AP Classroom Units 1-3

these are just the things I didn't remember well/lynch didn't teach (well)

chemical structure of H₂O

one O₂ covalently bonded to two H₂

how does water structure result in polarity

oxygen is more electronegative than hydrogen, resulting in polarity (electrons are shared unequally)

polarity

the difference in atomic electronegativity causes a molecule to have a positive or negative charge

how does water’s polarity result in cohesion and adhesion through hydrogen bond interactions

polarity allows molecules to form hydrogen bonds when oppositely charged regions of two molecules interact

hydrogen bond

a weak bond/interaction between the negative and positive regions of two molecules

what chemical characteristics of water result from it’s cohesive and adhesive properties

• surface tension

• high solvency

• capillary action

cohesion

hydrogen bonds between molecules of the same type

adhesion

hydrogen bonds between molecules of different types

surface tension

a result of increased hydrogen bonding at the surface of water

life’s dependence on surface tension

things like aquatic plants can reset on water and have greater access to sunlight

life’s dependence on water’s high solvency

allows for easy access to dissolved nutrients (plants)

life’s dependency on ice’s ability to float

aquatic organisms can live in places where water freezes

life’s dependency on water’s high heat capacity

• water does not change temperature quickly

• this allows for thermoregulation of organisms

life’s dependency on capillary action

• this is the effect shown when water moves up a paper towel

• this is how plant roots function

why do living systems require a constant input of energy

growth, reproduction, maintenance of organization

why must living systems exchange matter with the environment

in order to get the building blocks necessary to make new molecules

role of carbon in building biological macromolecules

• used to build all macromolecules

• stores energy

• forms cells

what is the directionality of the subunits of proteins

• amino acids have an amino terminus (NH₃) and a carboxyl terminus (COOH)

• polypeptides are built by additions to the carboxyl terminus (covalent bonds)

similarities between DNA and RNA

• both are made of nucleotide subunits connected by covalent bonds

• 3’ and 5’ ends

• nucleotides are made of sugar, phosphate, nitrogenous base

differences between DNA and RNA

• type of sugar

• uracil vs thymine

• number of strands

how do ribosomes reflect the common ancestry of all known life

• not enclosed by membranes

• present in all known life

how do large molecules enter the cell

endocytosis - cells take in macromolecules and particulate matter by forming new vesicles derived from the plasma membrane

how do large molecules exit the cell

exoyctosis - internal vesicles fuse with the plasma membrane to secrete large molecules

how do membranes become polarized

movement of ions across the membrane

water potential

• the tendency of water to move by osmosis

• calculated from pressure potential and water potential

• more negative means an increased likelihood of moving to the area

how do internal membranes facilitate cellular processes

they minimize competing interactions and increase surface area where the reaction is occurring

similarities and differences between compartmentalization in prokaryotic and eukaryotic cells

same: external plasma membranes

different: eukaryotes have membrane bound organelles, and prokaryotes only have regions

types of control groups

negative and positive

role of the positive control group

• confirms a known effect

• exposed to a treatment with a known effect

• not exposed to an experimental treatment

role of the negative control group

• confirm results in the absence of a treatment

• not exposed to any treatment

products of the Krebs Cycle

CO₂, ATP, NADH, FADH₂