For each of the reactions in Problem 1, identify the oxidizing agent and the reducing agent.
For each reaction, identify the substance being oxidized and the substance being reduced.
(a) 2 Sr(s) + O2(g) → 2 SrO(s)
(b) Ca(s) + Cl2(g) → CaCl2(s)
(c) Ni2+(aq) + Mg(s) → Mg2+ (aq) + Ni(s)
Chapter 6 Proteins Overview of Protein - Body is made up of thousands of proteins - Contains nitrogen, carbon, hydrogen, and oxygen - General functions • Regulates and maintains body functions • Provides essential form of nitrogen (in the form of amino acids) Proteins - In the developed world: • Diet is typically rich in protein - In the developing world: • Protein is a deficiency is an issue • Important to focus on protein in diet planning - Aside from water, protein makes up the major part of the lean body tissue - About 17% of body weight Protein Structure - Amino acids are the building blocks of proteins - Amino acids contain nitrogen bonded to carbon • makes them unique from carbohydrates and fats AminoAcids - The proteins in our bodies are made up of 20 different amino acids • 9 are essentials • Some are limiting • 11 are nonessential • New category • Conditionally or acquired indispensable • Infants or disease states AminoAcid Structure - Central carbon - Acid group - Amino group - Side group - Hydrogen - Side group for each different amino acid is different • This gives each amino acid its own characteristics Peptide Bond - Amino acids are connected together by a peptide bond - 2 amino acids-dipeptide, 3 amino acids - tripeptide, etc. - Many amino acids-polypeptide - Some proteins contain multiple polypeptide chains Protein Structure - The sequence of amino acids is called the protein primary structure - Primary structure leads to the protein higher order structure - The higher order structure causes the protein to get into a specific shape (native conformation) - This shape is necessary for the protein to work properly Disruption of Normal Structure - Denaturation • Heat • Strong acids • Bases • Heavy metals - Protein unfolds - Can’t work properly Protein Primary Structure - The protein’s primary structure is determined by the genes (DNA). DNAis kept in the cell’s nucleus - The information of the protein’s primary structure gets transcribed into messenger RNA (mRNA) - mRNAleaves the nucleus and goes to the ribosome (rough ER) where the protein gets translated (made) Protein Synthesis - DNAcontains coded instructions - Copies of codes • transferred to the cytoplasm (via mRNA) - Amino acids added one at a time • With aid of transfer RNA(tRNA) - Requires energy Central Dogma of Biology DNA<> RNA> Protein How to Change Protein Structure - Genetic alterations - Can change the protein’s primary structure - Sometimes this is no big deal - Sometimes it is • It can lead to genetic diseases Sickle CellAnemia - Asingle base substitution • causes one amino acid to be changed in the polypeptide of the hemoglobin protein - Alters the higher order structure of the protein - The protein doesn't work as efficiently - Hemoglobin binds oxygen in red blood cells - With sickle cell anemia, RBC become sickle shapes instead of biconcave Digestion of Proteins - Pre-digestion—cooking • heat denatures proteins, softens food - Digestion begins in stomach 1.Acid (HCL) denatures proteins 2. Pepsin (enzyme) breaks peptide bonds of proteins resulting in protein fragments - Pepsin released by cells in stomach & activates by the acidic environment - What controls pepsin/stomach acid • gastrin: hormone • released in response to think about food, chewing, and digesting food - In the stomach is partially digested protein and other nutrients—chyme - gluten:protein (wheat), makes dough elasticity Movement to SI - Release of CCK (hormone)—chyme stimulates - CCK causes pancreas to release proteolytic enzymes (tripsin,chymotrypsin) - pepsin inactivates (elevated PH) - several peptidases (2-3 amino acid in length) & free amino acids absorbed by active transport - any intracellular peptides digested by enzymes within cells AminoAcidAbsorption - Taken up by capillaries & taken to the liver via the portal vein - liver • amino acids used as building blocks to make liver proteins • broken down for energy • released into blood • converted to nonessential amino acids, glucose/fat Gluten Sensitivity: Celiac Disease - incomplete gluten breakdown in SI leaving small peptides & amino acids - Celiac disease, inflammatory response to small peptides & amino acids - Autoimmune response, genetic predisposition - Prevalence in US is 1 in 133 - In people with related symptoms: 1 in 56 Infant Digestion of Proteins - Up to 4-5 months of age • GI tract is somewhat permeable to small proteins (whole proteins can be absorbed) • If breasted, this allows antibodies to be passed from mother to baby - Recommendation: • waiting until infant is 6-12 mo. old before introducing allergy foods Functions of Proteins in body 1. Producing vital body structures - Body is in a state of constant protein turnover • producing proteins and disassembling proteins - what happens with protein inadequacy • protein production slows down • muscles, blood protein, vital organs decrease in size—brain resists 2. Maintaining Fluid Balance - blood proteins attract fluids - What happens with protein inadequacy • fluid shifts into tissues—edema 3. Contributing to acid-base balance - act as buffers—maintain PH within narrow range • keeps blood slightly alkaline 4. Forming hormones/enzymes - hormones: communicate between cells - enzymes: catalyzes reaction in cells 5. Transport and signaling receptors - Transport: bring nutrients into cells - Signaling receptors: communication in cells 6. Contributing to immune function - antibodies production - What happens with protein inadequacy • decrease in immune function 7. Providing energy - When needed • prolonged exercise • calorie restriction - cells use primarily fats and CHO - Why its efficient • it wastes calories to metabolize amino acids for energy 8. Forming glucose - amino acids can be converted to glucose • when glucose is low - What happens with starvation muscle wasting and edema results from protein breakdown • - glycogenic amino acids - nonessential/essential amino acids 9. Contributing to Satiety - proteins provide highest feeling of satisfaction after eating - may contribute to calorie control during weight loss AminoAcids—fate in cells - breakdown results in release of ammonia Protein Need - If you aren't growing - only need enough protein to replace what they lose daily - What are you replacing - normal protein breakdown (protein turnover) - goal is protein balance Protein RDA - Western Diet—70% of dietary protein typically comes from animal sources - water packed tuna=most nutrient dense - Top 5: beef, poultry, milk, white bread, cheese Problem with Increased Protein Diet - typical source of increased protein diet • animal meat - consequence: • likely to be low in fiber, vitamins, phytochemical • high in saturated fat & cholesterol - Red meat (processed) linked with colon cancer - Increased diet associated with calcium losses in urine - Vegetarian: person who abstains from consumption of meat - Semi-vegetarian: similar to a vegetarian but may consume fish or poultry, or something other than meats - Vegan Vegan Diet - complementary proteins - Nutrient Deficiency concerns • Vitamin B12 • Iron Zinc • • Calcium • Omega 3-fatty acid Alternates to typical Increase protein diet - animal proteins tend to be complete proteins • contains all essential amino acids - plant proteins tend to be incomplete proteins low in one or more essential amino acids • Plant Sources - Nuts: grow on trees - Seeds: vegetables/flowering - Legumes: pods that contain single row of seeds Vegetarian Diets - grains/nuts low in amino acid lycines - veggies/legumes low in methionine - Complimentary proteins—2/more proteins to compensate for deficiencies in essential amino acids content of each protein Complete Plant Protein - quinoa: grain like crop - amaranth: seeds ground into flour, leafy greens - soybeans - buckwheat: not a wheat (rhubarb), grain ground into flour (ex. soba noodles) Protein Consumption - Issues • gluten sensitivity • other Food Protein inAllergies - immune system mistakes food protein for harmful invaders - 8 foods account for 90% of food related allergies; soy, peanuts, tree nuts, wheat, milk, eggs, fish and shellfish - Reactions range from mild to fatal - Introducing allergenic foods early may prevent allergies Protein-Calorie Malnutrition - In the developed world • diet typically rich in world • protein deficiency is issue • important to focus on protein in diet planning - somewhat rare in developed countries • seen in certain populations - In developing countries • stunts growth • increased risk of infection Protein-Energy Malnutrition - Marasmus: starvation/insufficient protein and calorie - Kwashiorkor: marginal amount of calorie and insufficient protein - diseases commonly found inAfrica Protein-Energy Malnutrition in US - Hospital Patients - Long term care residents - community dwelling adults - dialysis patients ALL COMMON: older adults > 65 y/o Chapter 8 Vitamins Vitamins - Definiton: organic substances needed in only small amounts for the proper function of our body • essential • non-caloric • Don’t get energy but work together with enzymes to help use the energy Criteria to be classified as a vitamin - The body is unable to synthesize enough of the compound to maintain health - Absence of the compound from the diet for a defined period produces deficiency symptoms - Can be reversed when the compound is resupplied Vitamin classification - Acompound does not qualify as a vitamin merely because the body can not make it Megadoses of Vitamins - Megadose: • Beyond estimates of needs • Or not in a balanced diet • 2-10 times the normal human needs - Increased risk for toxicity symptoms • Proven useful in treating several non-deficiency diseases Niacin and cholesterol • -Issues with megadoses • Over-supplementation can lead to vitamin levels building up over time • Why Vitamins can be stored within the body • • Which vitamins have the potential for reaching toxic levels Fat soluble vitamins – especially vitaminA Vitamin Preservation - The riper the food the more the vitamins - Vitamins lost from time picked to consumed • Locally grown food is likely to have more vitamins Best to eat as soon as possible after harvest • - Water soluble vitamins destroyed by improper storage or excessive cooking • Heat, light, air, cooking in water, alkalinity - Fresh is better than frozen (as close to harvest date and grown closer to you is even better) How to preserve vitamins in foods - Freezing – best method - Blanching – also works Destroys enzymes that degrade vitamins (heat denatures proteins) • • Put it in boiling water for a few seconds and then freeze ▯ Two classes of vitamins 1. Fat-soluble vitamins –A, D, E, and K - - Absorbed in chylomicrons - Stored in liver and fatty tissue Not readily excreted - 2. Water soluble vitamins – C and B vitamins - Absorbed in capillaries - In general, not stored very well in the body Excess (because it is not stored well) excreted in urine - • If you want to take a lot, then you should space out when you’re taking it VitaminA(Retinoids) and Carotenoids Almost all is stored in the liver - - Deficiency or toxicity can cause severe problems • Narrow range of optimal intake - Retinoids Three active forms of vitaminA(preformed): • - Retinol - Retinal - Retinoic acid Exist only in animal products • - Carotenoids • Contained in plant pigments - Phytochemicals – polyphenols By consuming fruits and vegetables you are getting all of the polyphenols in this large class • - Principle pigments for red, orange, yellow, and green colored fruits and vegetables - Some are precursors to vitaminA • Can be turned into vitaminA: pro-vitamin - Beta-carotene • Carotenoid that can be sufficiently absorbed and converted to retinol • Carrots have a lot of beta-carotene Functions of VitaminAand Carotenoids 1. Health of Epithelial Cells and Immune Function - Maintains health of epithelial cells that line the internal and external surfaces • Lungs, intestines, stomach, vagina, urinary tract, bladder, eyes, and skin - Healthy epithelial tissues serve as important barriers to infection 2. Vision - Night blindness: vitaminAdeficiency disorder that results in loss of ability to see under low-light conditions - VitaminAis important for light-dark vision and color vision • And carotenoids are important for vision • Retina consists of rods and cones • Rods detect black and white, night vision Cones respond for color vision • 3. Carotenoids for Vision - Lutein and zeaxanthin in high concentrations in retina • Found in green leafy vegetables Help prevent macular degeneration • • The central focus of your sight is degenerated so you cannot see the center of what you are looking at • Food sources may help decrease risk of cataracts 4. Cardiovascular Disease Prevention - Carotenoids may decrease risk by preventing oxidation of LDL - Recommendation to consume 5 servings per day of fruits and vegetables 5. Growth, Development, and Reproduction - VitaminAbinds to receptors on DNAto increase synthesis or proteins required for growth - Important for the differentiation and maturation of cells in early fetal growth - Deficiency can cause stunted growth in children 6. Cancer Prevention - Potential benefits but also potential risks • Lower risk of skin, lung, bladder and breast cancers - Megadose supplements pose potential risk for toxicity (enough toxicity can cause cancer) Supplementation not recommended • - Carotenoids • Decrease risk of lung and oral cancers, prostate cancer in men VitaminADeficiency - leading cause of blindness worldwide - eye cells affected • inability to adjust to dim light, causes night blindness - Xerophthalmia: hardening of the cornea, drying of surface of eye and results in blindness. - Risk— NorthAmericans are low risk • TypicalAmerican diet contain preformed VitaminA • Worldwide 1/3 of children suffer - Attempts to reduce problem: 1. Promote breast feeding 2. VitaminAmegadose 2x a year 3. Fortification of sugar/margarine Getting Enough Carotenoids & VitaminA - Preformed VitaminA • Liver, fish oils, fortified milk, butter, yogurt, eggs - Carotenoids • Dark green/yellow-orange veggies • cooking improves bioavailability - RDAexpressed in retinol activity equivalents • Takes into account both preformed and carotenoid sources - typicalAmerican diets sufficient • Supplementation unnecessary for most people Avoiding too much - excess links to birthday defects and liver toxicity • Preformed vitaminA - carotenoids in large amounts do not cause toxic effects • Hypercarotinemia: skin turns yellow orange particularly hands and soles • disappears when intake decreases Vitamin D fat soluble - not just a vitamin but also hormone - Require skin, liver, and kidneys - Body can make vitamin D when exposed to UVB light - Exposure time depends on skin color, age, time of the day, season, location Functions of Vitamin D - helps regulate blood calcium levels and bone metabolism (works with paratynoid hormone) • Helps regulate calcium and phosphorus absorption from intestine • Regulates deposition of calcium in bone • Regulates calcium excretion from kidney - helps in development and can decrease risk of cancer and skin, colon, prostate, ovary, breasts Deficiency of vitamin D - in children causes rickets • Bow legs, and large head, joints, rib cage, deformed pelvis - adults causing Osteomalacia • Softening of bones • Leads to fracture of hips and other bones Vitamin D toxicity - UL-50 micrograms per day - Too much can cause calcium deposits and soft tissues - Can't develop vitamin D toxicity because of too much sunlight Vitamin D foods - fatty fish, fortified milk, yogurt, some breakfast cereal Vitamin E fat soluble - Family of compounds called Tocopherols - Alpha Tocopherol: main form in body - Gamma Tocopherol: foods - Acts as a fat soluble antioxidant - Resides in cell membrane Vitamin E antioxidant rule - oxidizing agent seeking electrons - Example: double bonds of unsaturated fatty acid and phospholipids - Oxidizing agents can create free radicals - As an antioxidant, vitamin E has electrons it can get up as agents - Result: protects compounds of cell (phospholipids) Deficiency of vitamin E - cause cell membrane to break down - Particularly true in RBC, breaking of RBC is called hemolysis • leads to hemolytic anemia - premature infants particularly at risk - smokers Vitamin E toxicity - UL-1000 micrograms per day - Increased doses can interfere with clotting mechanisms and body, leading to hemorrhage - Thus, people at risk are individually taking anticoagulants, high doses of aspirin, or are deficient in vitamin K Vitamin E and foods - plant oils, ready to eat cereals, dry roasted sunflower seeds and almonds, some fruits and vegetables Vitamin K - vital for blood clotting - K in vitamin K comes from danish spelling of coagulation - Vitamin K activates proteins present in bone, muscle, and kidneys to give calcium binding ability to those organs - Poor vitamin K intake is associated with hip fractures in woman - 10% of K is created by bacteria in GI tract - Babies routinely provided with vitamin K supplement at birth...