Honors Bio: Biodiversity and Life

Textbook readings, HONC modeling, properties of water

biology

the study of life

cells

smallest unit of life (all living things composed of cells)

adaptation and evolution

changes (mutations) in genes in response to survival needs

response to stimuli

ability to respond to changes in environment

growth and development

differences in size, appearance, and shape from child to adult changes

organization

everything in life is divided into structured levels

emergent properties

new properties—lacking from the previous level, that arise

reproduction

ability to reproduce

energy

intake and processing of energy

homeostasis

maintenance of internal environments (pH, temp, etc)

atom

smallest unit of matter, smallest form of element that retains its properties

molecule

two or more atoms that are covalently bonded

organelle

functional structures inside cells

tissue

group of similarly focused cells

organ

group of tissue working together

organ system

multiple organs working together

organism

organ systems working to form individual

species

unique kind of individual

population

every member of a species in a specific area

community

all populations in specific area

ecosystem

community and its interacting environment

biosphere

all ecosystems (all life and their environments)

matter

something that takes up space and has volume

element

substances that cannot be broken down further by natural means

compound

substance with fixed ratios and emergent properties

trace elements

elements found in minuscule amounts

proton

subatomic particle with singular positive charge

electron

subatomic particle with singular negative charge

neutron

subatomic particle with no charge

nucles

center of an atom (proton and neutrons)

atomic number

number of protons in an atom’s nucleus

mass number

sum of the number of proton and neutrons

atomic mass

weight of an entire atom (**electron has negligible weight)

octet rule

atoms want 8 electrons/max number of electrons (for H and He) to be stable

ion

atom with more or less electrons in proportion to protons

isotope

atoms with differing amount of neutrons

radioactive isotope

isotope with unstable nucleus that emits random waves of energy and particles as it decays

radioactive tracer

a radioactive substance that can be used to visualize certain parts of the body by machines

electron shell

levels at specific volumes from the nucleus that holds a certain number of electrons

orbital

areas within shell that holds a max of two electrons

valence shell

outermost shell of an atom

valence

measure of an atom’s potential reactivity

chemical bond

attraction between atoms caused by movement of electrons (transferred or shared)

ionic bond

when a nonmetal and metal transfer electrons so tha attraction between ions of opposite charge

what are the two ways ionic bonds are drawn?

bohr model, lewis dot (arrows represent movement of electrons, charge signs must be detailed)

hydrogen bond

weak attraction between hydrogen and O, N or F atom (all more electronegative than hydrogen)

covalent bond

when two nonmetals share a pair of electrons with each other

what are the three ways covalent bonds can be drawn?

structural model, bohr model (pair of electrons encompassed by both valence shells), lewis dot (pair of electrons square in middle of two symbols)

electronegativity

measure of how much an atom attracts other covalently shared electrons

non polar covalent bond

covalent bond with atoms of equal or approximate electronegativity allowing the electrons to be shared equally

polar covalent bond

covalent bond with atoms of differing electronegativity sharing the electrons unequally

molecular formula

represents specific amount of each atom (subscript) and what type of element (chemical symbol)

electron distribution diagram

shows how each atom in a chemical bond completes their valence shell

structural formula

representation of covalent bonds (lines) with chemical symbols, mimics actual molecular shape

space-filling model

most realistic, color coded sphereical representation of molecules

bohr model

molecular modeling involving detailing of the nucleus and each electrons shell (in cardinal directions)

lewis dot

quicker way to represent an atom’s valence electrons by dots in cardinal directions around chemical symbol

who was henry cavendish?

first to recognize hydrogen gas as individual substance, identify composition of water, comparative density of hydrogen & gases to air, accurately determined atmospheric composition, density of the earth, other laws

what was previously assumed before cavendish of water?

water itself was a singular element instead of being made up of two

what is the most important property of water?

water forms hydrogen bonds with itself

how is water a polar molecule?

the oxygen is more electronegative, so it has a more negative charge, also giving the two hydrogens a slightly positive charge

what type of bonds are in water?

covalent bonds, in V shape

four life giving principles

expansion when freezing, universal solvent, adhesion & cohesion, temperature regulation

expansion when freezing

water molecules are spread as they are spaced evenly (in contrast with organization of liquid state’s hydrogen bonds), AIR POCKETS form

why does ice float in water?

ice is less due to the expansion taht occurs when freezing, making it less dense (tightly packed) than the water and allowing it to float

what is important about ice?

it insulates marine life when freezing over bodies of water, it forms top → down, floats in water

universal solvent

polar or ionic molecules are able to overpower the water’s hydrogen bonds, and instead hydrogen bonding with the water itself

hydrophyllic

polar substance that breaks cohesive hydrogen bonds in water, allowing water to dissolve it

hydrophobic

non polar substances that cannot break cohesive hydrogen bonds, and are repelled or pushed out by cohesive forces

cohesion

water’s tendency to stick to itself through hydrogen bonds between the hydrogen and oxygen of separate molecules **strongest cohesion

adhesion

water’s tendency to stick to other surfaces through hydrogen bonds between the hydrogen and the polar surface

capillary action

the gravity-defying ability of water through adhesion to a surface, than cohesion with adhered water molecules that PULLS water up the surface

temperature stabilization

more energy is needed to break/male hydrogen bonds, and therefore feel temp changes (excitement or calming of molecules)

heating

more energy most be absorbed to break hydrogen bonds/excite water molecules (absorption of heat)

cooling

more energy needed to create hydrogen bonds/calm water molecules (release of heat)

how does water’s temp regulation help?

oceans act as massive heat sinks and regulate the global climate, land bodies of water are warmer in the winter → cooler in the summer, 80-90% of cells made of water, sweat evaporation regulates body temp, ice forms slowly

ionization of water

one in a million water molecules dissociate (H20 → H+ and OH-); pH=10^7 => 7

pH scale

logarithmic measure of H+ ion concentration in PURE water (1 = acidic, 7 = neutral, 14 = basic)

how do you adjust pH?

to make things more acidic, you add H+ ions, to make things more basic you add OH- receptors (will accept H ions to make water, extra receptors turn pure water basic)

buffer

chemical in body that negates effect of acid or base (accepting H+ or OH- ions)

what is important about pH?

slight changes in body pH could be fatal, so strict balance must be maintained (7.35-7.45)