Chapter 1: Chemistry Flashcards
atom/molecule
Neutrons, protons, and electrons/group of 2 or more atoms held together by chemical bonds (chemical bonds due to electron interactions)
electronegativity
Ability of an atom to attract electrons (determines kind of bond that forms)
bond types
- Ionic=transfer of electrons from one atom to another (different electronegativities)
- Covalent=sharing of electrons between atoms (similar EN-)
Nonpolar= equal sharing of electrons (identical EN)
Polar=unequal sharing of electrons (different EN and dipole formation) - Hydrogen=weak bond between molecules with a hydrogen attached to a highly EN atom and is attracted to a negative charge on another EN molecule (N,O,F)
excellent solvent/hydrophilic/hydrophobic
dipoles of H2O break up charged ionic molecules. Hydrophilic=water loving… dissolve in water. Hydrophobic= water fearing … do not dissolve in water.
high heat capacity
degree in which a substance changes temp in response to gain/loss of heat (changes temperature very slowly with changes in heat content). For example, the temperature of large water body are very stable in response to temp changes of surrounding air; must add large amount of energy to warm up water. High heat of vaporization as well.
ice floats
water expands as it freezes, become less dense than its liquid form (H-bonds become more rigid and form crystal that keeps molecules separated).
cohesion/surface tension
attraction between like substances due to H-bonds; strong cohesion between H2O molecules produces a high surface tension (water surface that is firm).
adhesion
attraction of unlike substances (wet finger and flip pages); capillary action: ability of liquid to flow without external forces (e.g. against gravity).
organic molecules
characterized by carbon atoms. Macromolecules form monomers (1 unit) which forms polymers (series of repeating monomers). 4 of carbon’s 6 electrons are available to form bond with other atoms.
functional groups
particular cluster of atoms, gives molecules unique properties such as acidity and polarity
hydroxyl (OH)
polar and hydrophilic
carboxyl (COOH)
polar, hydrophilic, weak acid
amino (NH2)
polar, hydrophilic, weak base
phosphate (PO3)
polar, hydrophilic, acid (sometimes shows as PO4)
carbonyl (C=O)
aldehyde (H-C=O)
ketone (R-C=O)
polar and hydrophilic
methyl (CH3)
nonpolar and hydrophobic
carbohydrates: monosaccharide
single sugar molecule (e.g. glucose and fructose). Alpha or beta based on position of H and OH on first (anomeric) carbon (OH down=alpha, OH up=beta).
disaccharide
two sugar molecules joined by a glycosidic linkage (joined by dehydration/condensation=loss of water). E.g. sucrose (glu+fru), lactose (glu+gal), maltose (glu+glu)
polysaccharide
series of connected monosaccharides; polymer. Bond via dehydration synthesis, breakdown via hydrolysis (addition of water).
starch
polymer of a-glucose molecules; store energy in plants
glycogen
polymer of a-glucose; store energy in animal cells
cellulose
polymer of b-glucose; structural molecules for cell walls in plants and wood
chitin
polymer similar to cellulose; but each b-glucose has a nitrogen-containing group attached to ring. Structural in fungal cell walls (also exoskeletons of insects)
lipids and their functions
hydrophobic molecules. Fxns: insulation, energy storage, structural (cholestrol and phospholipids in membranes), endocrine
triglycerides (triglycerols)
three fatty acid chains attached to a glycerol backbone
saturated triglycerides
no double bonds (bad for health, saturated=straight chain=stack densely and form fat plaques=solid at room temp)
unsaturated
double bonds (better for health, unsaturated=double bonds cause branching=stack less dense=liquid at room temp)