Question | Answer |
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 |