Chemical Level Wednesday September 05 2012 12 09 PM Composition of Matter Matter Anything that occupies space and has a mass Atoms are the building blocks of matter charge neutral Inert Elements Atoms with complete valence shells chemically inert unreactive Chemically Reactive Elements Atoms with incomplete valence shells unstable reactive Chemical Level Biochemical reactions occur in the cells to define physiology study of function Explained by reactivity of atoms to achieve stability Atoms strive to complete outermost shell valence shell Octet Rule strive to complete 2nd 3rd shell with 8 electrons not 1st shell b c it can only accommodate 2 electrons Atoms has 3 subatomic particles Protons charge Neutrons no charge Electrons charge Atomic nucleus positively charged Atomic number of protons in nucleus of electrons Electrons located in orbitals shells around the nucleus Overall charge of an atom 0 Covalent Bonds electrons shared to attain stability Polar covalent Non polar covalent Ionic Bonds Complete transfer of electrons Atom donating becomes CATION positive charge Atom accepting becomes ANION negative charge Hydrogen Bonds Weak bond between hydrogen atoms With the exception of the noble inert gases which come with complete valence shells atoms achieve stability by completing their outermost shell through chemical reactions through which atoms may gain lose or share electrons to achieve stability Atom GAINS Electron ANION charge Atom LOSES Electron CATION charge Anions Cations form Ionic Bonds When atoms share electrons to achieve stability the bond formed is a covalent bond Non Polar Equal sharing of electrons Polar Covalent Unequal sharing of electrons The atom that pulls the shared electrons is referred to as an Electronegative Atom other atom referred to as an Electropositive Atom POLAR COVALENT BOND is always ELECTROPOSITIVE with hydrogen binds will always form other electronegative atoms Hydrogen bonds are molecular bonds that form to hold larger molecules together Macromolecules Based on the biochemical reactions occurring in the cells Inorganic Compounds do not contain carbon chains except CO2 CO Organic Compounds Contain carbons that are covalently bonded 2 Categories 70 cells Water Universal Solvent High Heat capacity absorbs body heat High heat of vaporization cools body down water evaporates sweat Cushions major organs brain Acids Substances that release Hydrogen Ions H Proton Donors Blood pH is maintained b t 7 35 7 45 actions of enzymes in physiological processes Acidosis increase in H in blood Bases Substances that accept H Proton Acceptors Acid base balance is regulated by buffers chemicals that resist abrupt changes in pH Inorganic compounds in the human body 1 Water Universal Solvent 2 Acids proton donors release H a proton H determines pH of a solution pH 1 H High H Low pH Inverse relationship Blood 7 35 7 45 optimum body function due to presence of enzymes To maintain homeostasis of blood pH buffers are used in the body Acidosis Decrease in blood pH 7 15 Buffer system will BIND H to raise the blood pH to normal Alkalosis Increase in blood pH 7 56 Buffer system will RELEASE H to drop the blood pH to normal Salts Ionic compounds that dissociate completely in water to give Cations Anions Organic Compounds Carbohydrates Monosaccharaides general formula sweet soluble in water Hexose glucose fructose galactose Pentose deoxyribose ribose Disaccharides composed of 2 hexose sugars sweet soluble in water Maltose grain sugar Sucrose table sugar Lactose milk sugar Starch plant cells Glycogen animal cells Lipids Hydrophobic substances liquid Polysaccharides composed of long chains of glucose storage Neutral Fats Triglycerides most abundant form of fat in human body Fats solid Oils Saturated single covalent bonds solid ex butter Low density lipoprotein LDL BAD CHOLESTEROL High density lipoprotein HDL GOOD CHOLESTEROL Unsaturated at least one double covalent bond liquid ex olive oil Phospholipids glycerol backbone 2 free fatty acid chains phosphorus containing group Steroids derived from cholesterol Eicosanoids Proteins Nucleic Acids 4 Types of Organic compounds in the human body Carbohydrates CH2O Monosaccharaides Disaccharides Maltose Glucose Glucose Grain sugar Sucrose Glucose Fructose Table Sugar Lactose Glucose Galactose Milk Sugar Polysaccharides Lipids hydrophobic insoluble in water Neutral Fats Abundant in the human diet Unsaturated Liquid Saturated Solid Transported in the aqueous environment In the human body covered by proteins to form Lipoproteins Lipid Protein Proteins are more dense than liquids Phospholipids Steroids Eicosanoids Very Low Density Lipoprotein vLDL Triglyceride major neutral fats Most common in human diet vLDL transports triglycerides to cells for energy production for storage and for cushioning of organs in the body Fat triglycerides is the most common and efficient form of stored energy 1g fat yields 9 Kcal 1g glucose yields 4 Kcal 1g protein yield 4 Kcal Low Density Lipoprotein LDL Bad Cholesterol Lipids Proteins Transport s cholesterol to the plasma membrane cholesterol maintains integrity of the plasma membrane Transports cholesterol to steroidogenic cells for the synthesis of the steroid hormones testosterone estrogen cortisone etc Too much cholesterol in the form of LDL is bad for you Cholesterol in LDL s settles in the internal walls of the blood vessels to form plaque Therosclerotic Plaques In large blood vessels partially block the blood vessels and impede blood flow Result Hypertension High blood pressure Heart beat increases to compensate for the increase in resistance to blood flow Result Enlarged Heart Cardiomegaly Cardiomegaly can result in heart failure If an atherosclerotic plaque dislodges from the internal wall of a blood vessel it floats in the bloodstream Free floating plaques Emboli If Emboli lodges in smaller blood vessels they occlude the blood vessels prevent blood flow through the occluded blood vessels hence tissues served by the occluded blood vessels die due to lack of oxygen nutrients Cerebral vessels in brain and the coronary vessels of heart are the smallest blood vessels that are often occluded leading to Ischemic Strokes Brain Attack and myocardial infection Heart Attack High levels of LDL can result in Bad High Density Lipoprotein HDL Good Cholesterol Proteins Lipids HDL s transport cholesterol in the blood stream to the liver for degradation and elimination from the body Good Atherosclerotic Plaque plaque
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