Chapter 2 Review

matter

anything that occupies space and has mass

elements

cannot be created or broken down

4 elements that make up the bulk of the body

oxygen, carbon, hydrogen, nitrogen

atoms

smallest quantity of an element that retains the unique properties of that element

bond

electrical attraction that holds atoms in the same vicinity (an energy relationship not a physical connection)

molecule

2 identical atoms

compound

2 different atoms

types of chemical bonds

ionic, covalent, hydrogen

ionic bond

a bond between a cation and an anion, made up of atoms that gain or lose electrons (ex. NaCl)

covalent bond

share electrons in a mutually stabilizing relationship (can be polar or non-polar)

hydrogen bond

always includes hydrogen that is already part of another polar molecule

polar covalent bond

unequal sharing of electrons

non-polar covalent bonds

equal sharing of electrons

synthesis reaction

joining of components to create a larger molecule (anabolism)

decomposition reaction

breakdown of a molecule into its constituent parts (catabolism)

exchange reaction

both synthesis and decomposition occur

water

70% of the human body, heat sink, component of liquid mixtures, cushion and lubricant

solution

solvent that dissolves a solute (homogeneous = evenly distributed solute molecules)

polar molecules

hydrophilic, easily dissolve in water

non-polar molecules

hydrophobic, do not dissolve in water

colloids

somewhat like a heavy solution, solute is in tiny clumps that make the liquid opaque and don’t settle (ex. milk)

suspensions

heavier substance is suspended temporarily in a liquid, settles over time (ex. water and sand)

dehydration synthesis

one reactant gives up a hydrogen atom, the other gives up an OH and water is released as a byproduct

hydrolysis

molecule of water breaks the bonds of the compound, H and OH released

salts

formed from ionic compounds, dissociate completely in water (electrolytes = conduct electricity)

acids

release H+ ions in a solution (ex. HCl), low pH

bases

absorb H+ ions present in a solution (ex. HCO₃^- and NH₃), high pH

pH

measures the concentration of H+ in a solution (more acidic = more H+ present)

buffer

solution of weak acid and its conjugate base (prevents large changes in pH)

carbohydrates

made up of C, H, and O; main function is to provide energy; can be mono, di or polysaccharides; monomer is the smallest unit that makes up polymers

lipids

mostly made of C and H, sometimes O and P; all are hydrophobic (form emulstions in H₂O); can be triglycerides, phospholipids or steroids

saturated fatty acids

no double carbon bonds, solid at room temp (ex. butter)

unsaturated fatty acids

contain one double carbon bond, liquid at room temp (ex. oil)

triglycerides

found in body tissue, source of fuel

phospholipids

hydrophilic head and hydrophobic tail, important to the structure of cell membranes

steroids

cholesterol, building block for hormones

proteins

amino acids linked by peptide bonds, provide support and protection; polymer made of amino acids that contain nitrogen; made through dehydration synthesis, shape is essential to function

amino acids

has an amino group and a carboxyl group, there are 20 different types

nucleic Acids

differ in their type of pentose sugar (made up of nucleotides)

nucleotides

have a phosphate group + pentose sugar + nitrogen containing base (can become DNA or RNA)

DNA

double stranded coil to form double helix, strictly located in the nucleus (Adenine + Thymine and Cytosine + Guanine)

RNA

single stranded sugar-phosphate backbone, mainly outside the nucleus and have Uracil instead of Thymine

ATP

ribose sugar + adenine base + 3 phosphate groups, high energy compound (when a phosphate group is taken it becomes and ADP + Pi)