Unit 2: The Chemistry of Life PDF

Chapter 2 Chemistry of Life Sections 2.1-2.3 Atoms Atoms/Elements The study of chemistry begins with the basic unit of matter, the atom Protons (+ charge) Neutrons (no charge) Electrons (- charge) Atoms Important to Life We have organized the 110+ different atoms/el...

Chapter 2 Chemistry of Life Sections 2.1-2.3 Atoms Atoms/Elements The study of chemistry begins with the basic unit of matter, the atom Protons (+ charge) Neutrons (no charge) Electrons (- charge) Atoms Important to Life We have organized the 110+ different atoms/elements into the Periodic Table of Elements The major elements found in all living things are: C, H, N, O - make up 95% of all atoms in living things Chemistry of Life Biochemistry ▫ Chemistry of living organisms Atoms/Elements come together to form molecules Lots of water molecules ▫ Smallest unit of that substance that still has the properties of that substance e.g., H2O molecules Atoms Form Bonds Atoms come together to gain/lose/share electrons to fill their outer most electron shell ▫ Chemical bonds Atoms joining to form a molecule 2 basic types of chemical bond ▫ Ionic Bonds ▫ Covalent Bonds Atoms Form Bonds Ions ▫ Positive (+) Ions Atoms with a +charge because they have lost electrons e.g., Sodium (Na) gives up an electron and become Na+ ▫ Negative (-) Ions Atoms with a - charge because they have gained electrons Atoms Form Bonds Ionic Bond ▫ When atoms transfer electrons to other atoms and then attract each other e.g., Na+ attracts Cl- 🡪 NaCl (table salt) Atoms Form Bonds Covalent Bond ▫ When 2 or more atoms share electrons to fill outermost electron shell Types of Covalent Bonds Covalent bonds do not always share electrons evenly Unequal sharing 🡪 Polar Covalent Bonds ▫ e.g., water (H2O), sugar ▫ One side of the molecule has a slight positive (+) charge, the other side has a slight negative (-) charge Types of Covalent Bonds Water has a polar covalent bond ▫ O side is - and the H side is + Types of Covalent Bonds Equal sharing🡪 Nonpolar Covalent Bond ▫ e.g., H2, oil, fat, wax Vegetable Oil Types of Covalent Bonds Polar molecules (ex. sugar) and ionic compounds (ex. NaCl) easily dissolve in water Nonpolar molecules (ex. fats and oils) will not dissolve in water Hydrogen Bonds Hydrogen Bonds ▫ Polar molecules form weak bonds between a slightly positive hydrogen (H) atom in the molecule and a slightly negative atom in another polar molecule e.g., Hydrogen bonds keep water molecules together pH in Living Organisms Water can undergo Ionization ▫ The process by which a nonionic compound is converted to ions ▫ In some natural reactions H2O becomes: H+ (Hydrogen ions) OH- (Hydroxide ions) pH in Living Organisms Cells need ideal levels of H+ & OH- to function normally (they need a stable pH) The concentration of H+ ions and OH- ions in a solution, is measured using the pH scale ▫ The pH scale ranges from 0 to 14  The pH Scale Copyright Pearson Prentice Hall Acids, Bases, and pH At a pH of 7, the concentration of H+ ions Sea water and OH- ions is equal. Human blood Pure water Milk Normal rainfall We call this Neutral Pure water has a pH of 7.  The pH Scale Copyright Pearson Prentice Hall Acids, Bases, and pH Solutions with a pH less than 7 have more H+ ions than OH- ions. We call this Acidic Acid rain Tomato juice The lower the pH, the Lemon juice greater the acidity. Stomach acids  The pH Scale Copyright Pearson Prentice Hall Oven cleaner Bleach Acids, Bases, and pH Ammonia solution Soap Solutions with a pH greater than 7 have more OH- ions than H+ ions. We call this Basic The higher the pH, the more basic the solution. Ideal pH and Buffers The pH of the fluids within most cells in the human body must generally be kept between 6.5 and 7.5. If the pH is lower or higher, it will affect the chemical reactions that take place within the cells. Ideal pH and Buffers To make sure the pH stays stable, living things contain Buffers (weak acids and bases) Buffers help prevent sudden changes in pH ▫ Work until an acid or base overwhelms the buffer. Then pH will start to change Buffers in living organisms help those organisms maintain homeostasis = stable internal environment ▫ e.g., Buffers in blood to keep it neutral Carbon Found in all living organisms Bonds to H, O, N, P & S Can form a long chain or rings of carbons ▫ Organic molecules Carbon Organic molecules: ▫ Have a carbon backbone ▫ Are found in living organisms ▫ Come in 4 groups (Carbon macromolecules): Carbohydrates Lipids Nucleic acids Proteins Carbon Macromolecules Carbon macromolecules are really large molecules made from simple organic molecules ▫ Small/Simple molecules are called monomers ▫ Monomers join together to form larger molecules called polymers in a process called polymerization Really large organic polymers are called macromolecules Carbohydrates Made of C, H, O in a 1:2:1 ratio (CH2O) Provide “quick” energy Building blocks of carbohydrates are simple carbs called monosaccharides Monosaccharides are simple sugars like glucose (C6H12O6) & fructose Carbohydrates 2 monosaccharides can combine to make disaccharide e.g., glucose + fructose = sucrose (table sugar) Several monosaccharides can combine to make a polysaccharide or a complex carbohydrate e.g., Glycogen, starch & cellulose Lipids Made of C, H, O but in no specific ratio Several functions include: Long term energy storage Make up cell membranes Waterproofing ▫ Nonpolar 🡪 do not dissolve in water The building blocks of lipids are glycerol and fatty acids (ex, Fats, Waxes, and Oils) Lipids Saturated Fats ○ Fat molecules that have single bonds between all of their carbon atoms Solid at room temperature ex. butter, lard (animal fat) Unsaturated fat ○ Fat molecules that have at least one double bond between carbon atoms Liquid at room temperature ex. vegetable oil Nucleic Acids Made of C, H, O, N, P Store & transmit genetic information ▫ 2 types = DNA & RNA Building blocks of nucleic acids are called nucleotides which are made of: ▫ 5 carbon sugar (ribose or deoxyribose) ▫ Phosphate group ▫ Nitrogen-containing base Nucleic Acids Nucleotide Proteins Made of C, H, O, N (some have sulfur) Thousands of different types and function Control the rate (speed) of reactions Cell processes Used to form bone & muscle Move (transport) substances in/out of a cell Fight disease Proteins Building blocks of proteins are called amino acids 2 amino acids attach using a peptide bond Can combine & make a long chain of amino acids called a polypeptide. Proteins The function of a protein is determined by its shape Long chains of amino acids (polypeptide chains) get folded into specifics shapes Examples include transport proteins and enzymes Proteins The number, type & sequence of the amino acids determine what the protein is and its function Sequence of amino acids 🡪 Primary structure of protein Folding and twisting 🡪 Secondary structure Secondary structure folds more 🡪 tertiary structure Tertiary structure determines the function 2 or more tertiary can combine to make its quaternary structure Protein Structure