BIOL 203 Final Exam Review PDF

BIOL 203 Final Exam Review Chapter 2 2.2 DRIs Reference values that are estimates of nutrient intakes to be used for planning and assessing diets for healthy people Historical reason: reduce risk of deficiency diseases, which are nowadays rare. Now we worry about chronic diet related diseases Nut...

BIOL 203 Final Exam Review Chapter 2 2.2 DRIs Reference values that are estimates of nutrient intakes to be used for planning and assessing diets for healthy people Historical reason: reduce risk of deficiency diseases, which are nowadays rare. Now we worry about chronic diet related diseases Nutrient intake standards Two groups: 1. EAR, RDA, AI, Ul 2. DRIs for energy and macronutrients targets exclusively carbs, lipids and protein intake EAR: - Deficiency diseases - Estimated average requirement - Average daily intake level of a nutrient to meet the needs of half of the healthy people in a group (life stages, gender…) RDA: - Deficiency diseases - Recommended dietary allowance - Average daily nutrient intake level that meets the needs of 98% of healthy people in a group AI: - Deficiency diseases - Adequate intake - Intake level based on a healthy group of people in a population - AI is higher than the EAR UL: - Supplement use - Tolerable Upper Intake Level - Highest level of usual daily intake likely to be safe Nutrients differ by gender and lifestage. Men have 10 life stages, women have 16 (include pregnancy and lactation periods, where nutrient intake must increase Iron intake for women: 8mg at 13 yrs old, 15mg from 14-50 yrs old, back to 8 mg at 51. During pregnancy: 27mg. 45-65% of energy should come from macronutrients, 20-35% from fat and 10-35% from protein Food Groups Grains, Meats, Milk, Vegetables and Fruit Chapter 3 3.2 Atoms to Compounds 25% of the elements on the periodic table of elements are essential for life Matter is anything that takes up space Smallest unit of matter is the atom Human body is composed of matter representing 23 or more different elements (but trillions of atoms) Planet had 92 elements but near infinite amount of atoms Atoms come together to form chemical bonds in ordered and stable arrangement → molecule Molecules: Oxygen, gas, CO2, water, glucose Molecule has two or more different elements: compounds CO2, H2O, glucose Atoms are composed of protons, neutrons and electrons Core of the atom is made of positivity charged protons and neutrons that carry no change → atomic nucleus Surrounding the nucleus is a cloud patrolled by negatively charged atoms Under normal conditions: equal number electrons and protons → neutral charge All atoms have 2 electrons orbiting the first inner shell (besides H) The second shell varies between 1 and 8 orbiting electrons (valence shell & valence electrons) If there’s a third shell, can carry 1-8 electrons Valence shells are completely filled when they have 8 orbiting electrons (besides H with just 2) Atoms with full valence shells are chemically inert (do not form chemical bonds) Ex: helium, neon, argon Covalent Bonds Atoms with incomplete shells pair up with other atoms to share/transfer electrons → chemical bonds are formed Strongest bond Ionic Bonds Atoms that donate the outer electron to another atom Typically, have less valence electrons so are able to lose their electron to fill the valence shell of another atom to form the bond 3.3 Solutions, Solubility, Enzymes and pH Solution: mixture of 2 or more compounds Solvent: primary component of a solution When water → aqueous solution Solute: lesser component of a solution Electronegativity Atom’s attraction for the electrons in a chemical bond. More electronegative an atoms, more strongly it pulls shared electrons towards itself. Oxygen is very electronegative Polar Molecules Molecules with partial charges created by electronegative atoms Polar molecules interact with other polar molecules to form weak H bonds Solubility of Starch Starch is packed into tight dense granules. Need yo unravel the granules to dissolve starch. Done by heating the water to unfold the starch threads and granules swell and expand. As starch unfolds, it forms an H bond with water. Forms thick mixture. Temperature when starch becomes a gelatinous mixture is called the gelation temperature. Cooking Pasta As heated water cools, the water molecules form H bonds with the starch in the water. Water becomes stuck in the starch (water becomes a thick mixture). If you rinse cooked pasta, you actually rinse of the starch, which is what makes the sauce stick to the pasta. Add potato to boiling water for additional starch content. Enzymes Proteins. Dissolve in solution. Helps you digest food into smaller fragments. Ex: Lactase, without it, lactose intolerance Held together by covalent bonds. 3D shape is because of H bonds, which means enzymes can easily change shape pH pH of saliva: 6.4 pH of stomach: 1 pH of small intestine: 8 As H ion increase, acidity increases (lower pH value) Scale from 0 - 14, with each # increasing on the scale, concentration of H ion decreases 10x 3.4 Digestive System Digest food and deliver nutrients to the cells Tissues Epithelial tissue: - Lining of the entire alimentary canal - Synthesize and secrete enzymes for digestion and absorb nutrients Connective tissue: Muscle Tissue: in the stomach Neural Tissue: Organs Tube from mouth to anus. Inside hollow tube is called the lumen Organs: Mouth → pharynx → esophagus → stomach → small intestine → large intestine → rectum → anus Accessory organs: salivary glands, gallbladder, pancreas, liver Small Intestine Circular folds along the lumen, look like ripples, have villi Each villi has two types of vessels: blood vessels and lymph vessels (lacteal vessel) Villi is made of epithelial cells, with microvilli Maximizes the surface area so nutrients can be maximally and quickly absorbed Old epithelial cells fall off into the chyme and are digested. New cells replace the old ones First sign of malnutrition : diarrhea (can't replace the epithelial cells, can't absorb food) Elimination Waste is removed from the body Substances for excretion end up in the large intestine Large intestine mingles with gut microbes Very little protein, carbs or fat enters the large intestine Microbes feast on fibers Probiotic food contains live bacterial cultures, some thrive in the colon Prebiotic food is typically fiber rich 3.5 Circulatory System Heart acts as pump to keep blood moving through the system Network of blood vessels include: arteries, arterioles, capillaries, venules and veins Red blood = carries oxygenated blood Chapter 4 4.2 Calories Plants pack calories into carbohydrates Through photosynthesis, plants take 6 molecules of CO2 from the air, extract water from the soil and use sun energy to rearrange molecules to make O2 and glucose When you need energy, the cells break down the glucose and release the stored energy Calorie is a unit that measures heat energy calorie : heat energy necessary to raise the temperature of 1g of water 1*C Measure food in kilocalories (Calories) Calorie : heat energy necessary to raise the temperature of 1000g of water 1*C Bomb Calorimeter Measures the energy content of food Insulated container enclosing a steel vat filled with water Immersed in the water Ignition wires ignite the food and the food sample burns C-H bonds are broken, heat energy is released Temperature of the surrounding water heats up. Increase is measured using a thermometer Proteins provide 4 kcal per g Lipids provide 9 kcal per g 4.3 Simple Carbohydrates and Non-nutritive Sweeteners Simple carbohydrates have varying sweetness, provide 4 kcal per g Monosaccharides Glucose, Fructose, Galactose All have the same chemical formula (6 C, 12 H, 6 O) Arrangement of atoms is what differs, which is why they have different degrees of sweetness Fructose: - Sweetest - Found in fruits and honey Glucose: - Middle sweetness - Found in fruits and vegetables Galactose: - Barely detectable sweetness - Found in milk Glucose is the most important. It is the dominant sugar in the body and the dominant energy source for red blood cells and cells of the nervous system Red blood cells (RBC) rely almost exclusively on glucose Disaccharides Pairs of monosaccharides Glucose is always present in the pair Second pair could be fructose, galactose or another glucose Glucose + galactose: Lactose (milk sugar) Glucose + glucose: Maltose (malt sugar) Glucose + fructose: Sucrose (table sugar) If not present in the food we eat, it is a by-product of starch digestion Raw sugar, brown sugar and table sugar are all made of sucrose. Raw sugar and brown sugar are less processed and maintain more minerals and vitamins Corn In the 1970s, the food industry introduced high-fructose corn syrup (HFCS) Microbes, Simple Sugars and Oral Health Bacteria grow and thrive from sugars stuck in the crevices of your teeth Alternative Sweeteners Synthetic compounds that are intensely sweet tasting compared to sugar but supply no energy per serving Artificial sweeteners are made from a molecule of sucrose that has been chemically modified to escape digestion and absorption Exception: Stevia which is a natural herbal sweetener 4.4 Complex Carbohydrates Starch Source Plants store glucose in the form of starch. Starch is then stored in different parts of the plant body for later use. Starch, stored in seeds like grains and legumes, is destined for the developing embryo Vegetables (like tubers) store starch for growing the plant Different in how the starch is stored determines the consistency, texture and flavour Starch Types Amylopectin: - Branched type - Has many free ends si that the enzymes in the small intestine can work faster to digest the glucose, so blood sugar levels rise fast Amylose: - Single linear thread of glucose - Has 2 free ends, therefore takes longer to digest, so blood levels rise slowly Starch Packaging High starch potatoes: best for baking, mashing, frying When cooked, starch granules swell and plant cells separate High-starch variety Best for absorbing milk/butter (mashed potatoes) Low-starch/waxy potatoes: best for salads because they hold shape Glycogen Animal version of starch Break down starch and absorb glucose. This then travels to the liver where its stored in the form of glycogen When cells need glucose for energy, liver breaks down glycogen to release glucose into blood stream Glycogen is stored in muscle tissue When we exercise, muscle cells break down glycogen to release glucose for energy Liver and muscle tissue have limited space for glycogen storage. Rest of glycogen is converted to fat and stored in adipose tissue Fibre: Two Types Soluble & Insoluble Soluble: dissolves and becomes viscous in water Pectin: glue that keeps plant cells together Fermented by the bacteria in the large intestine Become a thick gelatinous solution in the small intestine. High viscosity → slow gastric emptying → reduce obesity risk Insoluble: do not dissolve in water Non viscous Add bulk to stool Helps prevent diverticula 4.5 Digestion and Absorption of Carbs Begins in the oral cavity with salivary amylase. Continues in small intestines with maltase, sucrase, lactase and pancreatic amylase. End product us mostly glucose, some fructose and some galactose Lactose Intolerance Inability to digest lactose completely Do not produce enough lactase (enzyme) Bacteria in large intestine break down lactose and produce gas and acid Young kids produce large amounts of lactase As we age, 70% of people become lactose intolerant 4.6 Carbohydrates and Disease After carb-rich meal, blood glucose levels rise quickly → hyperglycemia (high blood sugar) Pancreas produces insulin Insulin binds to the cells and takes in the glucose If you haven’t eaten in awhile, blood sugar levels decline, so other cells in the pancreas secrete glucagon into the bloodstream = blood glucose homeostasis Diabetes Inability to maintain blood glucose homeostasis Type 1: autoimmune disease Immune system destroys the cells in the pancreas that synthesize insulin Treatment: daily injections and eating meals at specific times Type 2: 90% of people with diabetes have type 2. Caused by high-sugar diet Cells become resistant/less responsive to insulin, so glucose cannot enter the cell Preventable Gestational diabetes: occurs during pregnancy in some women (caused by poor diet) 4.7 Carbohydrates and DRIs RDA of glucose: 130g AMDR for carbs 45-65% of caloric intake Based on 2000 kcal diet, it's about 225 to 325 g of carbs Should come from pulses, fruits and vegetables Chapter 5 5.2 Lipids in Food and in the Body Lipids are necessary for: - Enhancing the flavour and palatability of food - Enhance intestinal absorption of fat-soluble vitamins and phytochemicals - Contribute to satiety (the feeling of being full) Fat Cell - Adipose Cell Fat works like a soft body armor to protect the viscera and bones from breaking when we fall Fat is a type of connective tissue Visceral fat and subcutaneous fat Visceral fat protects the abdominal organs Subcutaneous fat (located below the surface of the skin) helps maintain body heat and cushion the body Extra subcutaneous fat helps us protect the bones as we age Lipids in the Body Lipids are a major source of energy Fat provides 2x more energy than carbs and protein Lipids are the only form of energy stored for prolonged periods of time 5.3 Types of Lipids in Food and in the Body Type of Lipids Lipid family includes fatty acids, triglycerides, phospholipids and cholesterol Building block of lipids: fatty acids Fatty acids form triglycerides (3 fatty acids) and phospholipids (2 fatty acids) Cholesterol: lipid that stands out because lacks fatty acids and not used as energy source Fatty Acids: Length Chain of carbon atoms attached to hydrogen atoms Fatty acids have a methyl group at one end and an acid group on the other Insoluble, non-polar molecules Short chain fatty acids are 2-4 carbons long Medium chain fatty acids are 6-12 carbons long Long chain fatty acids are 14 to 24 carbons long Fatty Acids: Shapes Some are straight, some are bent Bent chains is caused by the presence of double bonds No double bonds → straight fatty acid → saturated fatty acid Saturated with H atoms Each carbon atom is paired with 2 H atoms (besides first and last carbons) Double bonds → bent fatty acid → unsaturated fatty acid Has 2 neighboring carbon atoms that form a double bond Double bond causes a kink in the chain Single double bond: monounsaturated fatty acid 2 or more double bonds: polyunsaturated Saturated: butter, remains solid at room temperature Unsaturated: oil/lipids, liquid at room temperature Naming the Fatty Acid Omega-3 & Omega-6 Liver and muscles store limited glycogen, the liver converts the rest to fatty acids Our cells cannot place the double bond on C 3 or 6, so we get them from our diet Omega-6: Cells convert linoleic acid into omega-6, into arachidonic acid Arachidonic becomes a part of the phospholipids in the cell membranes Omega-3: 3 kinds that we can get from food Differ in # of double bonds and length but all have the first double bond on C3 If your body has enough linoleic acid, it can synthesize DHA and EPA DHA: essential for growth and function of development in brain EPA: lowers blood pressure, reduces clot formation… Trans Fatty Acids Trans configuration: H on opposite sides Cis configuration: H on the same side of the chain All trans fats are man-made (besides the trans fat in butter) Coronary disease PUFA Oils with high amounts of PUFA turn rancid when deep fried Deep frying leads to a free radical (rancid lipid) Phospholipids Carry 2 fatty acids Partially water soluble Differ in length and shape Cell membrane is made of 2 sheets of phospholipids (lipid bilayer) Fatty acid tails are hydro-phobic Cholesterol Found in food Not essential nutrient Liver can synthesize it 5.4 Digestion and Absorption of Lipids Warmth of mouth melts some of the fat Enzymes cleave some of the fatty acids Most chemical digestion of lipids is accomplished in the small intestine with help from the liver, gallbladder and pancreas Hormones indicate the arrival of lipids Epithelial cells of small intestine release hormone into blood stream Gallbladder produces bile into small intestine Bile breaks down large lipid globules into smaller bits called (micelles) Enzyme pancreatic lipase, released into the duodenum for the pancreas, gets to work breaking down the triglycerides into free fatty acids and monoglycerides Absorption of Lipids Short and medium chain fatty acids can cross into the epithelial cells Long chain fatty acids cross into the epithelial cells as micelles They then get repackaged, looks like a golf ball (chylomicron) Chylomicron: type of lipoprotein. Too large to enter the blood vessels, so enters the lacteal vessel. Vessel delivers the golf ball to left subclavian vein Everything inside is nonpolar Allows lipoproteins to dissolve in water 5.4 Lipoproteins Chylomicrons: transport dietary triglycerides VLDLs (very low density lipoproteins): liver converts extra glucose in fatty acids and packages them into VLDLs for delivery to fat cells. Once they deliver their triglyceride, the remnants are cholesterol rich → LDL (low density lipoprotein) LDL delivers cholesterol to the cells HDL (high density lipoproteins): synthesized in the liver. Scavenge for cholesterol from dead and dying cells and return to the liver. Mostly protein 5.5 Lipids, Disease and DRIs Cardiovascular disease (CVD) ~⅓ deaths in Canada are caused by CVD Path to CVD begins with inflammation of arterial wall, due to substances like excess LDL cholesterol, excess glucose, and toxins (cigarette smoke) Irritation increases permeability of arteries and inflammatory response Cells of immune system try to repair Arteries harden and narrow Blood vessels narrow and can become blocked Blocked/narrow arteries can lead to heart attack Reducing the Risk 1. Increase soluble fiber take 2. Limit fat intake to the AMDR 3. Increase omega-3 intake Chapter 6 6.2 Protein Shape and Function Proteins are energy-yielding nutrients and chemically similar to carbohydrates and lipids Amino Acids Building blocks of protein Amino group: 1. Nitrogen atom 2. Acid group 3. Side group 20 different amino acids, each has its own unique side chain Essential Amino Acids 9/20 are essential and must come from the diet 11/20 are synthesized in the liver Non-polar amino acids are lacking oxygen (therefore they do not hydrogen bond) Oxygen-containing polar amino acids are electrically charged and able to form hydrogen bonds Protein Chain of amino acids linked together Covalent bond that links the amino acids are called peptide bonds Protein Shape Polar and charged amino acids are drawn to each other Non-polar amino acids would cluster in the center of the protein Shape is determined by the sequence of amino acids along the chain Changes in environment of a protein may break away the hydrogen bonds, causing protein to unfold (denatured) → no longer functional Denatured Protein Caused by: Change in temperature Change in pH In food, denatured protein changes the texture and consistency of the food Collagen Muscle fibers are held together by collagen Slow cooking meat, collagen denatures Intact collagen increases the resistance to chewing Older the animal, more collagen (hence why veal is more tender) 6.3 Protein Synthesis in the Body We eat protein → digestion breaks them down into amino acids → amino acids are absorbed and delivered to the cells of the body DNA tells the cells the sequence of amino acids to form a protein The gene gets copied onto an mRNA molecule mRNA exits the nucleus and binds to a ribosome Ribosome builds the protein tRNA: transfer RNA Need all 20 amino acids 6.4 Protein Digestion and Absorption Food protein is disassembled in amino acids Amino acids are then absorbed and carried to where they are needed to make proteins needed by the body In the stomach, HCL denatures food protein HCL activates pepsin (enzyme that cuts denatured proteins into smaller polypeptides) Pancreas secretes more pepsin into the small intestine Amino acids are the end products After being absorbed, amino acids enter the hepatic portal vein and travel to the liver then to the rest of the body 6.5 Protein Turnover and Nitrogen Balance Recycling a protein Hemoglobin Protein within the RBCs that carries oxygen to the cells of the body Inside a single RBC there are about 280 million molecules of hemoglobin Nitrogen Balance Protein contains nitrogen, which is essential for the synthesis of many other compounds Without protein turnover, we would need enormous amounts of food to get enough nitrogen Loss of nitrogen occurs in urine, feces and sweat Positive Nitrogen Balance Normally, an adult body maintains nitrogen equilibrium In positive balance during: Pregnancy, lactation, resistance exercise, recovery from illness, children (growing) Negative Nitrogen Balance In negative balance during: Starvation, emotional trauma, other times of trauma Astronauts suffer from muscle wasting during prolonged missions because muscles are not being used, hence why they have to exercise for at least 2 hours a day Deamination The removal of the amino group Without the amino group, all that's left is the carbon skeleton The energy stored in the C-H bonds are used as an energy source Therefore, if you eat too much protein, the liver will deaminate it, and store it as fat. Won’t make it into muscle without resistance exercise 6.6 Protein Disease Food allergies and celiac occur when the immune system responds to protein in food as if it were a harmful pathogen Food Allergies Genetics and food preparation seem to play a major role in the risk of food allergies Celiac Disease Autoimmune disorder Immune system responds to the presence of gluten in the lumen of the small intestine and damages the villi Villi can regenerate once all gluten is eliminated from the diet Non-celiac gluten sensitivity (NCGS) Clinical state of individuals who develop symptoms when they consume gluten containing foods and feel better on GF diet but do not have celiac 6.7 Protein in Food and DRIs EAR of protein is 0.66 g per kg of body weight RDA is about 0.8 g per kg of body weight Intake increases during pregnancy, breast-feeding, infancy and childhood, recovery from illness, blood losses and burns Protein Quality Influenced by: Amino Acid Composition Protein digestibility High quality/complete proteins contain all essential amino acids in adequate amounts and is well absorbed Animal protein Eggs contain all 9 amino acids Low quality/incomplete protein lacks one or more of the essential amino acids and is poorly absorbed Protein Complementation Mixing incomplete plant-based protein sources to provide all essential amino acids without adding animal proteins Grains are a good source of tryptophan and methionine but low in lysine and isoleucine Legumes are low in tryptophan and methionine but high in lysine and isoleucine Chapter 7 7.2 Defining Features of Vitamins Vitamins and minerals are the non-energy yielding micronutrients Chemical Structure Made of carbon, hydrogen, oxygen and sometimes nitrogen and sulfur Source of Vitamins Natural and synthetic sources of vitamins Natural: can come from the 4 kingdoms (plants, animals, fungi, bacteria) Bacteria are single-celled organisms that are put to work in the gut to synthesize vitamins like biotin and vitamin K Synthetic sources: made in a lab. Enrichment Enrichment: process of adding nutrients that were lost during refinement Fortification: adding supplementary nutrients to food to reduce risks of disease at the population level. Milk is fortified with vitamins A and D. Grains are fortified with folic acid Vitamin Solubility Vitamins are classified in terms of suitability Water soluble: vitamins B and C Excreted in urine Insoluble: fat-soluble vitamins like A, D, E, K Stored in fatty tissue (like fat cells and liver) Absorption of Vitamins Bioavailability: how much a vitamin or mineral is absorbed Depends on: Body’s physiological need for it Determined by age, gender, diet How the food was prepared If the nutrient is synthetic, naturally occurring or fortified Function 7.3 Fat Soluble Vitamins Vitamin A and beta-carotene Vitamin A Found in several forms: retinol, retinal, and retinoic acid Retinol: form we absorb from vitamin A-rich animal foods. The liver can convert retinol into the other 2 forms Plants provide the precursor, beta-carotene: carotenoid with orange-yellow pigment Bioavailability of beta-carotene increases if the carrots are cooked. Cooking helps break down the rigid plant cell wall and liberate the beta-carotene Vitamin A functions: cell differentiation, vision, antioxidant Beta-Carotene Lipid soluble Bioavailability increases even more if sauteed Butter turns a deep orange/yellow In the small intestine, the presence of lipids causes the gallbladder to release bile and provitamin gets packaged inside chylomicrons Deep green color of vegetables is the combination of chlorophyll pigment in combination with carotenoids Cell Differentiation Process where newly formed cells form an identity following cell division All body surfaces are covered by layers of epithelial cells Epithelial tissues that line the inside of the body are called mucous membranes Mucus works to lubricate the tissue and protect it from pathogens Diets deficient in Vitamin A affect the proper development of epithelial cells, resulting in little or no mucus production → increase rates of infection from invasive microorganisms → cause damage in the stomach from direct contact with HCl In the small intestine, the site of nutrient absorption, the compromised epithelial cells lead to malabsorption of all nutrients. Deficiency in vitamin A → deficiency in everything else Epithelial cells also cover the skin surface and the cornea of the eye Without vitamin A, keratinization of the skin occurs → skin becomes hard and scaly In the eye, without mucous, the eye cannot clean itself Debris accumulates Leads to xerosis and can create permanent blindness Antioxidant Function Free radicle: molecule with one or more unpaired electron Incomplete valence shell causes the atom to become unstable and highly reactive To retain stability, the free radicle quickly finds a stable compound from which to steal an electron Antioxidants donate electrons to free radicles Vitamin D Sunlight → cholesterol → body heat Vitamin D synthesis is not possible Anything that blocks UV radiation prevents us from synthesizing vitamin D Vitamin D is not common in foods Dairy is fortified with vitamin D AI is 600 IU Functions: build strong bones, enhance/suppress the activity of genes that regulate cell growth Bone Development When skin cells are exposed to UV radiation, radiation converts a substance that is derived from cholesterol into an inactive form of Vitamin D (vitamin D3) D3 is then released into the blood streams Finds its way to the liver Liver converts D3 into another inactive form called calcidiol and releases it again into the bloodstream. Calcidiol eventually finds its way to the kidneys When calcium is needed, the kidneys convert calcidiol into active vitamin D (calcitriol) The active vitamin D travels to the small intestine, enters the epithelial cells that cover the villi and helps absorb calcium Vitamin D increases the bioavailability of calcium When vitamin D is lacking, the intestine only absorbs 10-15% of the calcium in foods. When the vitamin is present, absorption increases up to 80% Once absorbed, calcium gets deposited in the bones Vitamin E Major fat-soluble antioxidant found in cells Defense against free radicles Free radicles damage the polyunsaturated fatty acids in the cell membrane Without vitamin E, red blood cells can break open and spill Free radicals can oxidize LDL that is deposited in plaque Vitamin E protects LDLs and PUFAs from damage Blood Clotting Vitamin K needed, otherwise minor cut can cause massive blood loss Half our vitamin K requirement is met by the actions of the bacteria in the large intestine. Rest is supplied by diet Vitamin K deficiency can occur in some infants. Newborns have a sterile large intestine. Takes weeks to build up bacteria capable of synthesizing vitamin K Vitamin K is not present in breast milk therefore infants are at risk for vitamin K deficiency bleeding To reduce the risk of bleeding to death, newborns are given a single dose of vitamin K at birth 7.4 Water Soluble Vitamins Vitamin B: crucial for energy generation from macronutrients Work as coenzymes, activating enzymes necessary for metabolic reactions Without, energy production is compromised Thiamin (B1): - Essential for energy metabolism - Thiamin deficiency leads to beriberi - Disease linked with diets high in white rice - Most vulnerable were the poor, orphanages and incarcerated - Alcoholism can cause thiamin deficiency, leading to wernicke-Korsakoff syndrome Riboflavin (B2): - Rare - Can cause weakness and sores - Riboflavin degrades in light - Milk in clear container Niacin (B3): - Involved in energy release from macronutrients - Deficiency leads to pellagra, characterized by dementia, dermatitis and diarrhea - Bioavailability of niacin from corn is low unless treated with lime water - Mexican cuisine Vitamin B6: - Serves as a coenzyme for over 100 enzymes - Is vital for amino acid metabolism and heme synthesis - Deficiency can lead to armenia → Cardiovascular disease risk Folate: - Critical for DNA metabolism - Deficiency during early pregnancy can cause neural tube defects like spina bifida - Plays a role in red blood cell production Vitamin B12: - Necessary for energy metabolism and nerve health - Requires intrinsic factor produced in the stomach - Lack of intrinsic factor leads to pernicious anemia Pantothenic Acid and Biotin: - Deficiencies are rare due to their wide availability in foods and low requirements Vitamin C: - Bone formation - Essential for collagen synthesis - Deficiency leads to scurvy - Weakened connective tissue and open wounds - Antioxidant function - Water-soluble antioxidant, protecting cells from oxidative damage - Increased intake is recommended for smokers to aid lung tissue repair Chapter 8 8.2 Defining Features of Minerals Humans require 7 major minerals and 8 trace minerals 3-25% of elements found on earth are required by the human body Trace minerals are less abundant, therefore require less of them Iron: most abundant trace mineral Fluid inside a cell: intracellular fluid Minerals populate the intracellular fluid compartment Body cells are surrounded by extracellular fluid (interstitial or intercellular fluid) Fluid in blood vessels: intravascular Because of the leakiness of blood capillaries, minerals that reside in extracellular fluids can move freely from the intravascular to interstitial fluids Water Hard water contains calcium, magnesium and others Can taste and smell unpleasant Soft water contains sodium or potassium Makes more bubbles with less soap Soft water can be high in sodium, and exacerbate hypertension while hard water may reduce hypertension. 8.3 Major Minerals Calcium - Bone health: - Most abundant mineral in the body - Forms hydroxyapatite crystals on a collagen foundation, crucial for bone structure - Acts as a reservoir to maintain blood calcium levels - Neural Communication: - Floods into the neurons to facilitate neurotransmitter release, allowing electrical signals to pass between neurons - Low blood calcium can lead to convulsions - Calcium Homeostasis: - Body regulates calcium levels through osteoblasts (bone-building cells) and osteoclasts (bone-reabsorbing cells) - Parathyroid hormone (PTH) and vitamin D play critical roles in maintaining blood calcium levels by increasing absorption from the intestines and reducing urinary excretion - Bioavailability: - Not all dietary calcium is absorbed effectively - Spinach, high in calcium, low in bioavailability because of oxalates  - Dairy products provide high calcium content and bioavailability - Peak Bone Mass: - Achieving peak bone mass in early adulthood is vital for long-term bone health - After age 30, bone density typically declines - Especially in women post-menopause due to decreased estrogen levels - Osteoporosis: - Condition that results in porous and fragile bones - Increases fracture risk - Preventative measures: - Maximizing peak bone mass - Engaging in resistance exercise - Meeting calcium RDA Other Minerals - Phosphorus: - 85% of phosphorus combines with calcium in the bones - Deficiency is rare - Excessive phosphorus intake from processed foods can lead to dental issues - Magnesium: - Over 50% of the body’s magnesium is found in bones and is important for forming hydroxyapatite crystals - Many people do not meet the recommended intake due to low consumption of magnesium-rich foods - Sodium: - Crucial for fluid balance and nerve impulse transmission - Excessive intake can lead to hypertension - Most sodium comes from processed foods rather than added salt - Potassium: - Mainly found inside cells - Helps lower blood pressure and counteract sodium effects - Fruits are a good source 8.4 Trace Minerals Have only been recognized as essential to humans in the last 60 years Most abundant: iron Iron - Over 60% found inside RBC - Every day we produce 2 billion new RBCs - Each RBC has 280 million hemoglobin molecules - Each hemoglobin is studded with 4 heme compounds that bind to iron - Iron binds to the oxygen that we inhale - As we inhale, lungs fill with oxygen  - Oxygen crosses through the epithelial cells of the lungs and enters the blood capillaries - Oxygen enters the RBCs and binds to the iron - Epithelial cells of the small intestine produce ferritin (iron-binding protein) - Ferritin binds and stores iron - When iron intake levels are low, low amounts of ferritin are synthesized - During state of iron abundance: larger amount of ferritin are made that bind to iron inside the epithelial cells - Preventing it from entering blood capillaries Bioavailability of Iron - Depends on body’s physiological need - Animal flesh: rich supplied with blood - Blood contains RBCs with hemoglobin - Source of heme-iron - Plants: non-heme iron Anemia - Low iron → low hemoglobin concentration → oxygen transport in blood is impaired → person has to work harder to circulate oxygen-poor blood → leads to hypertension → overworked heart → heart enlarges → heart failure - High risk groups: women (during period stages, pregnancy stages), infants, young children, teenagers (because of rapid growth) Iodide - Iodide ends up in the thyroid - Thyroid hormones regulate body temperature and body metabolism - Iodide source: ocean - Goiter: condition caused by deficiency in iodide - Results in enlarged thyroid gland - Gland enlarges in hopes of capturing more iodide from the blood, but there is no iodide - Cretinism: - Most damaging consequence of lack of iodide - Affects developing fetus - Physical and mental development is stunted Chromium - Enhances the ability of insulin to take glucose into the cells - Helps with glucose metabolism - Supposed to build muscle and burn fat - Not proven Zinc - Deficiency: impairs growth and development - Increases risk of infection - Immune function - Zinc lozenges can reduce cold symptoms Selenium Can protect against some forms of cancer Depends on geographic location (like with iodine) Soil in Brazil is richest in selenium - Brazil nuts Fluoride Gets deposited in hydroxyapatite crystals in teeth to form fluorapatite Makes teeth more resistant to decay Chapter 9 9.2 Osmosis Adult body contains about 40L of water ⅔ inside cells ⅓ in the extracellular fluid compartment Diffusion of water through a selectively permeable membrane Body maintains fluid balance by controlling solute concentrations in different compartments Where ions go, water follows Water molecules move toward areas with higher solute concentration Ex: - Salting an eggplant draws water out of the cells to the surface where salt is concentrated - Raisins swell in water as water moves into them due to their higher sugar concentration - Salting meat too early can prevent proper searing by drawing out water 9.3 Functions of Water in the Body Blood plasma, which is mostly water carries nutrients to cells and waste to the kidneys for elimination Urine is primarily water with suspended body waste Water regulates body temperature Blood carries heat from metabolic reactions to the skins surface, where capillaries dilate to allow more blood flow Increased blood flow at the skin’s surface enables heat dissipation Causes redness of skin during exercise Sweat Essential for body cooling Effectiveness depends on evaporation 9.4 Roles of Kidneys Human body is 50-70% water Varies per age and sex Newborns: about 75% water Elderly’s: 45% water Men typically have more body water due to higher lean tissue mass Daily water intake comes from: beverages, food, metabolic water production Water losses: urine, sweat, expired air, feces Kidneys and brain work together to main proper body fluid levels Function of kidney: - Waste elimination - Kidneys process about 5 cups of blood per minute - Produce approx 1 ml of urine per minute - Blood enters via renal artery, exits via renal vein - Blood pressure control - Kidneys regulate blood volume, pressure and solute concentration - Blood plasma is about 92% water, affecting blood pressure - Hormone interaction - Antidiuretic hormone (ADH) from the pituitary gland and aldosterone from adrenal glands control urine volume and concentration - ADH conserves water when blood volume is low or sodium concentration is high - Aldosterone reduces sodium elimination in urine, conserving water Managing Blood Pressure - DASH diet (Dietary Approaches to Stop Hypertension) recommends: - Increasing potassium and magnesium intake - Reducing sodium intake - This approach can lower blood pressure by drawing water into cells from extracellular fluid compartments 9.5 Water Toxicity Water deficiency: - Cause: vomiting and diarrhea can lead to excessive water loss - Prolonged physical activity can result in loss of water and electrolytes through sweat Hyponatremia: - Low sodium levels in the blood - Symptoms: severe headaches, confusion, seizures - Occurs when water moves from extracellular compartments into cells - Requires immediate medical attention Treatment and Prevention: - Mild dehydration can be treated with water intake - Severe dehydration requires replenishment of water and electrolytes Water Toxicity: - No UL but overconsumption can be dangerous - Causes:  - Overconsuming plain water after physical activity - Extreme thirst (can be caused by ecstasy) - Symptoms: - Headaches - Confusion - Seizures - Coma - In extreme cases, death - Mechanism: - Excess water dilutes blood sodium concentration - Leads to hyponatremia - Causes water to move into cells 9.6 Metabolism Sum of all chemical reactions in the body Can be anabolic or catabolic Rate of reactions determines if metabolism is “high” or “low” Anabolic Reactions: - Build larger, more complex compounds from simpler ones - Require energy input - Building glycogen from glucose - Forming triglycerides and proteins from their building blocks Catabolic pathways: - Break down compounds into smaller pieces - Release energy - Breakdown of glucose, glycerol, fatty acids and amino acids - Energy released is: - Partially lost as heat - Partially transferred to ATP ATP (Adenosine Triphosphate): - Energy currency of the cell - Required for organs like the liver to run anabolic reactions 9.7 ATP Primary energy currency of cells Structure and Composition ATP is a nucleotide consisting of 3 main components: 1. Adenine (nitrogenous base) 2. Ribose (sugar) 3. Three phosphate groups ATP Synthesis Primarily produced in the mitochondria through oxidative phosphorylation: - Nutrients provide high-energy electrons (in the form of NADH) - Electron transport chain pumps protons from the matrix to the intermembrane space - Proton gradient drives ATP synthesis via ATP synthase Process generates approximately 32 ATP molecules per glucose molecule oxidized Functions of ATP 1. Energy transfer: ATP powers various cellular processes by transferring phosphate groups (phosphorylation) 2. Muscle contraction: provides energy for muscle fiber sliding and contraction 3. Enzyme activation: phosphorylates enzymes, changing their configuration to perform work 4. Transport processes: powers ion pumps like the sodium-potassium pump 5. Biosynthesis: supplies energy for the synthesis of macromolecules ATP Utilization and Regeneration - Cells constantly break down and regenerate ATP - ATP hydrolysis releases energy and converts ATP to ADP - ADP is then reconverted to ATP through cellular respiration - Human body uses and regenerates approx 100-150 moles of ATP daily Mitochondrial Distribution - Number of mitochondria in cells varies based on metabolic demands - High in energy-demanding cells - Muscle cells, liver cells - Lower in less metabolically active cells - Fat cells Efficiency and Heat Production ATP synthesis is not 100% efficient: - About 40% of the chemical energy from glucose is stored in ATP - Remaining 60% is lost as heat Process contributes to maintaining body temperature 9.8 Energy Input and Output Energy balance is crucial for maintaining stable body weight Basal Metabolism (BMR) Energy expended at rest for vital functions (breathing, circulation, organ maintenance) Measured after fasting for 12 hours Thermic Effect of Food (TEF) Energy required for digestion, absorption and metabolism of food Consumes about 10% of total caloric intake Factors Influencing BMR Body composition: more muscle increases BMR Sex: men have higher BMRs than women Age: BMR decreases with age, children have higher BMRs Body Surface Area: Taller people have higher BMR due to greater heat loss 9.9 Genetic and Environmental Factors of BMR Environmental Factors: - Prenatal environment - Low birth weight babies have a higher risk of adult obesity - Thrifty Gene Theory suggests fetuses deprived of calories may lower their BMR in anticipation of food scarcity - Diet Quality - Maternal nutrition can affect offspring risk of obesity Epigenetics: shows how environmental factors can alter gene expression Nutritional Genomics: - Nutrigenomics: - Examines how food influences gene expression - Nutrigenetics: - Investigates how genetic differences affect nutrient metabolism