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Stack #212033

What are elements? Substances that cannot be broken down into simpler substances by ordinary chemical means
What are the 4 main elements responsible for 96% mass of an organism? oxygen, carbon, hydrogen, nitrogen
what are 2 trace elements? Copper, iodine
What is the smallest portion of an element? Atom
Functions of elements:oxygen cellular respiration
carbon backbone of organic molecule
hydrogen energy transfers, passed around in e- transfers
nitrogen component of protein & nuclei acids, exists in chlorophyll(plants)
calcium bones & teeth, aids in muscle contraction, boosts immune system, conducts nerve impulses, aids in blood clotting, plant cell wall
sodium fluid balance, conduction of nerve impulses, photosynthesis
magnesium needed in animals blood,activates many enzymes, chlorophyll
chlorine water balance (-charged), photosynthesis
iron component of hemoglobin, activates few enzymes
atomic # number of protons
atomic mass sum of protons & neutrons
isotopes same element, different neutrons
what is a chemical bond? atoms of a compound held together by forces of attraction
what is bond energy? energy necessary to break chemical bond
what is covalent bond sharing electrons
covalent compound compound of mainly covalent bonds
ionic bond attraction between positive charge of cation and negative charge of anion
ionic compound anions and cations bonded together by their opposite charges
ion atom that has lost or gained electrons
cation positive ion
anion negative ion
polyatomic ion group of covalently bonded atoms
water % 70% of humans total body weight, 85% brain cells, 20% bones
cohesion water molecules stick to each other
adhesion ability to stick to many kinds of substances
potential energy resting energy
kinetic energy energy in motion - speeding molecules up
heat total kinetic energy
temperature average kinetic energy
ionize potential of water to dissociate into hydrogen ions(H+) and hydroxide ions(OH-)
acid yields hydrogen ions(H+)& anion
base yields hydroxide ions(OH-) & cation
pH degree of solution's acidity (neutral 7, acid <7, base >7)
buffer resists changes in pH when acid/base added
salt formation a strong acid & a strong base will yield a salt in water
electolytes ions that conduct electrical current
nonelectrolytes sugars, alcohols, other substances that do not form electrolytes
carbohydrates immediate energy source - sugars, starches, cellulose (monosaccharides, hexoses, glucose, disaccharide, polysaccharide, starch)
lipids fats - long-term energy storage - soluable in nonpolar solvents, insoluble in water (triaglycerol, glycerol, fatty acid, saturated fatty acid, unsaturated fatty acid,phospholipids, carotenoids, steroid, protaglandins, van der waaals interactions)
Van der Waals interactions weak attractions that occur
prostaglandins promote inflammation and smooth muscle contraction
proteins macromolecules(large/complex)of amino acids joined by peptide bonds (enzymes, amino acids)
nucleic acids transmit heredity information and determine what protein a cell manufactures (DNA/RNA)
3 major pyrimidine bases cytosine, thymine(DNA), uracil(RNA)
2 major purine bases adenine, guanine
what are cells the basic living unit of organization, smallest unit of life
prokaryote no nucleus(bacteria)
eukaryote at least 1 nucleus 1 part of life
3 different components of eukaryotic cell plasma membrane, cytoplasm w/organelles, nucleus w/nucleolus
plasma membrane outside layer of cell, regulates what goes in and comes out of cell, selectively permeable
cytoplasm plasma membrane and cell contents outside of nucleus
organelles within cytoplasm
Ribosomes most numerous of organelles, site of protein synthesis
Created by: banksm341