Term
|
Definition
| smallest unit with the capacity to live and reproduce |
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Term
|
Definition
| characteristics that depend on the level of organization of matter, but do not exist at lower levels of organization |
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Term
|
Definition
| individual consisting of a single cell |
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Term
|
Definition
| individual consisting of interdependent cells |
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Term
|
Definition
| all the individuals of a single species that live together in the same place and time |
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Term
|
Definition
| all regions of Earth's crust, waters, and atmosphere that sustain life |
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Term
| deoxyribonucleic acid (DNA) |
|
Definition
| the large, double-stranded, helical molecule that contains the genetic material of all living organisms |
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Term
|
Definition
| a polymer assembled from repeating nucleotide monomers in which the five-carbon sugar is ribose. Cellular RNAs include mRNA (which is translated to produce a polypeptide), tRNA (which brings an amino acid to the ribosome for assembly into a polypeptide), and rRNA (which is a structural component of ribosomes). The genetic material of some viruses is RNA. |
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Term
|
Definition
| molecules that carry out most of the activities of life, including the synthesis of all other biological molecules. A protein consists of one or more polypeptides depending on the protein |
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Term
|
Definition
| populations of all species that occupy the same area |
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Term
|
Definition
| group of biological communities interacting with their shared physical environment |
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Term
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Definition
| the biochemical reactions that allow a cell or organism to extract energy from its surroundings and use that energy to maintain itself, grow, and reproduce |
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Term
|
Definition
| the converstion of light energy to chemical energy in the form of sugar and other organic molecules |
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Term
|
Definition
| the process by which energy-rich molecules are broken down to produce energy in the form of ATP |
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Term
|
Definition
| an autotroph, usually a photosynthetic organism, a member of the first trophic level |
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Term
|
Definition
| an organis that consumes other organisms in a community or ecosystem |
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Term
|
Definition
| a small organism, such as a bacterium or fungus, that feeds on the remains of dead organisms, breaking down complex biological molecules or structures into simpler raw materials |
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Term
|
Definition
| a steady internal condition maintained by responses that compensate for changes in the external environment |
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Term
|
Definition
| the process in which parents produce offspring |
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Term
|
Definition
| the transmission of DNA (that is, genetic information) from one generation to the next |
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Term
|
Definition
| a series of programmed changes encoded in DNA, through which a fertilized egg divides into many cells that ultimately are transformed into an adult, which is itself capable of reproduction |
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Term
|
Definition
| the sequential stages through which individuals develop, grow, maintain themselves, and reproduce |
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Term
|
Definition
| the process by which some individuals in a population experience changes in their DNA and pass those modified instructions to their offspring |
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Term
|
Definition
| selective breeding of organisms to ensure that certain desirable traits appear at higher frequency in successive generations |
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Term
|
Definition
| the evolutionary process by which alleles that increase the likelihood of survival and the reproductive output of the individuals that carry them become more common in subsequent generations |
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Term
|
Definition
| a unit containing the code for a protein molecule or one of its parts, or for functioning RNA molecules such as tRNA and rRNA |
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Term
|
Definition
| a spontaneous and heritable change in DNA |
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Term
|
Definition
| characteristic that helps an organism survive longer or reproduce more under a particular set of environmental conditions |
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Term
|
Definition
| a Linnaean taxonomic category ranking below a family and above a species |
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Term
|
Definition
| a group of populations in which the individuals are so closely related in structure, biochemistry, and behavior that they can successfully interbreed |
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Term
|
Definition
| a two-part name identifying the genus to which a species belongs and designating a particular species within that genus |
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Term
|
Definition
| a Linnean taxonomic category that ranks below an order and above a genus |
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Term
|
Definition
| a Linnean taxonomic category of organisms that ranks above a family and below a class |
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Term
|
Definition
| a Linnaean taxonomic category that ranks below phylum and above order |
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Term
|
Definition
| a major Linnean division of a kingdom, ranking above a class |
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Term
|
Definition
| a Linnean taxonomic category that ranks below a domain and above a phylum |
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Term
|
Definition
| in systematics, the highest taxonomic category; a group of cellular organisms with characteristics that set it apart as a major branch of the evolutionary tree |
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Term
|
Definition
| a branching diagram depicting the evolutionary relationships of groups of organisms |
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Term
|
Definition
| organism in which the DNA is suspended in the cell interior without separation from other cellular components by a discrete membrane |
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Term
|
Definition
| organism in which the DNA is enclosed in a nucleus |
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Term
|
Definition
| the nucleus and other specialized internal structures and compartments of eukaryotic cells |
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Term
|
Definition
| the collective effort of individuals who have worked to understand how living systems function |
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Term
|
Definition
| research conducted to search for explanations about natural phenomena in order to satisfy curiosity and to advance collective knowledge of living systems |
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Term
|
Definition
| research conducted with the goal of solving specific practical problems |
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Term
|
Definition
| an investigative approach in which scientists make observations about the natural world, develop working explanations about what they observe, and then test those explanations by collecting more information |
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Term
|
Definition
| basic information on biological structures or the details of biological processes |
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Term
|
Definition
| information that describes the result of a careful manipulation of the system under study |
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Term
|
Definition
| a tentative explanation for an observation, phenomenon, or scientific problem that can be tested by further investigation |
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Term
|
Definition
| a statement of what would be seen if the hypothesis being tested were wrong |
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Term
|
Definition
| an environmental factor that may difer among places or an organismal characteristic that may differ among individuals |
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Term
|
Definition
| a statement about what the researcher expects to happen to one variable if another variable changes |
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Term
|
Definition
| an explanation of an observed phenomenon that is different from the explanation being tested |
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Term
|
Definition
| treatment that tells what would be seen in the absence of the experimental manipulation |
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Term
|
Definition
| the variable in a scientific study that is manipulated by the experimenter |
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Term
|
Definition
| multiple subjects that receive either the same experimental treatment or the same control treatment |
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Term
|
Definition
| an organism with characteristics that make it a particularly useful subject of research because it is likely to produce results widely applicable to other organisms |
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Term
|
Definition
| the manpulation of living organisms to produce useful products |
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Term
|
Definition
| a broadly applicable idea or hypothesis that has been confirmed by every conceivable test |
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Term
|
Definition
| applications of chemical and biological knowledge to decontaminate polluted environments |
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Term
|
Definition
| a pure substance that cannot be broken down into simpler substances by ordinary chemical or physical techniques |
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Term
|
Definition
| anything that occupies space and has mass |
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Term
|
Definition
| an element that occurs in organisms in very small quantities (<0.01%) |
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Term
|
Definition
| the smallest unit that retains the chemical and physical properties of an element |
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Term
|
Definition
| a unit composed of atoms combined chemically in fixed numbers and ratios |
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Term
|
Definition
| the name of a molecule written in chemical shorthand |
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Term
|
Definition
| a molecule whose component atoms are different |
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Term
|
Definition
| the nucleus of an atom, containing protons and neutrons |
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Term
|
Definition
| negatively charged particle outside the nucleus of an atom |
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Term
|
Definition
| positively charged particle in the nucleus of an atom |
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Term
|
Definition
| the number of protons in the nucleus of an atom |
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|
Term
|
Definition
| uncharged particle in the nucleus of an atom |
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Term
|
Definition
| a distinct form of the atoms of an element, with the same number of protons but different number of neutrons |
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|
Term
|
Definition
| a standard unit of mass, about 1.66 x 10 ^-24 grams |
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Term
|
Definition
| the total number of protons and neutrons in the atomic nucleus |
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Term
|
Definition
| the amount of matter in an object |
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Term
|
Definition
| a measure of the pull of gravity on an object |
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Term
|
Definition
| the giving off of particles of matter and energy by decaying nuclei |
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Term
|
Definition
| an unstable, radioactive isotope |
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Term
|
Definition
| isotope used to label molecules so that they can be tracked as they pass through biochemical reactions |
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Term
|
Definition
| the region of space where the elctron "lives" most of the time |
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Term
|
Definition
| regions of space within an atom where electrons are found |
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Term
|
Definition
| an electron in the outermost energy level of an atom |
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Term
|
Definition
| link formed when atoms of reactive elements combine into molecules |
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Term
|
Definition
| bond that results from electrical attractions between atoms that have lost or gained electrons |
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Term
|
Definition
| a positively or negatively charged atom |
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Term
|
Definition
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|
Term
|
Definition
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Term
|
Definition
| bond formed by electron sharing between atoms |
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Term
|
Definition
| the measure of an atom's attraction for the electrons it shares in a chemical bond with another atom |
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Term
|
Definition
| a bond in which electrons are shared equally |
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Term
|
Definition
| bond in which electrons are shared unequally |
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Term
|
Definition
| association that occurs when polar molecules attract and align themselves with other polar molecules and with charged ions and molecules |
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Term
|
Definition
| association that occurs when nonpolar molecules clump together |
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Term
|
Definition
| in chemistry and biology, referring to polar molecules that associate readily with water |
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Term
|
Definition
| in chemistry and biology, referring to nonpolar substances that are excluded by water and other polar molecules |
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Term
|
Definition
| noncovalent bond formed by unequal electron sharing between hydrogen atoms and oxygen, nitrogen, or sulfur atoms |
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Term
|
Definition
| weak molecular attractions over short distances |
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Term
|
Definition
| the atoms or molecules entering a chemical reaction |
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Term
|
Definition
| an atom or molecule leaving a chemical reaction |
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Term
|
Definition
| a chemical reaction written in balanced form |
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Term
|
Definition
| an arrangement formed when a water molecule in liquid water establishes an average of 3.4 hydrogen bonds with its neighbors |
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Term
|
Definition
| a rigid, crystalline structure formed when a water molecule in ice forms four hydrogen bonds with neighboring molecules |
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Term
|
Definition
| the amount of heat required to increase the temperature of a given quantity of water |
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|
Term
|
Definition
| the amount of heat required to raise 1g of water by 1 degree C, known as a "small" calorie |
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|
Term
|
Definition
| a unit equal to 1,000 small calories |
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|
Term
|
Definition
| the scientific unit equivalent to a Calorie and equal to 1,000 small calories |
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|
Term
|
Definition
| the heat required to give water molecules enough energy of motion to break loose from liquid water and form a gas |
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Term
|
Definition
| the high resistance of water molecules to separation |
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Term
|
Definition
| the adherence of molecules to the walls of conducting tubes, as in plants |
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Term
|
Definition
| the force that places surface water molecules under tension, making them more resistant to separation than the underlying water molecules |
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Term
|
Definition
| a membrane with two molecular layers |
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|
Term
|
Definition
| a surface coat of water molecules that covers other polar and charged molecules and ions |
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|
Term
|
Definition
| substance formed when molecules and ions separate and are suspended individually, surrounded by water molecules |
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Term
|
Definition
| the water in a solution in which the hydration layer prevents polar molecules or ions from reassociating |
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Term
|
Definition
| the molecules of a substance dissolved in water |
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Term
|
Definition
| the number of molecules or ions of a substance in a unit volume of space |
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|
Term
|
Definition
| the weight of an element in grams, equal to the mass number |
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|
Term
|
Definition
| the number 6.022 x 10 ^23, derived by dividing the atomic weight of any element by the weight of an atom of that element |
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|
Term
|
Definition
| the weight of a molecule in grams, equal to the total mass number of its atoms |
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Term
|
Definition
| amount of substance that contains as many atoms or molecules as there are atoms in exactly 12 g of carbon- 12, which is 6.022 x 10 ^23 |
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Term
|
Definition
| the number of moles of a substance dissolved in 1 L of solution (moles per liter) |
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Term
|
Definition
| the separation of water to produce hydrogen ions and hydroxide ions |
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Term
|
Definition
| the term indicating that a reaction may go from left to right or from right to left, depending on conditions |
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Term
|
Definition
| proton donor that releases H+ (and anions) when dissolved in water |
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Term
|
Definition
| proton acceptor that reduces the H+ concentration of a solution |
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Term
|
Definition
| the numerical scale used by scientists to measure acidity |
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Term
|
Definition
| substanes that compensate for pH changes by absorbing or relasing H+ |
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Term
|
Definition
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|
Term
|
Definition
| molecule without carbon atoms in its structure |
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Term
|
Definition
| the atoms in reactive groups |
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Term
|
Definition
| group consisting of an oxygen atom linked to a hydrogen atom on one side and to a carbon chain on the other side |
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|
Term
|
Definition
| a molecule of the form R--OH in which R is a chain of one or more carbon atoms, each of which is linked to hydrogen atoms |
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Term
|
Definition
| the reactive part of aldehydes and ketones, consisting of an oxygen atom linked to a carbon atom by a double bond |
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Term
|
Definition
| molecule in which the carbonyl group is linked to a carbon atom at the end of a carbon chain, along with a hydrogen atom |
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Term
|
Definition
| molecule in which the carbonyl group is linked to a carbon atom in the interior of a carbon chain |
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Term
|
Definition
| the characgteristic functional group of organic acids, formed by the combination of carbonyl and hydroxyl groups |
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Term
|
Definition
| carboxylic acid; acid for which the characteristic functional group is a carboxyl group (-COOH) |
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|
Term
|
Definition
| group that acts as an organic base, consisting of a nitrogen atom bonded on one side to two hydrogen atoms and on the other side to a carbon chain |
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Term
|
Definition
| group consisting of a central phosphorous atom held in four linkages: two that bind -OH groups to the central phosphorous atom, a third that binds an oxygen atom to the central phosphorous atom, and a fourth that links the phosphate group to an oxygen atom |
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Term
|
Definition
| group that works as a molecular fastener, consisting of a sulfur atom linked on one side to a hydrogen atom and on the other side to a carbon chain |
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Term
|
Definition
| linkage that occurs when two sulfhydryl groups interact during a linking reaction |
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Term
|
Definition
| two or more molecules with the same chemical formula but different molecular structures |
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|
Term
| enantiomers (optical isomers) |
|
Definition
| isomers that are mirror images of each other |
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Term
|
Definition
| two molecules with the same chemical formula but atoms that are arranged in different ways |
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|
Term
| dehydration synthesis reaction / condensation reaction |
|
Definition
| reaction during which the components of a water molecule are removed, usually as part of the assembly of a larger molecules from smaller subunits |
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Term
|
Definition
| reaction in which the components of a water molecule are added to function groups as molecules are broken into smaller subunits |
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Term
|
Definition
| energy-providing carbohydrates stored in animal cells |
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Term
|
Definition
| a storage polysaccharide in plants consisting of branched or unbranched chains of glucose subunits |
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Term
|
Definition
| one of the primary constituents of plant cell walls, formed by chains of carbohydrate subunits |
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Term
|
Definition
| the smallest carbohydrates, containing three to seven carbon atoms |
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Term
|
Definition
| chain with more than 10 linked monosaccharide subunits |
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Term
|
Definition
| bond formed by the linkage of two alpha-glucose molecules with oxygen as bridge between a carbon of the first glucose and a carbon of the second glucose unit |
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Term
|
Definition
| energy-storing molecule consisting of a glycerol backbone and three fatty acid chains |
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Term
|
Definition
| neutral lipid that is liquid at biological temperatures |
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Term
|
Definition
| neutral lipid that is semisolid at biological temperatures |
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Term
|
Definition
| one of two components of a neutral lipid, containing a single hydrocarbon chain with a carboxyl group linked at one end |
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Term
|
Definition
| fatty acid with only single bonds linking the carbon atoms |
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|
Term
|
Definition
| fatty acid with one or more double bonds linking the carbons |
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|
Term
|
Definition
| fatty acids with one double bond |
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|
Term
|
Definition
| fatty acid with more than one double bond |
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Term
|
Definition
| a nonpolar compound produced when a fatty acid binds by a dehydration synthesis reaction at each of glycerol's three --OH bearing sites |
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Term
|
Definition
| a substance insoluble in water that is formed when fatty acids combine with long-chain alcohols or hydrocarbon structures |
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Term
|
Definition
| a phosophate-containing lipid |
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Term
|
Definition
| a type of lipid derived from cholesterol |
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Term
|
Definition
| steroid with a single polar --OH group linked to one end of the ring framework and a complex, nonpolar hydrocarbon chain at the other end |
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Term
|
Definition
| the predominant sterol of animal cell membranes |
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Term
|
Definition
| a sterol that occurs in plant cell membranes |
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Term
|
Definition
| protein that accelerates the rate of a cellular reaction |
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Term
|
Definition
| a molecule that contains both an amino and a carboxyl group |
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Term
|
Definition
| a link formed by a dehyrdation synthesis reaction between the --NH3 group of one amino acid and the --COOH group of a second |
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Term
|
Definition
| the end of a polypeptide chain with an --NH3+ group |
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|
Term
|
Definition
| the end of an amino acid chain with a -COO- group |
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|
Term
|
Definition
| the chain of amino acids formed by sequential peptide bonds |
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|
Term
|
Definition
| the sequence of amino acids in a protein |
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|
Term
|
Definition
| regions of alpha helix, beta strand, or random coil in a polypeptide chain |
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Term
|
Definition
| the overall three dimensional folding of a polypeptide chain (globular) |
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|
Term
|
Definition
| the arrangement of polypeptide chains in a protein that contains more than one chain |
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|
Term
|
Definition
| a type of secondary structure of a polypeptide in which the amino acid chain is twisted into a regular, right-hand spiral |
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|
Term
| beta sheet (pleated sheet) |
|
Definition
| a type of secondary structure in a polypeptide in which the amino acid chain zigzags in a flat plane to form a beta strand, and beta strands then align side by side in the same or opposite direction |
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|
Term
|
Definition
| an arrangement of the amino acid chain providing flexible regions that allow sections of the chain to bend |
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|
Term
|
Definition
| the overall 3D shape of a protein |
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|
Term
|
Definition
| a loss of both the structure and function of a protein due to extreme conditions that unfold it from its normal conformation |
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|
Term
|
Definition
| the reformation of a denatured protein into its folded, functional state |
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|
Term
| chaperone proteins (chaperonins) |
|
Definition
| "guide" protein that binds temporarily with newly synthesized proteins, directing their conformation toward the correc tertiary structure and inhibiting incorrect arrangements as the new proteins fold |
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|
Term
|
Definition
| alteration in the 3D shape of a protein |
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Term
|
Definition
| in protein structure a distinct, large, structural subdivision produced in many proteins by the folding of the amino acid chain |
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Term
|
Definition
| a highly specialized region in a protein produced by the 3D arrangement of amino acid chains within and between domains |
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Term
|
Definition
| the monomer of nucleic acids consisting of a 5 carbon sugar, a nitrogenous base, and a phosphate |
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Term
|
Definition
| a nitrogen-containing molecule with the properties of a base |
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|
Term
|
Definition
| a type of nitrogenous base with one carbon-nitrogen ring |
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|
Term
|
Definition
| a type of nitrogenous base with two carbon-nitrogen rings |
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|
Term
|
Definition
| a 5-carbon sugar to which a nitrogenous base and a phosphate group link covalently in a nucleotide of DNA |
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|
Term
|
Definition
| a five carbon sugar to which the nitrogenous bases in nucleotides link covalently |
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|
Term
|
Definition
| nucelotide containing deoxyribose as the sugar; components of DNA |
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|
Term
|
Definition
| nucleotide containing ribose as the sugar; ribonucleotides are components of RNA |
|
|
Term
|
Definition
| chemical structure containing only a nitrogenous base and a five carbon sugar |
|
|
Term
|
Definition
| the linkage of nucleotides in polynucleotide chains by a bridging phosphate group between the 5' carbon of one sugar and the 3' carbon of the next sugar in line |
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|
Term
|
Definition
| two nucleotide chains wrapped around each other in a spiral |
|
|
Term
|
Definition
| a nucleotide chain used in DNA replication for the assembly of a complementary chain |
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Term
|
Definition
| three generalizations yielded by microscopic observations: all organisms are composed of one or more cells; the cell is the smallest unit that has the properties of life; and cells arise only from the growth and division of preexisting cells |
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Term
|
Definition
| technique for producing visible images of objects that are too small to be seen by the human eye |
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Term
|
Definition
| instrument of microscopy with different magnifications and resolutions of specimens |
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Term
|
Definition
| microscope that uses light to illuminate the specimen |
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|
Term
|
Definition
| microscope that uses electrons to illuminate the specimen |
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Term
|
Definition
| the ratio of an object as viewed to its real size |
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|
Term
|
Definition
| the minimum distance two points in a specimen can be separated and still be seen as two points |
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Term
|
Definition
| the outer limit of the cytoplasm responsible for the regulation of substances moving into and out of the cells |
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Term
|
Definition
| all the parts of the cell that surround the central nucelus (eukaryotes) or nucleoid region (prokaryotes) |
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|
Term
|
Definition
| the nucleus and other specialized internal structures and copartments of eukaryotic cells |
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|
Term
|
Definition
| aqueous solution in the cytoplasm containing ions and various organic molecules |
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|
Term
|
Definition
| the interconnected system of protein fibers and tubes that extends throughout the cytoplasm of a eukaryotic cell |
|
|
Term
|
Definition
| the central region of a prokaryotic cell with no boundary membrane separating it from the cytoplasm, where DNA replication and RNA transcription occur |
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|
Term
|
Definition
| the central region of eukaryotic cells, separated by membranes from the surrounding cytoplasm, where DNA replication and messenger RNA transcription ocur |
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|
Term
|
Definition
| a single, typically circular DNA molecule |
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|
Term
|
Definition
| a ribonuceloprotein particle that carries out protein synthesis by translating mRNA into chains of amino acids |
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Term
|
Definition
| a rigid external layer of material surrounding the plasma membrane of cells in plants, fungi, bacteria, and some protists, providing cell protection and support |
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Term
|
Definition
| a carbohydrate coat covering the cell surface |
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|
Term
|
Definition
| a coat typically composed of polysaccahrides that is loosely associated with bacterial cells |
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|
Term
|
Definition
| an external layer of sticky or slimy polysaccharides coating the cell wall in many prokaryotes |
|
|
Term
|
Definition
| a long, threadlike, cellular appendage responsible for movement; found in both prokaryotes and eukaryotes, but with different structures and modes of locomotion |
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Term
|
Definition
| in eukaryotes, membranes separating the nucleus from the cytoplasm |
|
|
Term
|
Definition
| a large, octagonally symmetrical, clindrical structure that functions to exchange molecules between the nucleus and cytoplasm and prevents the transport of material not meant to cross the nuclear membrane. A nuclear pore -- a channel through the complex -- is the path for the exchange of molecules |
|
|
Term
| nuclear localization signal |
|
Definition
| a short amino acid sequence in a protein that directs the protein to the nucleus |
|
|
Term
|
Definition
| the liquid or semiliquid substance within the nucleus |
|
|
Term
|
Definition
| any assemblage of eukaryotic nuclear DNA molecules and their associated proteins |
|
|
Term
|
Definition
| a DNA molecule, with its associated proteins, in the nucleus of a eukaryotic cell |
|
|
Term
|
Definition
| the nuclear site of rRNA transcription, processing, and ribosome assembly in eukaryotes |
|
|
Term
|
Definition
| in eukaryotes, a collection of interrelated internal membranous sacs that divide a cell into functional and structural compartments |
|
|
Term
|
Definition
| a small, membrane-bound compartment that transfers substances between parts of the endomembrane system |
|
|
Term
| endoplasmic reticulum (ER) |
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Definition
| in eukaryotes, an extensive interconnected network of cisternae that is responsible for the synthesis, transport, and initial modification of proteins and lipids |
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Definition
| membranous channels and vesicles that make up the endoplasmic reticulum |
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Definition
| the enclosed space surrounded by the cisterna |
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Definition
| endoplasmic reticulum with many ribosomes studding its outer surface |
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Definition
| endoplasmic reticulum with no ribosomes attached to its membrane surfaces; has various functions, including synthesis of lipids that become part of cell membranes |
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Definition
| in eukaryotes, the organelle responsible for the final modification, sorting, and distribution of proteins and lipids |
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Definition
| vesicles that transport proteins to the plasma membrane |
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Definition
| in eukaryotes, the process by which a secretory vesicle fuses with the plasma membrane and releases the vesicle contents to the exterior |
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Definition
| vesicle that acarries proteins and other molecules from the plasma membrane to destinations within the cell |
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Definition
| membrane-bound vesicle containg hydrolytic enzymes for the digestion of many complex molecules |
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Definition
| process in which some types of cells engulf bacteria or other cellular debris to break them down |
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Definition
| membrane-bound organelles responsible for synthesis of most of the ATP in eukaryotic cells |
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Term
| outer mitochondrial membrane |
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Definition
| the smooth membrane covering the outside of a mitochondrion |
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Term
| inner mitochondrial membrane |
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Definition
| membrane surrounding the mitochondrial matrix |
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Definition
| fold that expands the surface area of the inner mitchondrial membrane |
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Definition
| the innermost compartment of mitochondrion |
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Definition
| small, membrane-bound organelle that caries out vital reactions linking metabolic bathways |
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Definition
| microbody that produces hydrogen peroxide as a by product |
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Definition
| a cytoskeletal component formed by the polymerization of tubulin into rigid, hollow rods about 25 nm in diameter |
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Definition
| the main microtubule organizing center of a cell, which organizes the microtubule cytoskeleton during interphase and positions many of the cytoplasmic organelles |
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Definition
| a cylindrical structure consisting of nine triplets of microtubules in the centrosomes of most animal cells |
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Definition
| a cytoskeletal filament about 10 nm in diameter that provides mechanical strength to cells in tissues |
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Definition
| a cytoskeletal filament composed of actin |
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Definition
| structure that anchors cilia and flagella to the surface of a cell |
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Definition
| the site of photosynthesis in plant cells |
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Definition
| a family of plant organelles that includes chloroplasts, amyloplasts, and chromoplasts |
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Definition
| colorless plastid that stores starch in plants |
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Definition
| plastid containing red and yellow pigments |
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Definition
| a smooth membrane that surrounds a chloroplast, enclosing the stroma |
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Definition
| membrane lying just inside the outer boundary membrane of a chloroplast, enclosing the stroma |
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Definition
| structure in the chloroplasts of higher plants formed by thylakoids stacked one on top of another |
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Definition
| a large, water-filled organelle in plant cells that maintains the turgor of the cell and controls movement of molecules between the cytosol and sap |
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Definition
| the membrane that surround the central vacuole in a plant cell |
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Definition
| the initial cell wall laid down by a plant cell |
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Definition
| a layer added to the cell wall of plants that is more rigid and may become many times thicker than the primary cell wall |
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Term
| plasmodesma (pl. plasmodesmata) |
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Definition
| a minute channel that perforates a cell wall and contains extensions of the cytoplasm that directly connect adjacent plant cells |
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Term
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Definition
| a cell surface protein responsible for selectively binding cells together |
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Term
| extracellular matrix (ECM) |
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Definition
| a molecular system that supports and protects cells and provides mechanical linkages |
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Definition
| cell junction that forms belts that run entirely around cells, "welding" adjacent cells together |
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Definition
| anchoring junction for which microfilaments anchor the junction in the underlying cytoplasm |
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Definition
| animal cell junctions in which intermediate filaments are the anchoring cytoskeletal component |
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Definition
| region of tight connection between membranes of adjacent cells |
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Definition
| junction that opens direct channels allowing ions and small molecules to pass directly from one cell to another |
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Definition
| the outer limit of the cytoplasm responsible for the regulation of substances moving into and out of cells |
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Definition
| the predominant sterol of animal cell membranes |
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Definition
| a protein embedded in the cell membrane that forms a channel allowing selected polar molecules and ions to pass across the membrane |
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Definition
| protein in the plasma membrane that identifies a cell as part of the same individual or as foreign |
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Definition
| protein that recognizes and binds molecules from other cells that act as chemical signals |
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Definition
| protein that binds cells together by recognizing and binding receptors or chemical groups on other cells or on the extracellular matrix |
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Definition
| a lipid molecule with carbohydrate groups attached |
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Definition
| a protein with carbohydrate groups attached |
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Definition
| model proposing that the membrane consists of a fluid phospholipid bilayer in which proteins are embedded and float freely |
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Definition
| protein embedded in a phospholipid bilayer |
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Term
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Definition
| proteins held to membrane surfaces by noncovalent bonds formed with the polar parts of integral membrane proteins or membrane lipids |
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Term
| freeze-fracture technique |
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Definition
| technique in which experimenters freeze a block of cells rapidly, then fracture the block to split the lipid bilayer and expose the hydrophobic membrane interior |
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Term
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Definition
| the controlled movement of ions and molecules from one side of a membrane to the other |
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Term
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Definition
| the transport of substances across cell membranes without expenditure of energy, as in diffusion |
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Term
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Definition
| the mechanism by which ions and molecules move against the concentration gradient across a membrane, from the side with the lower concentration to the side with the higher concentration |
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Term
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Definition
| the net movement of ions or molecules from a region of higher concentration to a region of lower concentration |
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Definition
| the concentration difference that drives diffusion |
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Term
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Definition
| membranes that selectively allow, impede, or block the passage of atoms and molecules |
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Term
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Definition
| mechanism by which certain small substances diffuse through the lipid part of a biological membrane |
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Term
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Definition
| mechanism by which polar and charged molecules diffuse across membranes with the help of transport proteins |
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Term
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Definition
| transport protein that forms a hydrophilic channel in a cell membrane through which water, ions, or other molecules can pass, depending on the protein |
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Term
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Definition
| a specialized protein channel that facilitates diffusion of water through cell membranes |
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Term
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Definition
| ion transporter in a membrane that switches between open, closed, or intermediate states |
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Term
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Definition
| transport protein that binds a specific single solute and transports it across the lipid bilayer |
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Term
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Definition
| the passive transport of water across a selectively permeable membrane in response to solute concentration gradients, a pressure gradient, or both |
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Term
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Definition
| a state of dynamic equilibrium in which the pressure of the solution on one side of a selectively permeable membrane exactly balances the tendency of water molecules to diffuse passively from the other side of the membrane due to a concentration gradient |
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Term
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Definition
| solution containing dissolved substances at lower concentrations than the cells it surrounds |
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Term
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Definition
| the internal hydrostatic pressure within plant cells |
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Term
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Definition
| solution containing dissolved substances at higher concentrations than the cells it surrounds |
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Term
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Definition
| condition due to outward osmotic movement of water, in which plant cells shrink so much that they retract from their walls |
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Term
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Definition
| equal concentration of water inside and outside cells |
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Term
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Definition
| an electrical voltage that measures the potential inside a cell membrane relative to the fluid just outside; it is negative under resting conditions and becomes positive during an action potential |
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Term
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Definition
| transport in which the same protein that transports a substances also hydrolyzes ATP to power the transport directly |
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Term
| secondary active transport |
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Definition
| transport indirectly driven by ATP hydrolysis |
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Term
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Definition
| pump that moves hydrogen ions across membranes and pushes hydrogen ions across the plasma membrane from the cytoplasm to the cell exterior |
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Term
| Ca 2+ pump (calcium pump) |
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Definition
| pump that pushes Ca 2+ from the cytoplasm to the cell exterior, and also from the cytosol into the vesicles of the endoplasmic reticulum |
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Term
| Na+/K+ pump (sodium-potassium pump or Na+/K+-ATPase) |
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Definition
| pump that pushes 3 Na+ out of the cell and 2 K+ into the cell in the same pumping cycle |
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Term
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Definition
| a difference in chemical concentration and electric potential across a membrane |
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Term
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Definition
| the transport of two molecules in the same direction across a membrane |
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Term
| antiport (exchange diffusion) |
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Definition
| a secondary active transport mechanism in which a molecule moves through a membrane channel into a cell and powers the active transport of a second molecule out of the cell |
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Term
| bulk-phase endocytosis (pinocytosis) |
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Definition
| mechanism by which extracellular water is taken into a ell together with any molecules that happen to be in solution in the water |
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Term
| receptor-mediated endocytosis |
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Definition
| the selective uptake of macromolecules that bind to cell surface receptors concentrated in clathrin-coated pits |
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Term
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Definition
| a depression in the plasma memebrane the contains receptors for macromolecules to be taken up by endocytosis |
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Term
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Definition
| the network of proteins that coat and reinforce the cytoplasmic surface of cell membranes |
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Term
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Definition
| process in which some types of cells engulf bacteria or other cellular debris to break them down |
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