AP Bio Unit 1

matter

anything that takes up space and has mass

element

A substance that cannot be broken down into other substances by chemical reactions

compound

a substance consisting of two or more different/same elements combined in a fixed ratio

essential elements

elements needed to survive and reproduce(20-25%)

CHON

96% of living matter

trace elements

required by an organism in very small quantities

atomic number

the number of protons in the nucleus(unique to each)

atomic mass

number of protons and neutrons in the nucleus (averaged over all isotopes)

isotopes

same number of protons and different number of nuetrons

radioactive isotopes

nucleus decays spontaneously, giving off particles and energy

group

elements in the same vertical column; same number of valence electrons

period

elements in the same horizontal row; same total number of electron shells

bohr model

shows electrons orbiting the nucleus of an atom

1st shell

holds 2 electrons

2nd shell

holds 8 electrons

3rd shell

holds up to 18 electrons(happy with 8)

lewis dot model

Simplified Bohr diagrams; does not show energy levels; only shows electrons in the VALENCE SHELL (outermost shell); electrons are placed around the element symbol

chemical bonds

attraction between two atoms, resulting from the sharing or transferring of valence electrons

octet rule

elements will gain, lose, or share electrons to complete their valence shell and become stable(like noble gases)

electronegativity

a measure of an atom's ability to attract electrons to itself

covalent bonds

when two or more atoms share electrons(usually between two nonmetals)

single bond

one pair of shared electrons

double bond

two pairs of shared electrons

triple bond

three pairs of shared electrons

nonpolar covalent bond

electrons are shared equally between two atoms

polar covalent bond

electrons are NOT shared equally between two atoms; determine by electronegativity of atoms

ionic bonds

the attraction between oppositely charges atoms(ions); usually between metal and nonmetal; metal transfers electrons to nonmetal

cation

positively charged ion(metal)

anion

negatively charged ion(nonmetal)

hydrogen bonds

the partially positive hydrogen atom in one polar covalent molecule will be attracted to an electronegative atom in another polar covalent molecule

FON

most electronegative elements

intermolecular bond

bond that forms between molecules

water

most abundant molecule in living organisms. only substance on Earth that naturally occurs in all 3 physical states of matter

polarity (property of water)

unequal sharing of the electrons make water a polar molecule. since oxygen has a higher electronegativity than hydrogen

cohesion (property of water)

attraction of molecules for other molecules of the same kind. responsible for surface tension. allows for the transport of h2o and nutrients against gravity in plants

surface tension

property allowing liquid to resist external force

adhesion (property of water)

the clinging of one molecule to a different molecule. occurs due to the polarity of h2o. in plants this allows water to cling to the cell walls to resist the downward pull of gravity

capillary action (property of water)

the upward movement of water due to the forces of cohesion, adhesion, and surface tension. occurs when adhesion is GREATER than cohesion. important for transport of water and nutrients in plants

high specific heat (temp control-property of water)

h2o resists changes in temperature by hydrogen bonds. heat must be absorbed to break hydrogen bonds, but heat is released when hydrogen bonds form

importance of high specific heat

moderates air temperature, stabilizes ocean temperature, organisms can resist changes in their own internal temperature

evaporative cooling (temp control-property of water)

water has a high heat of vaporization. molecules with the highest kinetic energy leave as gas

Importance of evaporative cooling

Moderates earths climate, stabilizes temperature in lakes and ponds, prevents terrestrial organisms from overheating, and prevents leaves from becoming too warm in the sun

density (property of water)

floating ice. as water solidifies it expands and becomes less dense. this occurs due to the hydrogen bonds, when cooled h2o molecules move too slowly to break the bonds, and hydrogen bonds cause water molecules to form a crystalline structure

solvent (property of water)

dissolving agent in a solution

type of solvent water is

versatile. its polar molecules are attracted to ions and other polar molecules it can form hydrogen bonds with. (example: water can interact with sugars or proteins containing many oxygen and hydrogen. water will form hydrogen bonds with the sugar or protein to dissolve it)

solution

A homogeneous mixture of two or more substances

solute

A substance that is dissolved in a solution.

ionic compounds

compounds composed of cations and anions. the partially negative oxygen in water will interact with a positive atom. the partially positive hydrogen in water will interact with a negative atom. dissolves ions

evaporation

liquid to gas (endothermic)

condensation

gas to liquid (exothermic)

depostition

gas to solid (exothermic)

sublimation

solid to gas (endothermic)

freezing

liquid to solid (exothermic)

melting

solid to liquid (endothermic)

transpiration

evaporation from the surface of plants

4*C

water is most dense

metabolism

All of the chemical reactions that occur within an organism

metabolic pathways

series of chemical reactions that either build complex molecules or break down complex molecules. controlled by enzymes

catabolic pathways

pathways that release energy by breaking down complex molecules into simpler compounds

anabolic pathways

pathways that consume energy to build complicated molecules from simpler ones

energy

the ability to do work

kinetic energy

energy associated with motion

thermal energy

type of kinetic energy. associated with the movement of atoms or molecules

potential energy

stored energy

chemical energy

potential energy available for release in a chemical reaction

thermodynamics

The study of energy transformations that occur in a collection of matter. the laws apply to the universe as a whole

1st law of thermodynamics

Energy cannot be created or destroyed. energy can be transferred or transformed

2nd law of thermodynamics

energy transformation increases the entropy (disorder) of the universe. during energy transfers or transformations, some energy is unusable and often lost as heat

free energy

energy available to do work. used to determine the likelihood of reactions in organisms, or if the reactions are energetically favorable

free energy change of reactions

determine whether or not the reaction occurs spontaneously. causes an increase in entropy and is moving towards a chemical equilibrium

exergonic reaction

reactions that release energy. example: cellular respiration (reaction is spontaneous). drive the formation of ATP

endergonic reaction

reactions that absorb energy. example: photosynthesis (reaction is not spontaneous, absorb free energy). driven by hydrolysis of ATPorg

Disequilibrium

if a cell reaches equilibrium it is "dead" therefore in a cell there is always this

coupling

The extent to which subsystems depend on each other.

mechanical (type of work cells perform)

movement (beating cilia, movement of chromosomes, contraction of muscle cells)

transport (type of work cells perform)

pumping substances across membranes against spontaneous movement

chemical (type of work cells perform)

synthesis of molecules (building polymers from monomers)

ATP

(adenosine triphosphate) molecule that organisms use as a source of energy to perform work. couples exergonic reactions to endergonic reactions to power cellular work. organisms obtain energy by breaking the bond between the 2nd and 3rd phosphate in a hydrolysis reaction

Phosphorylation

the released phosphate moves to another molecule to give energy

Hydrolysis of ATP

releases energy and breaks off 3rd phosphate to create ADP

organic chemistry

branch of science dealing with the element carbon and its many properties

organic molecules

carbohydrates, lipids, proteins, nucleic acids

carbon

tetravalent (4 valence electrons). can bone wit 4 other molecules allowing it to act like an intersection in the building of an organic molecule

inorganic compounds

no carbon-hydrogen bonds

itself, hydrogen, oxygen, nitrogen

common bonding partners of carbon

alkanes

single bonded hydrocarbons. have most hydrogen. saturated. end in -ane

alkenes

double bonded hydrocarbons. unsaturated. end in -ene

alkynes

triple bonded between carbons. unsaturated

hydrocarbons

molecules containing only carbon and hydrogen. use as fuel because of he huge amount of energy stored in these C-H bonds. non-polar and hydrophobic

Type of bond carbon forms

covalent

meth-

1 carbon

eth-

2 carbons

prop-

3 carbons

but-

4 carbons

pent-

5 carbons

hex-

6 carbons

hept-

7 carbons

oct-

8 carbons

non-

9 carbons

dec-

10 carbons