THE CHEMICAL LEVEL Level 1 Composition of Matter Matter anything that occupies space and has mass composed of elements composed of identical atoms Atoms are the building blocks of matter there are 112 elements most body weight is made up of 4 major elements 96 of the body weight is made up of Oxygen Carbon Nitrogen and Hydrogen Structure of an Atom Atomic Orbits Shells each atom is composed of 3 subatomic particles Protons charged subatomic particles in the center of the atom nucleus of protons atomic Neutrons uncharged subatomic particles inside the nucleus Net charge of nucleus is thus positive Electrons charged subatomic particles in the orbits shells surrounding the nucleus In an atom of protons of electrons Thus the overall charge of an ATOM is ZERO atom is electrically neutral electrons are located arranged in the orbits shells in a specific manner 1st shell closer to nucleus can accommodate a max of 2 electrons 2nd shell can accommodate a max of 8 3rd shell can accommodate a max of 18 electrons but atom is stable with 8 the octet rule the outermost shell in an atom is the VALENCE shell and the electrons in it are the valence electrons without the max of electrons the atoms is unstable and therefore chemically reactive Chemically Inert and Chemically Reactive Elements Inert atoms with valence shells complete i e noble gases Reactive atoms with incomplete valence shells achieve stability by forming chemical bonds with other atoms using their valence electrons covalent bonds or by transferring e s ionic bonds basis for chemical reactions inside the human body result in formation of molecules and compounds Molecule involves the same atoms Compound involves different atoms 3 Types of Chemical Bonds Covalent e s are shared between atoms to attain stability Nonpolar e s are shared EQUALLY between atoms i e CO2 Polar UNEQUAL sharing of e s ELECTRONEGATIVE Atom one atom pulls the shared e s closer to itself ELECTROPOSITIVE Atom i e H2O Oxygen electronegative Hydrogen electropositive Ionic involve complete transfer of e from one atom to the other resulting a charged particle called IONS CATION atom donating the e s ANION atom accepting the e s Ionic Bond opposites attract Hydrogen weaker bond that forms between hydrogen atoms and electronegative ions H bonds form between atoms already involved in Polar Covalent Bonds Important Compounds in the Human Body 2 Categories Inorganic Compounds no carbon chains except CO2 and CO Water Acids Bases and Salts Organic Compounds contain carbons that are covalently bonded Carbohydrates Lipids Proteins and Nucleic Acids Water Polar Covalent Molecule most abundant compound in the body 70 of volume of cells 40 L 27L inside cells ICF and 13L of ECF ECF made of interstitial fluid thin film of fluid surrounding cells in tissues and blood plasma inside blood vessels interstitial fluid allows for transfer of substances across the plasma membrane of cells anything diffusing from blood inside capillaries has to cross capillary membrane into interstitial fluid then across the plasma membrane into cytoplasm known as the universal solvent high heat capacity absorbs body heat high heat of vaporization water evaporated from the body using large amounts of heat cools the body for cushioning around the body organs such as the brain H atoms don t cause stability but H bonds cause stability of polar covalent bonds and cause molecules to form macromolecules H bonds formed between electropositive H atoms and other electronegative atoms based on these types of chemical reactions you form 2 types of compounds in the body Organic and Inorganic Acids and Bases Acids substances that release H ions H protons Proton Donors negative log of the H pH H is inversely proportional to the pH blood pH is maintained between 7 35 7 45 optimum pH for the actions of enzymes involved in physiological processes Bases substances that accept H Proton Acceptors Acid Base balance is regulated by Buffers chemicals that resist abrupt changes in pH by binding H when the pH falls and by releasing H when the pH rises salts are ionic compounds that dissociate completely in water to give cations and anions Dissociation of a Salt in Water Organic Compounds Carbohydrates Monosaccharides general formula CH2O n sweet and soluble in water 2 types Hexose CH2O 6 glucose fructose galactose Pentose CH2O 5 deoxyribose ribose Disaccharides composed of 2 hexose sugars sweet and soluble in water 3 types Maltose grain sugar glucose glucose Sucrose table sugar glucose fructose Lactose milk sugar glucose galactose Polysaccharides composed of long chains of glucose storage form of glucose known as starch in plant cells and as glycogen in animal cells not sweet and insoluble in water Lipids hydrophobic substances insoluble in water 4 types Neutral Fats composed of a glycerol backbone and 3 free fatty acid chains attached looks like the letter E most abundant form of fat in the human diet known as FATS when solid and OILS when liquid 2 types Unsaturated at least one double covalent bond in the carbon chain liquid at room temp plant sources olive oil Saturated single covalent bonds exist between all the carbons in the chain solid at room temp animal sources butter increase LDL increase myocardial infarction and strokes 3 types of Lipoproteins named based on lipid to protein ratio vLDL very low density lipoproteins lipid protein major lipid is neutral fats triglyceride can cause weight gain transport triglycerides in bloodstream to adipose tissues where the triglycerides are stored as the most concentrated form of stored energy and provide cushioning for vital organs in the body cavities LDL low density lipoprotein lipid protein major lipid is cholesterol high levels of vLDL can be converted into LDL if high levels of cholesterol are present in the blood transports cholesterol to the plasma membrane cholesterol maintains integrity and LDL transports cholesterol to the steroidogenic cells cells that synthesise steroid hormones excess LDL stays in the blood stream and they attach and release the cholesterol to the internal surface of the blood vessels first deposit occurs with surface of blood vessel is streaked destroyed builds overtime and will occlude blood flow increase in BP OR plaque can break off and float freely in blood embolus and can block arteries and smaller blood vessels coronary heart or cerebral brain MI or stroke coronary vessels plaque can form in the vessels or it can show up via embolus infarction
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