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monomer: monosaccharides (linked together into polysaccharides by dehydration synthesis)
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functions: energy storage (ex: starch in plants and glycogen in animals) and structural support (ex: cellulose for plan cell walls and chitin for exoskeleton of arthropods and cell walls of fungi)
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have a ratio of CH2O (1 carbon: 2 Hydrogen: 1 Oxygen)
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Monomer: amino acids (which are linked by peptide bonds, which are formed by dehydration synthesis between amino and carboxyl groups of adjacent amino acids)
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functions: antibodies, movement, membrane receptors
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Primary Structure- unique sequence of amino acids
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Secondary Structure- folding of the amino acid chain through hydrogen bonds into alpha helices and beta sheets
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Tertiary Structure- overall three-dimensional shape of the protein and often minimizes free energy (hydrophobic interactions, disulfide bridges, H-bonds, ionic bonds)
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Quaternary Structure- arrangement of polypeptides (only occurs in some) ex: hemoglobin
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Denaturation: unfolding of protein structure due to unideal temperature or pH levels
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Monomer: N/A because lipids aren't polymers since they are assembled from a variety of components (ex: fats, oils, waxes, & steroids) ALL HYDROPHOBIC
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Function: energy storage, protection, insulation, phospholipid bilayer
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Fats (aka triglycerides): made of a glycerol molecule and 3 fatty acid molecules (fatty acids: nonpolar hydrocarbon chains)
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Saturated Fatty Acids: no double bonds between carbons, pack solidly at room temp, max number of hydrogens, commonly produced by animals)
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Unsaturated Fatty Acids: have some carbon double bonds which result in kinks, liquid at room temp, commonly produced by plants)
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Phospholipids have a hydrophilic (polar) head that includes a phosphate group and 2 hydrophobic fatty acid tails
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Steroids have a carbon skeleton of 4 rings that are fused together (ex: cholesterol in animal cell membranes, and estrogen and testosterone)
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Monomer: nucleotides
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Function: genetic info that codes for amino acid sequences
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DNA and RNA
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Nucleotides are made of 3 parts: nitrogenous base, pentose (5-carbon) sugar (deoxyribose in DNA and ribose in RNA), and the phosphate group (PO4)
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Covalent Bonds
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Nonpolar covalent bonds: electrons are shared equally
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polar covalent bonds: one atom has a greater electronegativity --> unequal sharing of electrons
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Ionic Bonds
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chemical bonds formed by the attraction of oppositely charged ions
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ex: table salt
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Hydrogen Bonds
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weak chemical interactions that form between a partial positively charged hydrogen atom of one molecule and the strong electronegative oxygen or nitrogen of another molecule
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ex: hydrogen bonds between water
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Van der Waals interactions
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very weak, short-lasting connections that are a result of asymmetrical distribution of electrons within a molecule
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contribute to the 3d shape of molecules
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pH scale: Measures relative acidity and alkalinity of aqueous solutions (between 0 and 14)
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Acids: excess of H+ ions and H+>OH-
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Bases: excess of OH- ions and OH->H+
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Pure water is neutral (pH=7)
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Buffers: substances that minimize changes in pH by accepting H+ from a solution when hydrogen molecules are in excess and donate H+ when hydrogen molecules are depleted
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Buffers are essential in living tissues to minimize pH changes
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Carbonic Acid (H2CO3): important buffer in living systems because it moderates pH changes in blood plasma and the ocean
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Major elements of life are carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus CHNOPS
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All organic compounds contain carbon and most contain hydrogen
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Carbon is unparalleled in its ability to form large, complex, and diverse molecules because it has 4 valence electrons, which means it can form up to 4 covalent bonds (which can be single, double, or triple), and it can form large molecules (which can be chains, ring-shaped, or branched)
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Isomers: molecules that have the same molecular formula but differ in atom arrangement, which can result in molecules that are very different in their biological activities (ex: glucose and fructose)
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Water molecules are polar
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oxygen region of molecule has a partial negative charge and each hydrogen region has a partial positive positive charge
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Hydrogen bonds form between water molecules
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the slightly negative oxygen atom from one water molecule is attracted to the slightly positive hydrogen end of another molecule
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Each water molecule can form up to 4 hydrogen bonds
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Hydrogen Bonds are key to each of the following properties of water and what makes water unique
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Cohesion: Linking of like molecules
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Adhesion: clinging of one substance to another
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Capillary Action: movement of water molecules up very thin xylem tubes and their evaporation from stomata in plants; the water molecules cling to each other by cohesion and to the walls of the xylem tube by adhesion
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Cohesion is responsible for surface tension, which means that water droplets will resist rupture when stress and pressure are added to the system
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Water has a high specific heat. Specific Heat is the amount of heat required to raise or lower the temperature of a substance by 1 degree Celsius. High specific heat makes the temperature of Earth's oceans relatively stable and able to support vast quantities of life
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Water is less dense as a solid than as a liquid, so ice floats, which keeps larger bodies of water from freezing solid, allowing life to exist in bodies of water
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Water is an important solvent (hydrophilic substances are water soluble and hydrophobic substances are nonpolar and don't dissolve in water).
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