Unit 1: AP Bio

qualitative data

descriptions

quantitative data

numbers

null-hypothesis

no association among variables/no difference

alternative-hypothesis

describes relationship between variables/ different of what’s expected

control experiment

experiment group with control group that is unwanted

independent variable

factor manipulated

dependent variable

effect of manipulated factor

standard deviation

amount of variation in your measured data

standard error of mean

how close is calculated mean from data sample to the actual mean

error bars

how variable you data are represented visually on a graph.

measure of statistical significance

may or may not overlap

hydrogen bond

• attracted to another electronegative atom nearby oxygen/ or nitrogen atoms in living cells

• formed when hydrogen atom thats bonded to one electronegative atom

4 properties contributes to earth’s sustainability for life

1) cohesive behavior

2) ability to moderate temperature

3) expansion upon freezing

4) versatility as solvent!

1) cohesion of water molecules

• h-boned to their neighbors

• molecules stay close together because of cohesion

• adhesion (clinging of one substance to another) contributes to transport of water against gravity in plants

1) cohesion results in surface tension

• measure how hard is it to break the surface of liquid

• related to cohesion (H-bonds)

2) moderation of temperature by water

• water absorbs heat and releases stored heat

• water absorb or release heat with slight change in its own temp

• evaporative cooling water helps stabilize temps in bodies or water and organisms

2) water’s high specific heat

• can be traced to hydrogen bonding

• heat is absorbed when h-bonds break, and released when h-bonds form

• keep temp fluctuations within limits that permit life

3)floating of ice on liquid water

h-bonds ice more “ordered”, less dense

4) water: the solvent of life

water is versatile solvent due to polarity, allows it to form hydrogen bonds easily

hydrophilic

substance is one has affinity for water

• ionic compounds: salt is hydrophilic

hydrophobic

substance does not have affinity with water

acids and bases and pH scales

• water dissociation (H+ and OH-) is key in chemistry’s life

• acids increase H+ concentration (less than 7) bases reduce concentration of H+ (pH greater than 7) pH of water (7)