chapter 2

• Protein shape plays a crucial role and it means for a protein to be denatured.
• The components of triglycerides are fatty acids and glycerol.
• RNA and DNA have different roles in the cell.
• The structures of polysaccharides, proteins, and nucleic acids can be compared and contrasted.
• The chemistry of life is the study of the elements that make up living organisms, including carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.
• An element is a substance that cannot be broken down by chemical means into other substances.
• Living things such as this newt and plant are mostly composed of six elements: carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.
• The periodic table lists all known elements.
• Each box on the periodic table shows one element, including the element’s full name and the element’s one or 2 letter symbol.
• The periodic table shows the properties of elements, including each element’s atomic number and atomic weight.
• An atom is the smallest piece of an element that retains the characteristics of the element.
• An atom is composed of three smaller particles: protons, neutrons, and electrons.
• Protons are positively charged, neutrons are neutral, and electrons are negatively charged.
• An element’s atomic number indicates how many protons are in each atom of that element.
• An atom’s mass number is the total number of protons and neutrons in its nucleus.
• Two elements with moderately different electronegativities will likely form nonpolar covalent bonds.
• The mass number of the carbon atom shown below is 12.
• Polar covalent bonds form when atoms have different electronegativities.
• Some atoms have such different electronegativities that one atom completely pulls an electron away from the other, forming an ionic bond.
• Examples of covalent bonds include H-H bond in H2 molecule and O-H bond within water molecule.
• Covalent bonds are characterized by two atoms sharing pairs of electrons, and are strong but nonpolar.
• Hydrogen bonds give water its emergent properties.
• The slight positive charge on the hydrogen atom of one water molecule attracts the slight negative charge on the oxygen of an neighboring water molecule, forming a hydrogen bond.
• Ionic bonds are strong but break easily in water.
• Examples of ionic bonds include Sodium chloride (NaCl) and Calcium fluoride (CaF2).
• Electronegativity can be used to predict bonding types.
• Water is held together by polar covalent bonds.
• Hydrogen bonds pull water molecules close to each other, giving water a collection of unique properties and being very important in protein and DNA structure.
• Polarity in water molecules creates hydrogen bonds.
• The atom that loses an electron becomes positively charged, and the atom that gains an electron becomes negatively charged, attracting the atoms to each other and forming an ionic bond.
• An isotope is any of these different forms of the element.
• Two elements with similar electronegativities will likely form nonpolar covalent bonds.
• Hydrogen bonds form between adjacent molecules or between different parts of a large molecule, are weak, and give water its emergent properties.
• In an ionic bond, both atoms achieve full outer energy shells, and there are no longer vacancies in either atom.
• Monosaccharides are simple sugars; they are the monomers that make up larger carbohydrates.
• Proteins are the “workers” of cells; they do almost everything.
• There are 20 different amino acids in nature.
• Dehydration synthesis binds two amino acids together, forming a dipeptide.
• A long chain of amino acids is called a polypeptide.
• Cellulose, starch, and glycogen are examples of polysaccharides.