Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Radical (chemistry) wikipedia , lookup
Nucleic acid analogue wikipedia , lookup
Photosynthetic reaction centre wikipedia , lookup
Drug discovery wikipedia , lookup
List of types of proteins wikipedia , lookup
Metalloprotein wikipedia , lookup
Evolution of metal ions in biological systems wikipedia , lookup
Unit 1 The Nature of Life Ch. 2 The Chemistry of Life Atoms Atom - the basic unit of matter The subatomic particles that make up atoms are protons, neutrons, & electrons Atoms Nucleus - the center of the atom Electron - a negatively charged particle Elements & Isotopes Element - a pure substance that consists entirely of one type of atom Isotopes - atoms of the same element that differ in number of neutrons Because they have the same # of electrons, all isotopes of an element have the same chemical properties Isotopes of Carbon Chemical Compounds Compound - a substance formed by the chemical combination of 2 or more elements Ex.) NaCl Chemical Bonds The 2 main types of chemical bonds are ionic bonds & covalent bonds Ionic bond - formed when 1 or more electrons are transferred from 1 atom to another Ions - positively & negatively charged atoms Sodium Chloride - An Ionic Bond Chemical Bonds Covalent bond - forms when electrons are shared between atoms Molecule - the smallest unit of most compounds Chemical Bonds Van der Waals Forces - the slight attraction between oppositely charged, nearby molecules The Water Molecule A water molecule is polar because there is an uneven distribution of electrons between the oxygen & hydrogen atoms The Water Molecule Cohesion - an attraction between molecules of the same substance Ex.) Water The Water Molecule Adhesion - an attraction between molecules of different substances Ex.) Water molecules to glass Solutions & Suspensions Mixture - a material composed of 2 or more elements or compounds that are physically mixed together, but not chemically combined Solutions & Suspensions Solution - all components evenly distributed Solute - the substance that is dissolved Solvent - the substance in which the solute dissolves Ex.) In a saltwater solution, salt is the solute & water is the solvent Acids, Bases, and pH pH scale - measurement system to indicate the concentration of H+ ions in solution, ranges from 0-14 Acids, Bases, and pH Acid - any compound that forms H+ ions in solution Acidic solutions have higher concentration of H+ ions than pure water & have pH values below 7 The greater the concentration of H+ ions, the lower the pH number Acids, Bases, and pH Base - a compound that produces hydroxide ions in solution Basic, or alkaline, solutions have lower concentrations of H+ ions than pure water & have pH values above 7 The lower the concentration of H+ ions, the higher the pH value (up to 14) Acids, Bases, and pH Buffers - weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH The Chemistry of Carbon Organic compounds - compounds created by organisms 4 groups of organic compounds found in living things are carbohydrates, lipids, nucleic acids, & proteins Carbohydrates Carbohydrates - compounds made up of carbon, hydrogen, & oxygen atoms Living things use carbohydrates as their main source of energy Ex.) Starches & sugars Lipids Lipids - made mostly from carbon & hydrogen atoms They can be used to store energy Ex.) fats, oils, waxes Nucleic Acids Nucleic acids - molecules that store & transmit genetic information, made up of nucleotides Nucleotide - has 3 parts: a 5-carbon sugar, a phosphate group, & a nitrogenous base Nucleic Acids There are 2 kinds of nucleic acids: RNA (ribonucleic acid) & DNA (deoxyribonucleic acid) RNA contains the sugar ribose, DNA contains the sugar deoxyribose Proteins Proteins - molecules that contain nitrogen, carbon, hydrogen, & oxygen Proteins are made up of chains of amino acids Proteins Amino acids - compounds with an amino group on one end & a carboxyl group on the other end, there are more than 20 in nature Proteins - Proteins help to carry out chemical reactions, transport small molecules in & out of cells, & fight diseases Chemical Reactions Chemical reaction - process that changes, or transforms, 1 set of chemicals into another Reactants - the elements or compounds that enter into a chemical reaction Products - elements or compounds produced by a chemical reaction Chemical reactions always involve changes in the chemical bonds that join atoms in compounds Energy in Reactions Energy is released when chemical bonds are broken, & absorbed when chemical bonds are formed Energy Changes Chemical reactions that release energy often occur spontaneously Reactions that absorb energy will not occur without a source of energy Energy Changes Organisms need to carry out reactions that require energy in order to stay alive Humans release the energy needed to grow, breathe, think, & even dream through chemical reactions Chemical reactions occur when humans metabolize, or break down (digest) food Activation Energy Activation energy the energy needed to get a reaction started Enzymes Catalyst - a substance that speeds up the rate of a chemical reaction Enzymes - proteins that act as biological catalysts Enzymes speed up chemical reactions that take place in cells Enzymes Enzymes are specific, they catalyze only 1 chemical reaction Enzymes provide a site where reactants can be brought together to react Substrates - the reactants of enzymecatalyzed reactions The Enzyme-Substrate Complex The enzyme-substrate complex is a site where reactants can be brought together to react Regulation of Enzyme Activity Enzymes may be affected by a change in pH, temperature, or a change in shape pH & temperature cause enzymes to change their shape, preventing them from fitting together in the enzymesubstrate complex