AP Biology Vocabulary

Be sure to understand the following vocabulary before the exam!


1) Natural Selection: process by which individuals that are better suited to their environment survive and reproduce; survival of the fittest

2) Population: a group of individuals of the same species that live in the same area

3) Population Genetics: the study of populations and genetics overtime

4) Gene Pool: combined genetic information of all members of a particular population

5) Genotype: genetic make-up of an organism

6) Phenotype: physical make-up of an organism

7) Equilibrium: when the genes are the same from one generation to another

8) Mutations: a change in a DNA sequence that affects genetic information; not necessarily bad/good

9) Gene Flow: the process of genes moving from one population to another

10) Genetic Drift: when allele frequencies in a population change because of random events

11) Population Bottleneck: a population is a reduced by an event leaving few mates and genes to pass; a cause of Genetic Drift

12) Founder Effect: change in allele frequencies because of the migration of a small subgroup of a population; a cause of Genetic Drift

13) Stabilizing Selection: individuals with the average form of a trait have the highest fitness; normal distribution

14) Disruptive Selection: individuals with extremes of a trait have the higher fitness compared to the average individuals

15) Directional Selection: individuals that display an extreme form of a trait have a greater fitness than individuals with an average form of a trait 

16) Sexual Selection: choosing a mate based on similar characteristics (usually exhibited by female individuals); produce desired offspring *Polygyny: males compete; females care for the young *Monogamy: males and females both care for the young

17) Adaption: inherited characteristics that increase an organism’s chance of survival

18) Fitness: an organism’s genetic contribution to the next generation; the ability to reproduce

19) Polymorphism: the coexistence within a population of two or more phenotypically distinct forms

20) Cline: a graded change in a characteristic along a geographic axis

21) Species: a group of similar organisms that can breed and produce fertile offspring

22) Cladogenesis: (speciation)one species splits intotwo species, which, thereafter, evolve as distinct lineages

23) Allopatric Speciation: speciation of a population of organisms that develop from geographic separation/barrier

24) Sympatric Speciation: speciation of a population without a geographical barrier

25) Polyploidy: the possession of more than the normal 2 sets of chromosomes found in diploid (2n) cell

26) Prezygotic Barrier/Isolating Mechanism: the prevention of mating between members of different species due to sound, mating seasons, temperature, and pheromones

27) Postzygotic Barrier/Isolating Mechanism: prevents the production of fertile offspring

28) Hybrid: offspring of crosses between parents with different alleles/traits

29) Adaptive (Evolution) Radiation: the rapid evolution of many species from a single ancestor

30) Stasis: inactivity in the process of life

31) Punctuated Equilibrium: evolutionary history consisting of long period of stasis interrupted by periods of rapid change/macroevolution

32) Taxonomy: the classification of organisms; assigning a universally accepted name

33) Binomial Nomenclature: classification system in which each organism is given a universally accepted name

34) Homologous: similarities in a structure/position assumed to result from common ancestry – common evolutionary origin.

35) Divergent Evolution: two or more species that come from a common ancestor

36) Convergent Evolution: two unrelated species that have similar traits (i.e.: emu and ostrich)

37) Analogous: body parts that resemble one another in different species,not because of common ancestry,but because of environmental adaptations

Inorganic Chemistry

38) Atom: the basic unit of matter

39) Proton: a positively charged particle in the nucleus of ana tom 

41) Neutron: a neutrally charged particle located in the nucleus of ana tom; can create isotopes

42) Electron: a negatively charged particle located in the energy levels of ana tom

43) Atomic Number: the number ofprotons in anatom

44) Atomic Weight: the sum of theprotons and theneutrons

45) Isotope: atoms with the same number ofprotons andelectrons but a different number ofneutrons

46) Potential Energy: the energy available to be used for reactions

47) Energy Level(s): each level in anatom

48) Orbital: the lowest energy level possible forelectrons (2)

49) Ion: anatom with a negative or positive charge due to the gain or release of electron(s) *Muscle Contraction: (Ca++) sodium/chloride ions = muscle function & impulses in nervous system *Chlorophyll:(M g+ +)

50) Bond: the attachment ofa toms due to the sharing/transferring ofelectrons

51) Molecule: simplest part of a substance retaining all of the properties of the substance; can exist in a free state

52) Ionic Bonds:bonds formed when one or more electrons are transferred from one atom to another

53) Covalent Bonds: the sharing ofelectron pairs

54) Polar Molecule: charges betweenelectrons andprotons are unbalanced

55) Non-polar Molecule: charges betweenelectrons andprotons are balanced

56) Double Bond: whenatoms share two pairs ofelectrons

57) Biosphere: part of Earth in which life exists including the land, bodies of water, and air/atmosphere

58) Compound: substance formed by the chemical combination of two or more elements in definite properties

59) Quantum: an amount of energy needed to move anelectron from oneorbita l to another

60) Hydrogen Bond: a weak molecularbond linking a hydrogena tom to anotheratom

61) Surface Tension: the result ofcohes ion; the clinging together of watermolecules

62) Cohesion: holding together of the samemolecules

63) Adhesion: holding together of differentmolecules

64) Lattice of H2O:when hydrogen bonds form a lattice like figure due to expansion of watermolecules

65) Capillary Action: causes a liquid to rise up fine tubes; caused bycohes ion and adhesion

66) Imbibition: the movement of water into substances, which, as a result, cause it to swell

67) Specific Heat: amount of heat a given substance requires for a temperature increase

68) Kinetic Energy: the energy used for work; seen in chemical reactions

69) Vaporization: the phase transition from a liquid to a gas

70) Heat of Vaporization (Evaporation): when the phase transition occurs below the boiling point

71) Density: weight of material in a given volume

72) Heat of Fusion: the amount of heat released/required to freeze/melt a substance (79.7 Cal/gram)

73) Solution: uniform mixture of two or more substances

74) Solvent: the substance present in the greatest amount; water is the universal solvent

75) Solute: the substance present in the least amount

76) Hydrophilic: polar molecules have an affinity with water

77) Hydrophobic: non-polar molecules tend to mass together but do not mix with water (i.e.: oil)

78) Equilibrium: when the concentration of thes olutes is the same throughout a solution

79) Acid: as olution with a surplus of hydroxideions; sour tasting;pH of 0-6

80) Base: as olution with a surplus of hydroxylions; also known as “alkali”;pH of 8-14

81) Calorie: the amount ofhea t required to raise thetempera ture of one gram of water, one degree Celsius

82) Ionization: is the physical process of converting an atom or molecule into an ion by adding or removing charged particles such as electrons or other ions

Organic Chemistry 

83) Carbohydrate: molecule composed of sugars

84) Lipid: (fats) non-polar molecules containing fatty acids

85) Protein: (enzymes) composed of amino acids (20)

86) Nucleotide: complex molecule with roles in energy and nucleic acids found in DNA< RNA, and ATP

87) Organic Molecule: molecules containing carbon

88) Hydrocarbon: an organic compound consisting only carbon and hydrogen

89) Functional Group: a specific configuration of atoms commonly attached to the carbon skeletons of organic molecules; chemical reactions

90) Sugar: molecules containing carbon, oxygen, and hydrogen in a 1:2:1 ratio

91) Monosaccharide: the simplest carbohydrate acting alone or as a monomer for a disaccharide/polysaccharide; simple sugar

92) Disaccharide: two monosaccharides combined

93) Polysaccharide: more than two monosaccharides combined

94) Condensation (Dehydration Synthesis): thesynthes is of a disaccharide from two monosaccharides; the removal of water to form a new bond

95) Hydrolysis: a disaccharidess plitting into two monosaccharides with the addition of water

96) Starch: a polysaccharide made up of glucose molecules; used in plants for energy storage

97) Glycogen: an animal starch; stored mainly in the liver for energy in later uses; broken down into glucose

98) Cellulose: a structural polysaccharide of plant cell walls; glucose monomers joined together by β glycosidic linkages

99) Lignin: material in the cellulose matrix of plant cell walls that provide structural support

100) Saturated: when double bonds are gone in a solution; a molecule will not accept anymore hydrogens

101) Unsaturated: when carbon atoms have the potential to be joined by a double bonds; having the potential to bond in a solution

102) Phospholipid: the third carbon of glycerol molecule is occupied by a phosphate group attached to another polar group

103) Steroid: hydrophobic molecules; a lipid characterized by a carbon skeleton with four rings with various chemical groups attached

104) Peptide Bond: when the amino head of an amino acid is linked to the carbon tail of another amino acid with the removal of water (via condensation/dehydration synthesis); the creates of proteins; carboxyl group is linked to the amino group

105) Polypeptide: a polymer of amino acids linked by amino acids (ie: protein)

106) Primary Structure of a Protein: the number, kind, and order of amino acids joined by a peptide bond; always different depending on the protein produced

107) Secondary Structure of a Protein: often an α helix due to the numerous hydrogen bonds between the H and O in carboxyl and amino groups; every fourth amino acid

108) Tertiary Structure of a Protein: occurs when the α helix folds back on itself due to disulfide 3-d structural linkages

109) Quaternary Structure of a Protein: huge molecules (i.e.: hemoglobin) formed from interactions among R groups; the joining of large polypeptides

110) Nucleic Acid: consists of long chains of nucleotides (i.e.: DNA and RNA)

111) Nitrogenous Base: properties of a base in DNA and RNA; contains nitrogen

112) RNA: transcribes the genetic messages present in DNA; translates it into proteins (enzymes); a single polymer

113) DNA: primary component of chromosomes; carrier of genetic messages; codes for enzyme production; self-replicating; double helix structure

114) Purine: a two ring structure containing nitrogen (ie: adenine and guanine)

115) Pyrmidines: a single ring structure containing nitrogen (ie: cytosine, thymine, and uracil)

116) Enzymes: make energy by building and breaking down aka chemical reactions; globular proteins; chemical catalyst; lower the activation energy

117) Activation Energy: high kinetic energy where molecules bond and break; required for chemical reactions; lowered when the amount of enzymes are increased

118) Catalyst: a substance that lowers the activation energy needed for a chemical reaction

119) Metabolism: the totality of an organism’s chemical reactions (anabolic and catabolic) which manage the material and energy resources of an organism

120) Anabolism: a metabolic pathway that consumes energy to synthesize a complex molecule from simpler compounds

121) Catabolism: a metabolic pathway that release energy by breaking down complex molecules into simple compounds

122) Substrate: any substance altered by an enzyme

123) Active Site: one area of an enzyme that will react with a substrate

124) Cofactors: a non-protein substance that is used by enzymes for catalytic reactions


125) Biosphere: area on and around the Earth where life exists

126) Heterotroph: organisms dependent on outside sources for energy from organic substances

127) Autotroph: organisms that synthesize their own small building block molecules and energy by inorganic substances

128) Photosynthetic: gaining energy from light or the sun

129) Chemosynthetic: gaining energy from inorganic molecules

130) Cell Membrane: (Plasma Membrane) selectively permeable; controls the ease at which nutrients, waste, and other substances pass; a lipid bilayer (double phospholipid membrane) surrounding a cell’s inner workings

131) Chromosomes: dense groups of coiled chromatin that control the genetic makeup of cells

132) Histones: orderly packaged basic proteins associated with DNA; in all eukaryotes; octomer

133) Nucleus: most prominent structure in a cell holding the DNA and RNA; controls the functions of a cell; surrounded by a double membrane

134) Nuclear Membrane: (nuclear envelope) separates the nucleus from the rest of the cell; permeable

135) Nucleolus: site in the nucleus where ribosomes are created

136) Organelles: a cell’s organs

137) Cell Wall: plant cell membrane; acts as a pressure vessel preventing over- expansion when water enters the cell

138) Fluid-Mosaic Model: model of fatty acid tails and proteins moving through a membrane

139) Cytoskeleton: long protein strands that maintain cell size and shape

140) Microtubules: tubulin filaments from two particle proteins

141) Actin Filaments: (Microfilaments) thin filaments used in muscle contraction

142) Intermediate Filaments: composition differs amongst tissues

143) Vacuole: fluid-filled organelles storing enzymes and waste

144) Vesicle: a vacuole found in animals; smaller than a vacuole; created by the Golgi Bodies

145) Endoplasmic Reticulum: membrane-like tubes and sacs moving molecules

146) Golgi Bodies: (Golgi Complex or Golgi Apparatus) modifies proteins; releases vesicles

147) Lysosome: small spherical organelles that enclose hydrolytic enzymes within a single membrane

148) Peroxisome: a vesicle containing destructive enzymes

149) Mitochondria: large organelles that transfer energy from organic compounds into ATP

150) Chloroplast: chlorophyll-containing plasmids where photosynthesis occurs

151) Cilia: a type of microtubule that is short and numerous

152) Flagella: a type of microtubule that is long and few

153) Centrioles: involved in the reproduction in animal cells (meiosis); small cylindrical bodies

154) Prokaryote: cells w/o a nucleus; unicellular; few organelles w/ a nucleoid

155) Eukaryote: cells w/ a nucleus; multi-cellular; organelles enclosed by a membrane

156) SEM: (Scanning Electron Microscope) uses an electron beam to give a total magnification of 1000x; creates 3D image of the surface of a fixed organism

157) TEM: (Transmission Electron Microscope) electron beam goes through the fixed organism

158) Fixation: fixing organisms in place to see in a microscope

159) Cell: the basic unit of life; all living things are comprised of cells

160) Integral Protein: integrates through the protein

161) Cellulose: makes up the cell walls in eukaryotes but not prokaryotes; a polysaccharide; non-digestive

162) Cristae: the folded membrane inside the mitochondria; enlarges the surface area providing more space for the chemical reactions to occur

163) Nucleosome: created by an histone wrapped in DNA

Cell Memebrane

164) Diffusion: the movement of a substance from a higher concentration to lover concentration by means of random collision; without energy

165) Osmosis: the diffusion of water across a selectively permeable membrane; without energy

166) Homeostasis: the steady state physiological condition of the body

167) Solvent: the substance present in the greatest amount; the universal solvent is water

168) Solute: the substance that is the less present in a solution; the material being dissolved

169) Solution: a uniform mixture of two or more substances

170) Turgor Pressure: pressure within a cell created by diffusion of water by process of osmosis

171) Hypertonic: when concentration of solutes outside the cell is greater than inside the cell

172) Hypotonic: when the concentration of solutes inside the cell is greater than outside the cell; causes turgor pressure/swelling

173) Passive Transport: the movement of a substance from high concentration to low concentration without energy (i.e.: diffusion, osmosis, facilitated diffusion)

174) Active Transport: the movement of a substance against the concentration gradient (low concentration to high concentration); require the use of energy (i.e.: ATP)

175) Endocytosis: the process where cells take in molecules too large to pass through a membrane (i.e.: phagocytosis, pinocytosis, receptor-meditated endocytosis)

176) Exocytosis: vesicles formed in a Golgi Bodies reach the cell membrane and the contents are expelled

177) Photosynthesis: the conversion of light energy + CO2 + H2O into sugar and oxygen in plants

178) Respiration: the opposite of photosynthesis; uses sugar + oxygen to make ATP from mitochondria

179) Enzymes: a macromolecule serving as a catalyst; a chemical agent that changes the rate of a reaction without being consumed/altered by the reaction

180) ATP: used for endergonic reactions (those using energy); made from mitochondria

181) Water Potential: predicts the movement of water in and out of plant cells

182) Bulk Flow: when water or other fluids are induced to move because of pressure/gravity in the same direction

183) Osmotic Potential (Solute Potential): measures the effect of solutes in the direction of the movement of water

184) Pinocytosis: the movement of liquids with solutes and small particles into a cell


185) Mitosis: a process of nuclear division in eukaryotic cells; divided into four stages plus Interphase;

186) Cytokinesis: the division of the cytoplasm to form two separate daughter cells immediately after mitosis

187) Chromatid: a strand that makes up a chromosome; copies itself to equal chromosome; called “sister”

188) Chromosome: a cellular structure carrying genetic material found in the nucleus of all eukaryotic cells; holds hereditary information and cell function

189) Centromere: the specialized region of a chromosome where two chromatids are attached

190) Cell Cycle: an ordered sequence of events in the life of a cell, from its origin in the division of a parent cell until its own division (mitosis); eukaryotic cells experience interphase and M phase

191) G1 Phase: cell prepares for DNA replication; doubles in cell volume; diploid (2n = 46 chromosomes)

192) S Phase: the DNA is replicated

193) G2 Phase: the cell prepares to divide during M phase

194) Spindle: fanlike microtubules structure that helps separate the chromosomes into chromatid (again)

195) Aster: a radical array of short microtubules that extend from each centrosome toward the plasma membrane in an animal cell undergoing mitosis

196) Centrioles: a structure in the centrosomes of an animal cell composed of cylinder of microtubule triplets (9 + 0); two in each centrosome

197) Interphase: 90% of the cycle 

198) Prophase: the longest phase of mitosis

199) Metaphase: the second stage of mitosis; the spindles are complete, and the chromosomes are aligned in the middle and are attached by the centromere to the spindles

200) Anaphase: the third stage of mitosis; the chromatids are split apart – pulled to either pole of the cell

201) Telophase: the fourth stage of mitosis; cytokinesis has begun and daughter cells begin to form

202) Chromatin: the complex of DNA and proteins that make up a eukaryotic cell; when a cell is not undergoing division, chromatin exists in a disperse form – thin fibers not visible under a light microscope

203) Centrosome: the structure present in the cytoplasm of animals cells; functions as a microtubule-organizing center holding the two centrioles

204) Clone: a lineage of identical cells/individuals; to make more genetically similar organisms; when the post-other that is identical to the pre-other

205) Cytoplasm: contents of the cell exclusive to the cell nucleus and contained by the plasma (cell) membrane

Cell Respiration

206) Glycolysis: splitting glucose into two molecules of pyruvic acid; occurring in the cytoplasm

207) Cell Respiration: takes sugar (glucose) and oxygen into the mitochondria to make ATP

208) Krebs Cycle: (citric acid cycle) a series of reactions that break down glucose by oxidating the pyruvic acid to CO2 creating the 6-carbon molecule citrate

209) Electron Transport: makes a total of 34 ATP and H2O; occurs in the mitochondria where an electron carrier molecule shuttles electrons during redox reactions releasing energy used to make ATP *Redox Reactions: a chemical reaction where an electron is lost and an electron is gained

210) Fermentation: the partial degradation of sugars in the body that occur w/ the lack of oxygen; lactic acid fermentation and alcoholic fermentation occur as anaerobic respirations; no yield of ATP

211) Matrix: a compartment in the mitochondria where enzymes are located for the ETS to make ATP; location of a mitochondria’s DNA and ribosomes

212) Electron Transport System: third stage of cell respiration; produces 34 ATP; a collection of molecules embedded in the inner membrane of the mitochondria (matrix) – in eukaryotes

213) Oxidative – Phosphorylation: oxidizes (adds an oxygen molecule) nutrients and phosphorylates (adds a phosphate) ADP to make ATP

214) Enzymes: makes energy by catabolic reactions or starts chemical reactions through anabolic means; lowers the activation energy; a globular protein and chemical catalyst

215) Glucose: a 6-carbon sugar used in Glycolysis to make 2 ATP and 2 pyruvic acids

216) Lactic Acid Fermentation: occurs w/o the availability of oxygen; anaerobic effect after Glycolysis that converts the pryuvates into lactic acid (lactate) w/o the release of CO2

217) NAD+: (nicotinamide adenine dinucleotide) a coenzyme that accepts an electron and acts as an electron carrier in the ETS; used in creating a proton gradient (chemiosmosis)

218) NADH: made in Glycolysis; worth 3 ATP in the ETS

219) FADH2: (flavin adenine dinucleotide) two are made in the Krebs Cycle and are worth 2 ATP individually in the ETS

220) ATP: (adenine triphosphate) an energy molecule that is produced by the mitochondria; used by cells as an energy source; 38 are made total in cell respiration; used in photosynthesis to create glucose

221) Crista: (plural: Cristae) inner membrane of the mitochondria that houses the electron transport chains and molecules of the enzyme catalyzing the synthesis of ATP (ATP synthase)


222) Photons: a discrete amount of light energy that behaves as if it were a particle

223) Absorption Spectrum: the range of a pigment’s ability to absorb various wavelengths of light

224) Thylakoid: a flattened membranous sac inside a chloroplast; exist in an interconnected systemin the chloroplasts and contain the molecule “machinery” used to convert light into chemical energy

225) Stroma: located in the chloroplast, the dense fluid surrounds thylakoid membranes; involved in the synthesis of organic molecules from CO2 to H2O

226) Grana: (singular: Granum) a stack of thylakoids in chloroplast; function in the light– dependent reactions of photosynthesis

227) Fixation of Carbon: the initial incorporation of carbon from CO2 into an organic compound by an autotrophic organism

228) Photophosphorlyation: the process of generating ATP from ADP and a phosphate by means of a proton-motive force generated across the thylakoid membrane of chloroplast during light-reactions of photosynthesis

229) Cyclic Electron Flow: a route of electron flow during the light reactions of photosynthesis that involve only Photosystem I; produces ATP but not NADPH or O2 

230) Stomata: a microscopic pore surrounded by guard cells in the epidermis of leaves and stems; allows gas exchanges between the environment and interior of the plant

231) Hatch-Slack Pathway: occurs before the Calvin cycle; converts CO2 into a four- carbon sugar before releasing it into the Calvin Cycle; uses more ATP to create glucose but photosynthesis occurs at a faster, more direct, rate

232) NADPH2: [NADP+ + H = NAPH2] temporarily stores energized electrons produced during light reactions

233) Calvin Cycle: the second phase of photosynthesis – after light–dependent reactions – involves the fixation of CO2 from the atmosphere and reduction of fixed carbon into a carbohydrate (redox reaction)

234) Photorespiration: consumes O2 and ATP releasing CO2 and decreasing photosynthetic output; usually occurs on hot, dry, bright days when a plant’s stomata closes; [O2 concentration is > than the CO2 concentration]

235) CAM Plants: plants that adapt for photosynthesis by means of crassulacean acid metabolism – acidic conditions; CO2 enters the stomata at night and is converted into organic acids releasing CO2 for the Calvin cycle in the day

236) C4 Plants: a plant in which the Calvin Cycle is preceded (skipped) by reaction that incorporate the CO2 into a 4-carbon compound; the end product of the reaction supplies CO2 for the Calvin cycle MEISOIS

237) Meiosis: a modified type of cell division in sexually reproducing organisms consisting of two rounds of cell division but only one round of DNA replication; results in cells with half the number of chromosomes from the original cell (haploids)

238) Haploid: (monoploid) a cell containing one set of the chromosomes from the original cell(s); determined as “n”

239) Diploid: a cell containing two sets of chromosomes; one set inherited from each parent cell; determined as “2n”

240) Tetraploid: a cell containing four sets of chromosomes; at the end of interphase, chromosomes copy each other; determined as “4n”

241) Polyploid: any chromosome number more than “2n”

242) Fertilization: the union of haploid gametes to produce a diploid cell (sperm + egg = zygote)

243) Zygote: the diploid product of the union of haploid gametes during fertilization; a fertilized egg

244) Homologues: a pair of chromosomes of the same length, centromere position, and staining pattern that possess genes for the same characters at corresponding loci

245) Alternations of Generations: haploid life phase is followed by a diploid life phase

246) Spore: the life cycle of a plant or alga undergoing alternation of generations a haploid cell produced in the sporophyte by meiosis; can divide by mitosis to develop into a multicellular haploid individual – the gametophyte – without fusing to another cell;

247) Tetrad: composed of two homologous chromosomes with two chromatids; fourtota l chromatids

248) Synapsis: the pairing and physical connection of replicated homologous chromosomes during prophase I of meiosis

249) Crossing Over: the reciprocal exchange of genetic material between non-sister chromatids during prophase I of meiosis

250) Gametes: a haploid reproductive cell (i.e.: egg or sperm) that unite during sexual reproduction to produce a diploid zygote

251) Mitosis: a process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, metaphase, anaphase, and telophase; conserves chromosomes number by allocating replicated chromosomes equally to each of the daughter nuclei

252) Polar Body: a small cell containing little cytoplasm that is produced along with the oocyte and later discarded

253) Sperm: the male gamete

254) Ova: the female gamete