Chemical basis of life (chapter 2)

• Ionic bonding: atoms held together by exchanging electrons
• Covalent bonding: two or more atoms held together by an electron pair
• Single covalent: when two atoms share one pair of electrons
• Double covalent: two atoms share 4 electrons
• Nonpolar covalent: electrons shared equally because nuclei attract the electrons equally
• Hydrogen bond: occurs when the positively charged Hydrogen of one molecule is attracted to the negatively charged Oxygen, Nitrogen, or Flourine of another molecule
• Energy: the capacity to do work
• Potential energy: energy stored in chemical bonds; energy that could do work if it were released
• Kinetic energy: does work and moves matter
• Mechanical energy: energy resulting from the position or movement of objects
• Chemical energy: form of potential energy in the chemical bonds of a substance
• Heat energy: energy that flows between objects at different temperatures
• Activation energy: minimum energy reactants must have to start a chemical reaction
• Catalysts: substances that increase the rate of reaction without being permanently changed or depleted
• water is 50-60% of body, 92% of blood
• 7.4 pH is physiological normal
• Carbs: composed of carbon, hydrogen, and oxygen; energy source and structure
• Lipids: relatively insoluble in water
• Proteins: composed of carbon, hydrogen, oxygen, and nitrogen
• Nucleic acids: DNA & RNA
• Monosaccharides: simple sugars
• Disaccharides: 2 monosaccharides bound together through dehydration reaction (e.g., sucrose, maltose)
• Polysaccharides: starch and cellulose formed by plants; starch used as a source of monosaccharides, cellulose acts as fiber in the diet
• Lipids: function in protection, insulation, and energy source
• Triglycerides: composed of glycerol and fatty acids
• Saturated fats: contains all single bonds in the carbon chain, producing a more rigid structure
• Unsaturated fats: contains one (mono) or more (poly) double bonds in the carbon chain, producing a more relaxed structure
• Trans fats: unsaturated fats artificially altered to be more saturated,
• Phospholipids: polar (hydrophilic) at one end, nonpolar (hydrophobic) at the other
• lipid Steroids: cholesterol component of cell membranes, precursor for steroid hormones
• Proteins: amino acids are building blocks of protein; peptide bonds formed between amino acids during protein synthesis
• Nucleic acids (DNA, RNA)
• DNA: composed of 2 strands of nucleotides, A&T, G&C complementary, form a double helix
• ATP: Adenosine triphosphate, energy currency of the body