mastering biology chapter 2

polarity

-forces between molecules that determine how they group together and interact -creates molecules with charged ends

electronegativity

-the tendency of an atom to attract electrons in the formation of an ionic bond

ion

-charged atom or molecule -positive (+) or negative (-)

ionic bond

-formed by the transfer of electrons -one atom loses an electron to form a positive ion and the other atom gains an electron to form a negative ion -held together by charge differences

atom

basic unit of a chemical element

molecule

-2 or more atoms held together by covalent bonds -smallest unit of a chemical compound that can take part in a chemical reaction

covalent bond

equally shared pair of outer-shell electrons between 2 atoms

octet

tendency of an atom to have 8 valence electrons

double covalent bond

-2 shared pairs of electrons between atoms -limits atoms to a plane

triple covalent bond

-3 shared pairs of electrons between molecules -limits atoms to a line

polar attraction

weak attraction between 2 polar molecules

nonpolar attraction

weak attraction between nonpolar molecules caused by neighboring molecules disturbing each other's electron movements

polar covalent bond

-bond between 2 different atoms, one positive and one negative -results from the unequal sharing of electrons

nonpolar covalent bond

-atoms share electrons equally -no charge separation to the molecule

water molecule

-can hydrogen bond to 4 other water molecules -contains positive (H+) & negative (O-) poles (different electronegativity values) -held together by polar covalent bonds because O- in water molecules pulls harder on the electrons -has a slightly negative charge near O and a slight positive charge near H -many properties occur due to its attraction among polar molecules

hydrogen bond

-holds water molecules together -H+ of one water molecule is attracted to an O- atom of another water molecule -form, break, and reform with great frequency because they are weak

hydrogen ion (H+)

hydrogen atom that gains or loses an electron

dissociation of water molecules

process in which a hydrogen ion shifts from one water molecule to another

hydroxide ion (OH-)

-water molecule that lost a hydrogen ion -has an extra electron -negatively charged

hydronium ion (H3O+)

-water molecule that gains a hydrogen ion -has an extra proton -positively charged

cohesion

-sticking together of 2 like molecules (water) -caused by the attraction of opposite charges (polarity)

adhesion

-sticking together of 2 unlike molecules (water and another substance) -caused by the attraction of opposite charges (polarity)

capillary action

the ability to flow upward against the force of gravity due to cohesion and adhesion

surface tension

-the attraction between water molecules at the surface -measure of the force required to stretch or break the surface of a liquid

specific heat

-amount of heat that must be absorbed or lost before a substance changes temperature -water resists temperature change due to it absorbing energy by disrupting hydrogen bonds before evaporation can occur

heat of vaporization

-cooling of a surface as a liquid evaporates -while sweating, fastest-moving water molecules break every hydrogen bond and escape, carrying away the heat

density

-measure of how compact atoms or molecules are within a substance -amount of mass in a given volume -ice is less dense than water because the molecules in its lattice are further apart

solvent

-liquid that dissolves the solute -water is a universal solvent due to its polarity

solute

-particle or liquid that gets dissolved in the solvent

solution

mixture in which a substance dissolves into another

compound

a substance formed by chemically combining two or more elements

mixture

a substance consisting of two or more substances mixed together

suspension

mixture in which the particles are spread throughout the liquid without dissolving in it

homogeneous

uniform throughout a mixture

heterogeneous

not uniform throughout a mixture

pH scale

-measurement of the concentration of hydrogen ions -logarithmic (powers of 10)

acid

-increases hydrogen ion concentration -pH less than 7

base (alkali)

-increases hydroxide ion concentration -pH more than 7

neutral

-equal concentration of H+ and OH- -pH of 7

buffer

-accepts H+ when they are in excess and donates H+ when their concentration drops in a solution -helps maintain pH of bodily fluids (homeostasis)

domain

-level of classification larger than a kingdom -3 main domains

Bacteria/Archaea Domain

contains prokaryotic organisms (found in the Monera Kingdom)

Eukarya Domain

contains eukaryotic organisms (found in the Protista, Plantae, Fungi, or Animalia Kingdoms)

biological hierarchy

-atom -molecule -organelle -cell -tissue -organ -organ system -organism -population -community -ecosystem -biome -biosphere

organelle

cellular structure specialized to perform a distinct function

cell

-Basic unit of structure and function in all living things -Compose unicellular/multicellular organisms -First level of life

tissue

material in plants/animals consisting of specialized cells and their products

organ

-self-contained -does a specific job in an organism -made up of certain tissues

organ system

group of organs that work together to perform one or more functions

organism

an individual animal, plant, or single-celled life form

population

all organisms that constitute a specific species in a specified habitat

community

all the populations in a given area

ecosystem

a system formed by the interaction of a community (biotic factors) with their physical environment (abiotic factors)

biome

naturally occurring community of flora & fauna occupying a major habitat

biosphere

parts of the land, sea, & atmosphere in which organisms are able to live

characteristics of life

-universal genetic code -response to stimuli -growth & development -energy processing -evolutionary adaptation -reproduction -homeostasis -cells

universal genetic code

-All organisms use DNA molecules to carry genetic information from generation to generation -DNA & RNA store information necessary to live, grow & reproduce

response to stimuli

Organisms adjust & respond to changes in their internal/external environments

growth

increase in size

development

process of change during an organism's life to produce a more complex organism

energy processing

-The use of chemical energy to power an organism's activities & chemical reactions -Organisms obtain & use materials/energy

metabolism

-All the chemical reactions within an organism -Catabolism and anabolism

evolutionary adaptation

-An accumulation of inherited characteristics that enhance an organisms' ability to survive & reproduce in specific environments -Over generations, living things evolve

reproduction

-The reproduction of offspring through sexual/asexual processes -All living things make new similar living things

asexual reproduction

-Type of reproduction in which a single parent reproduces by itself -Produces offspring exactly the same as itself

sexual reproduction

-Type of reproduction in which cells from 2 parents unite to form the first cell of a new organism -Combination of information from both parents results in diversity

Homeostasis

-Process by which organisms maintain stable conditions during changes in the environment -Ensures that an organism's body functions at optimal condition

microscope base

Supports the microscope.

arm

Used to carry the microscope.

stage

Platform where the slide with the specimen is placed.

stage clips

Holds the slide in place on the stage.

eyepiece

-Magnifies the image for the viewer. -Contains the ocular lens

revolving nosepiece

Contains the objective lenses -Rotates to allow the user to switch between different objective lenses.

Objective lenses

Low-, medium-, and high-power lenses that further magnify the specimen at different intensities.

Coarse adjustment knob

Large knob used for focusing the image under low-power (general focusing).

Fine adjustment knob

Smaller knob used for focusing the image with the medium- and high-power objectives (fine-tuning).

Diaphragm

Controls the amount of light that passes through the specimen.

Light source

Provides light for viewing the specimen.

control group

-does not receive the variable -provides a baseline for the conclusion of the experiment

experimental group

receives the variable that the researcher manipulates

variable

-any factor, trait, or condition that can exist in differing amounts or types -only one variable per experiment in order to easily determine how the change affected the result

independent variable

-The experimental factor that is manipulated -Placed on the x-axis

dependent variable

-Variable directly affected by the independent variable -Placed on the y-axis

constant

-values that do not change during experiments -provides a baseline for the conclusion of an experiment

total magnification

power of the objective (4x, 10x, 40x) times the power of the eyepiece (10x)