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VOCABULARY ONLY!! (it's a lot)


anything that occupies space and has mass


pure substance that cannot be broken down into other substances by chemical or physical means

trace element

element critical to health that makes up less than 0.01 percent of body mass


substance containing two or more elements chemically combined in a fixed ratio


smallest particle of an element


subatomic particle with a single unit of positive electric charge


subatomic particle with a single unit of negative electric charge


subatomic particle that has no charge


in an atom, the central core that contains protons and neutrons (Concept 4.2); in a cell, the part that houses the cell's genetic material in the form of DNA

atomic number

number of protons in an atom's nucleus; is unique for each element


one of several forms of an element, each containing the same number of protons in their atoms but a different number of neutrons

radioactive isotope

isotope in which the nucleus decays (breaks down) over time, giving off radiation in the form of matter and energy

ionic bond

chemical bond that occurs when an atom transfers an electron to another atom


atom that has become electrically charged as a result of gaining or losing an electron

covalent bond

chemical bond that forms when two atoms share electrons


two or more atoms held together by covalent bonds

chemical reaction

breaking of old and formation of new chemical bonds that result in new substances


starting material for a chemical reaction


material created as a result of a chemical reaction

polar molecule

molecule in which opposite ends have opposite electric charges

hydrogen bond

bond created by the weak attraction of a slightly positive hydrogen atom to a slightly negative portion of another molecule


tendency of molecules of the same kind to stick to one another


attraction between unlike molecules

thermal energy

total amount of energy associated with the random movement of atoms and molecules in a sample of matter


measure of the average energy of random motion of particles in a substance


uniform mixture of two or more substances


substance in a solution that dissolves the other substance and is present in the greater amount


substance in a solution that is dissolved and is present in a lesser amount

aqueous solution

solution in which water is the solvent


compound that donates H+ ions to an aqueous solution and measures less than 7 on the pH scale


compound that removes H+ ions from an aqueous solution and that measures more than 7 on the pH scale

pH scale

a range of numbers used to describe how acidic or basic a solution is; ranges from 0 (most acidic) to 14 (most basic)


substance that maintains a fairly constant pH in a solution by accepting H+ ions when their levels rise and donating H+ ions when their levels fall

organic molecule

carbon-based molecule

inorganic molecule

non-carbon-based molecule


organic molecule composed of only carbon and hydrogen atoms

functional group

group of atoms within a molecule that interacts in predictable ways with other molecules


attracts water molecules


small molecular unit that is the building block of a larger molecule


long chain of small molecular units (monomers )


organic compound made of sugar molecules


sugar containing one sugar unit


sugar containing two monosaccharaides


long polymer chain made up of simple sugar monomers


polysaccharide in plant cells that consists entirely of glucose monomers


polysaccharide in animal cells that consists of many glucose monomers


polysaccharide consisting of glucose monomers that reinforces plant-cell walls


one of a class of water-avoiding compounds


avoids water molecules


organic compound consisting of a three-carbon backbone (glycerol) attached to three fatty acids

saturated fat

fat in which all three fatty acid chains contain the maximum possible number of hydrogen atoms

unsaturated fat

fat with less than the maximum number of hydrogens in one or more of its fatty acid chains


lipid molecule with four fused carbon rings


steroid molecule present in the plasma membranes of animal cells


polymer constructed from a set of 20 amino acid monomers

amino acid

monomer that makes up proteins; contains carboxyl and amino functional groups


chain of linked amino acids


loss of normal shape of a protein due to heat or other factor

activation energy

minimum amount of energy required to trigger a chemical reaction


agent that speeds up chemical reactions


specialized protein that catalyzes the chemical reactions of a cell


specific reactant acted on by an enzyme

active site

region of an enzyme into which a particular substrate fits

cell theory

generalization that all living things are composed of cells, and that cells are the basic unit of structure and function in living things


photograph of the view through a microscope


part of a cell with a specific function

plasma membrane

thin outer boundary of a cell that regulates the traffic of chemicals between the cell and its surroundings


in an atom, the central core that contains protons and neutrons (Concept 4.2); in a cell, the part that houses the cell's genetic material in the form of DNA


region of a cell between the nucleus and the plasma membrane

cell wall

strong wall outside a plant cell's plasma membrane that protects the cell and maintains its shape

prokaryotic cell

cell lacking a nucleus and most other organelles

eukaryotic cell

cell with a nucleus (surrounded by its own membrane) and other internal organelles

phospholipid bilayer

two-layer "sandwich" of molecules that surrounds a cell


net movement of the particles of a substance from where they are more concentrated to where they are less concentrated


point at which the number of diffusing molecules moving in one direction is equal to the number moving in the opposite direction

selectively permeable membrane

membrane that allows some substances to pass more easily than others and blocks the passage of some substances altogether

passive transport:

diffusion across a membrane requiring only the random motion of molecules with no energy expended by the cell

facilitated diffusion

pathway provided by transport proteins that helps certain molecules pass through a membrane


passive transport of water across a selectively permeable membrane


having a higher concentration of solute than another solution


having a lower concentration of solute than another solution


having a solute concentration equal to that of another solution

active transport

movement of molecules across a membrane requiring energy to be expended by the cell


small membrane-bound sac that functions in moving products into, out of, and within a cell


process of exporting proteins from a cell by a vesicle fusing with the plasma membrane and spilling the proteins outside the cell


process of taking material into a cell within vesicles that bud inward from the plasma membrane

nuclear envelope

double membrane that surrounds a cell nucleus


ball-like mass of fibers and granules in a cell nucleus


cluster of proteins and nucleic acids that constructs proteins in a cell

endoplasmic reticulum

network of membranes within a cell's cytoplasm that produces a variety of molecules

Golgi apparatus

cellular organelle that modifies, stores, and routes cell products


membrane-bound sac that buds from the endoplasmic reticulum or the Golgi apparatus


`membrane-bound sac containing digestive enzymes that can break down proteins, nucleic acids, and polysaccharides


organelle found in some plant cells and certain unicellular organisms where photosynthesis takes place


cellular organelles where cellular respiration occurs


(adenosine triphosphate) main energy source that cells use for most of their work


straight, hollow tube of proteins that gives rigidity, shape, and organization to a cell


solid rod of protein, thinner than a microtubule, that enables a cell to move or change shape


long, thin, whip-like structures, with a core of microtubules, that enable some cells to move


short structures projecting from a cell and containing bundles of microtubules that move a cell through its surroundings or move fluid over the cell's surface


combination of DNA and protein molecules, in the form of long, thin fibers, making up the genetic material in the nucleus of a eukaryotic cell


condensed threads of genetic material formed from chromatin as a cell prepares to divide

sister chromatid

one of a pair of identical chromosomes created before a cell divides


region where two sister chromatids are joined tightly together

cell cycle

sequence of events from the production of a eukaryotic cell to the time the cell itself reproduces


stage of the cell cycle during which a cell carries out its metabolic processes and performs its functions in the body

mitotic phase

stage of the cell cycle when a cell is actively dividing


process by which the nucleus and duplicated chromosomes of a cell divide and are evenly distributed, forming two daughter nuclei


process by which the cytoplasm of a cell is divided in two; usually follows mitosis and meiosis


framework of microtubules that guide the movement of chromosomes during mitosis and meiosis


region of cytoplasmic material that in animal cells contains structures called centrioles


first stage of mitosis and of meiosis I and II, when the already replicated chromosomes condense


second stage of mitosis and of meiosis I and II when the spindle is fully formed and all of the chromosomes are held in place


third phase of mitosis and of meiosis I and II, in which the sister chromatids separate and move toward the poles of the spindle


final stage of mitosis and of meiosis I and II, in which the chromosomes reach the spindle poles, nuclear envelopes form around each set of daughter chromosomes, and the nucleoli reappear


type of cell division that produces cells with half as many chromosomes as the parent cell


display of a person's 46 chromosomes

homologous chromosome

one of a matching pair of chromosomes, one inherited from each parent


having two homologous sets of chromosomes


having a single set of chromosomes


variation of a particular inherited character


study of heredity


process by which sperm from one flower's pollen fertilizes the eggs in a flower of a different plant


offspring of two different true-breeding varieties

monohybrid cross

mating of two organisms that differ in only one character


alternative form of a gene


having identical alleles for a gene


having different alleles for a gene


descriptive of an allele in a heterozygous individual that appears to be the only one affecting a trait


descriptive of an allele in a heterozygous individual that does not appear to affect a trait

Punnett square

diagram showing the probabilities of the possible outcomes of a genetic cross


observable traits of an organism


genetic makeup of an organism; an organism's combination of alleles


mating of an individual of unknown genotype but dominant phenotype with a homozygous recessive individual

dihybrid cross

mating of two organisms that differ in two characters

intermediate inheritance

inheritance in which heterozygotes have a phenotype intermediate between the phenotypes of the two homozygotes


inheritance pattern in which a heterozygote expresses the distinct traits of both alleles

polygenic inheritance

combined effect of two or more genes on a single character

chromosome theory of inheritance

generalization that genes are located on chromosomes and that the behavior of chromosomes during meiosis and fertilization accounts for inheritance patterns

gene locus

specific location of a gene on a chromosome

genetic linkage

tendency for alleles of genes on the same chromosome to be inherited together

sex-linked gene

gene located on a sex chromosome


package of nucleic acid wrapped in a protein coat that must use a host cell's machinery to reproduce itself


: virus that infects bacteria; also called a "phage"

deoxyribonucleic acid (DNA

molecule responsible for inheritance; nucleic acid that contains the sugar deoxyribose


building block (monomer) of nucleic acid polymers

nitrogenous base

single or double ring of carbon and nitrogen atoms with attached functional groups, found in nucleic acids


single-ring nitrogenous base


double-ring nitrogenous base

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