 and omega-6) Long-term energy storage in adipose tissue

5 Kinds of Fats Cholesterol Saturated Fatty Acids (All Single Bonds C-C) Heighten Heart Disease Risk Unsaturated Fatty Acids (Some Double Bonds C=C) Reduce Heart Disease Risk Trans-Fatty Acids (Hydrogenated) Heighten Heart Disease Risk Not Found Naturally! LDL and HDL cholesterol Protein an all important nutrient HDL or Healthy cholesterol Removes excess cholesterol from cells Protects against heart disease LDL or Lousy cholesterol Transports cholesterol to the cells; sticks to artery walls Contributes to plaque build-up High levels of LDL cholesterol raise the risk of heart disease Helps build and maintain body tissues Main job is to build muscle, bone, skin and hair Regulates body functions Many hormones are proteins Protects you from illness Antibodies are protein Sometimes used for energy Sources: meat, eggs, beans, nuts Essential Amino Acids Must be obtained from the diet the body can t synthesize them. Different foods contain different essential amino acids. The Micronutrients Essential (can t be made by body) Required in small amounts ( micro ) for normal growth and health Vitamins Fat-soluble: A, D, E and K Water-soluble: C, B-vitamins Minerals Calcium, iron, iodine, zinc and others

6 Is alcohol a nutrient? Alcohol provides energy (7 Cal/g) But it has no necessary function in the body Toxic when consumed in large amounts Alcohol - the good, the bad and the ugly People drink to relax, celebrate and socialize Harmful effects Weight gain Damage to the digestive system, heart and liver Puts a healthy pregnancy at risk Alcoholism Obesity Results from regular intake of excess energy Major risk factor for chronic diseases Cardiovascular disease Certain types of cancer Type 2 diabetes Iron is part of hemoglobin, the oxygencarrying protein in red blood cells What is good nutrition? Getting the right nutrients Foods that provide energy Essential nutrients that the body can t make Getting the correct amount of food energy (cal) Basic advice for good nutrition Eat a variety of foods Fruits, vegetables and whole grains Eat less don t overeat Avoid too much junk food Exercise more