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McGraw-Hill 2nd Ed.

What is homeostasis

the process whereby living organisms regulate their cells and bodies to maintain relatively stable internal conditions

What are the characteristics of living things

1. Cells and Organization
2. Energy use and metabolism
3. Response to environmental changes
4. Regulation and homeostasis
5. Growth and Development
6. Reproduction
7. Biological Evolution


the smallest component of an element having the chemical properties of the element


Two or more atoms held together by covalent bonds.


many molecules bonded together to form a polymer such a polypeptide (carbohydrates, proteins and nucleic acids are examples)


the simplest unit of a living organism, composed of molecules and macromolecules, form larger structures such as membranes


association of many cells of the same type


two or more types of body tissues combined to perform a common function


a living thing that maintains an internal order that is separated from the environment


group of individuals of the same species that occupy the same environment and can interbreed with one another


an assemblage of populations of different species that live in the same place at the same time


the biotic community of organisms in an area as well as the abiotic environment affecting the community


the regions on the surface of the earth and in the atmosphere where living organisms exist

What are the two mechanisms of evolutionary change

Vertical descent and horizontal gene transfer

vertical descent

Progression of changes in lineage (a series of ancestors). Occurs from generation to generation. New species evolve from pre-existing species by accumulation of mutations (natural selection)

horizontal gene transfer

A process in which an organism incorporates genetic material from another organism without being the offspring of that organism

What are the three domains

Bacteria, Archaea, and Eukarya

What are the four kingdoms

animalia, fungi, plantae, and protista


single-celled organisms that lack a nucleus; prokaryotes


Single-celled, no nucleus, Live in harsh conditions


Domain of all organisms whose cells have nuclei, including protists, plants, fungi, and animals


single-celled organism with nuclei (algae, protozoans)


A classification kingdom made up of eukaryotic, multicellular organisms that have cell walls made mostly of cellulose, that have pigments that absorb light, and that supply energy and oxygen to themselves and to other life-forms through photosynthesis


Kingdom of the most complex organisms; multi-cellular, heterotrophic, lack rigid cell walls, mobile, tissues in internal organs, sensory organs, nervous system


the science of naming and classifying organisms

binomial nomenclature

a system for giving each organism a two-word scientific name that consists of the genus name followed by the species name


the complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes


the complete complement of proteins that a cell or organism can make

scientific method

a general approach to gathering information and answering questions so that errors and biases are minimized

Five Stages of Scientific Method

Observations, Hypothesis, Experimentation, Data & Analysis, Accept/Reject Hypothesis


All of the chemical reactions that occur within an organism

biological evolution

Changes in the genetic composition of a population through successive generations.


a broad explanation of some aspect of the natural world that is substantiated by a large body of evidence; makes valid predictions


a proposed explanation for a natural phenomenon based on previous observations or experimental studies

discovery-based science

the collection and analysis of data without the need for a preconceived hypothesis

subatomic particles

protons, neutrons, and electrons

where are subatomic particles located

Protons and neutrons are found in the nucleus and electrons are found in the electron shell


positive- found in nucleus- same number as electrons


neutral- found in nucleus- number can vary


negative- found in orbitals- same number as protons

why are atoms electrically neutral

they have an equal # of protons and electrons


Regions within electron shells where electrons orbit the nucleus

s orbitals

sphere shaped; hold 2 electrons

p orbitals

3 dumbbell/propeller shaped orbitals (2p); can hold 4 pairs of electrons

1st shell

holds a max of 2 electrons; 1 spherical orbital (1s)

2nd shell

1 spherical orbital (2s) & 3 dumbbell shaped orbitals (2p) can hold up to 8 electrons

What is the atomic number of an atom

The number of protons in the nucleus of the atom

atomic mass

total mass of the protons and neutrons in an atom, measured in atomic mass units


Groups of two or more atoms held together by chemical bonds


electrically charged atoms that have gained or lost electrons

ionic bonds

bond formed when one or more electrons are transferred from one atom to another

covalent bonds

A type of strong chemical bond in which two atoms share one pair of valence electrons

polar covalent bond

when two atoms with different electronegativites form a covalent bond; the shared electrons are more likely to be in the outer shell of the atom of higher electronegativity rather than the atom of lower electronegativity

nonpolar covalent bond

a covalent bond in which the bonding electrons are shared equally by the bonded atoms, resulting in a balanced distribution of electrical charge

hydrogen bond

A type of weak chemical bond formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule.

which is the strongest chemical bond

covalent bond

occurs between atoms whose outer electron shells are not full; can share up to three pairs of electrons

covalent bonds

occur because the distribution of electrons around the atoms creates a polarity, or difference in electric charge, across the molecule

polar covalent bond

bonds between atoms with similar electronegativities

nonpolar covalent bonds


net positively charged ions


ions with a negative charge

occur when a cation binds to an anion

ionic bonds

what type of bonding is likely to occur between two water molecules or strands of DNA-

hydrogen bond


multiple forms of an element, differ in the number of neutrons

make up about 95% of the atoms in living organisms

hydrogen, oxygen, carbon, and nitrogen

octet rule

States that atoms lose, gain or share electrons in order to acquire a full set of eight valence electrons in their outer shell

chemical reaction

a change in which one or more reactants change into one or more products; characterized by the breaking of bonds in reactants and the formation of bonds in products

chemical properties

a property or characteristic of a substance that is observed during a reaction in which the chemical composition or identity of the substance is changed

properties of water

1-Universal Solvent (Dissolves all hydrophillic molecules)
2-Cohesion (sticks to itself)
3-Adhesion (sticks to other substances)
4-Heat capacity (water can absorb a lot of heat and remove heat when evaporating due to breaking H-bonds)
5-Surface tension (Water striders can float on water surface)

cell theory

idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells

response to environmental changes

to survive living organisms must be able to respond to changes


Random errors in gene replication that lead to a change in the sequence of nucleotides; the source of all genetic diversity

natural selection

the principle that, among the range of inherited trait variations, those that lead to increased reproduction and survival will most likely be passed on to succeeding generations


Produce and emit light by means of a chemical reaction in which chemical energy is converted to light energy


reducing complex systems to simpler components that are more manageable to study

molecular biology

study of the molecular basis of genes and gene expression; molecular genetics

anatomy and physiology

structures and functions of plants and animals

control group

in an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment

experimental group

A subject or group of subjects in an experiment that is exposed to the factor or condition being tested.


a pure substance made of only one kind of atom

atomic nucleus

An atom's central core, containing protons and neutrons.

energy shells

An energy level representing the distance of an electron from the nucleus of an atom.


the ability to do work or cause change

valence electrons

an electron that is found in the outermost shell of an atom and that determines the atom's chemical properties


what atomic mass is measured in, also known as amu


the amount of a substance that contains as many particles as there are atoms in exactly 12 g of carbon-12

avogadro's number

6.022 x 10^23. The number of particles in exactly one mole of a pure substance


unstable isotope; lose energy by emitting subatomic particles and/or radiation

trace elements

present in extremely small quantities but still are essential for normal growth and function

molecular formula

shows the types and numbers of atoms combined in a single molecule of a molecular compound


refers to a molecule composed of two or more different elements
example: h20

double bond

when atoms share two pairs of electrons


measure of its ability to attract electrons in a bond with another atom

polar molecules

molecules composed predominantly of nonpolar bonds


molecules found in all cells that facilitate or catalyze many biologically important chemical reactions

van der waals forces

a slight attraction that develops between the oppositely charged regions of nearby molecules

if an atom or molecules gains or loses one or more electrons, it acquires a net electric charge and becomes-


free radical

atoms or molecules with one or more unpaired valence electrons


the elements or compounds that enter into a chemical reaction


the elements or compounds produced by a chemical reaction

chemical equilibrium

in a reversible chemical reaction, the point at which the rate of the forward reaction equals the rate of the reverse reaction


substances dissolved in liquid


the liquid in which solutes are dissolved

the solvent for chemical reactions



solvents dissolve in a solvent to form a

aqueous solutions

solutions in which water is the solvent


water loving, polar, dissolve in water, form hydrogen bonds


"Water-fearing"; pertaining to nonpolar molecules (or parts of molecules) that do not dissolve in water


molecule that has both a hydrophilic region and a hydrophobic region such as a phosopholipid


formed when amphipathic molecules are mixed with water, polar regions on outside, non polar regions on inside


a measure of the amount of solute dissolved in a solvent

molecular mass

The sum of the masses of all the atoms in a molecule


A common measure of solute concentration, referring to the number of moles of solute per liter of solution.

What are the three states of water-

1. solid (ice)
2. liquid (water)
3. gas (water vapor)

heat of vaporization

the quantity of heat a liquid must absorb for 1 gram/mole of it to be converted from the liquid to the gaseous state; this is caused by hydrogen bonds

heat of fusion

the amount of heat energy that must be withdrawn or released from a substance to cause it to change from the liquid to the solid state

colligative properties

properties that depend strictly on the total number of dissolved solutes, not on the specific type of solute


Breaking down complex molecules by the chemical addition of water

condensation reaction

Two or more molecules combining to form one larger molecule with the loss of a small molecule

dehydration reaction

a molecule of water is lost during the reaction; a specific kind of condensation reaction


water vaporizes at extraordinary temperatures; it still requires the same energy to change water from a liquid to a gas

specific heat

the amount of heat required to raise the temperature of 1g of a substance 1 degree Celsius (it takes considerable heat to raise the temperature of water)


water molecules attracting to each other; due to hydrogen bonding


the ability of water to be attracted to/adhere to, a surface that is not electrically neutral

surface tension

measure of the attraction between molecules at the surface of a liquid (allows insects to walk on water)

hydroxide ions

Negatively charged particles (OH) composed of oxygen and hydrogen atoms released from a base when dissolved in water


substances that release hydrogen ions when dissolved in water

strong acid

An acid that ionizes completely in aqueous solution
ex:hydrochloric acid

weak acid

an acid that does not completely ionize in water
ex: carbonic acid


compound that absorbs hydrogen ions in a solution
ex: sodium hydroxide; NaOH---> Na+ + OH-


the negative logarithm to the base 10 of the H+ concentration

neutral in pH because the concentration of hydroxide ions and hydrogen ions are equal

pure water

The pH of a solution can affect...

1. The shapes and functions of molecules
2. The rates of many chemical reactions
3. The ability of two molecules to bind to each other
4. The ability of ions or molecules to dissolve in water


composed of a weak acid and its related baseorg;a compound that accepts or releases H+ in response to pH change; help to keep a constant pH

As acidity increases the pH...



pH 0-6
human stomach fluid- pH1
lemon juice-pH2
grapefruit juice-pH3
tomato juice-pH4
urine-pH5 & 6


pH 7
milk, pure water, human blood


pH 8-14
seawater-pH 8
baking soda-pH 9
milk of magnesia-pH 10
household ammonia-pH 11
bleach-pH 12-14

what is the OH- concentration at pH 8?


organic molecules

Contain carbon-hydrogen bonds. Found in living things carbohydrates, lipids, proteins, nucleic acids

organic chemistry

the study of carbon-containing molecules

Carbon forms _____ covalent bonds with other atoms.

4; because Carbon has 4 electrons in its outer shell and needs 4 more


An organic molecule consisting only of carbon and hydrogen; poorly soluble in water

functional groups

groups of atoms with characteristic chemical features and properties


Two structures with an identical molecular formula but different structures and characteristics

structural isomers

contain the same atoms but in different bonding relationships


Identical bonding relationships but the spatial positioning of the atoms differs in the two isomers

cis-trans isomers

Carbons have covalent bonds to the same atoms, but these atoms differ in their spatial arrangements due to the inflexibility of double bonds


pair of molecules that are mirror images

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