AP Bio ultimate review (Units 1-8)

UNIT 1: Chemistry of Life

Biomolecules – Large molecules essential for life, including carbohydrates, lipids, proteins, and nucleic acids.
Water – Polar molecule essential for life, with unique properties like cohesion, adhesion, and high specific heat.
Carbohydrates – Organic compounds composed of carbon, hydrogen, and oxygen; primary source of energy.
Lipids – Hydrophobic molecules used for energy storage, membrane structure, and signaling.
Proteins – Polymers of amino acids; responsible for structure, function, and regulation of tissues and organs.
Amino Acids – Building blocks of proteins; consist of a central carbon, an amino group, a carboxyl group, and a variable R group.
Enzymes – Proteins that catalyze biochemical reactions by lowering activation energy.
Nucleic Acids – DNA and RNA; store and transmit genetic information.
DNA – Deoxyribonucleic acid; molecule that carries genetic information.
RNA – Ribonucleic acid; involved in protein synthesis and gene regulation.
Nucleotide – Building blocks of nucleic acids; composed of a sugar, phosphate group, and nitrogenous base.
Hydrogen Bonding – Weak bonds between hydrogen and electronegative atoms (e.g., oxygen); important in DNA structure and water properties.
pH – Measure of the concentration of hydrogen ions in a solution; affects enzyme activity and chemical reactions.
Dehydration Synthesis – Chemical reaction in which two molecules are joined by removing a water molecule.
Hydrolysis – Reaction in which water is added to break down a molecule into smaller units.

UNIT 2: Cell Structure and Function

Prokaryotic Cells – Cells without a nucleus or membrane-bound organelles (e.g., bacteria).
Eukaryotic Cells – Cells with a nucleus and membrane-bound organelles (e.g., plant and animal cells).
Plasma Membrane – Phospholipid bilayer that separates the cell’s interior from the outside environment.
Cytoplasm – Gel-like substance inside the cell where organelles are located; site of metabolic reactions.
Nucleus – Membrane-bound organelle containing the cell’s DNA and controlling gene expression.
Mitochondria – Organelles responsible for energy production through cellular respiration.
Chloroplasts – Organelles in plant cells that conduct photosynthesis.
Endoplasmic Reticulum (ER) – Network of membranes involved in protein and lipid synthesis.
Golgi Apparatus – Organelles that modify, sort, and package proteins and lipids for transport or secretion.
Lysosomes – Membrane-bound organelles containing enzymes that break down waste materials and cellular debris.
Ribosomes – Structures responsible for protein synthesis, found in the cytoplasm or attached to the rough ER.
Cytoskeleton – Network of protein fibers that provides structural support, shape, and movement to cells.
Cell Wall – Rigid outer layer of plant, fungal, and bacterial cells, providing structure and protection.
Vesicles – Membrane-bound sacs used to transport materials within or outside the cell.
Endocytosis – Process by which cells engulf extracellular material by wrapping the plasma membrane around it.
Exocytosis – Process by which cells expel materials through vesicles fusing with the plasma membrane.

UNIT 3: Cellular Energetics

ATP (Adenosine Triphosphate) – Main energy currency of the cell, used in various biochemical processes.
Cellular Respiration – Process by which cells break down glucose to produce ATP.
Glycolysis – First stage of cellular respiration; breakdown of glucose into pyruvate, producing a small amount of ATP.
Citric Acid Cycle (Krebs Cycle) – Second stage of cellular respiration; occurs in mitochondria and produces high-energy electron carriers.
Electron Transport Chain – Final stage of cellular respiration; generates ATP through oxidative phosphorylation.
Fermentation – Anaerobic process that allows cells to generate ATP when oxygen is unavailable.
Photosynthesis – Process by which plants, algae, and some bacteria convert light energy into chemical energy.
Chlorophyll – Green pigment in chloroplasts that absorbs light energy for photosynthesis.
Light-dependent Reactions – Stage of photosynthesis where sunlight is used to produce ATP and NADPH.
Calvin Cycle – Light-independent reactions of photosynthesis; converts carbon dioxide into glucose using ATP and NADPH.
Enzyme-Substrate Complex – Temporary molecule formed when an enzyme binds to its substrate.
Activation Energy – The energy required to start a chemical reaction.
Feedback Inhibition – Regulatory mechanism in which the end product of a pathway inhibits an enzyme involved earlier in the pathway.

UNIT 4: Cell Communication and Cell Cycle

Signal Transduction Pathways – Processes by which a cell responds to external signals through a series of molecular events.
Receptors – Proteins that receive and bind to signaling molecules, initiating cellular responses.
G-Protein Coupled Receptors (GPCRs) – Membrane receptors that activate G proteins in response to signaling molecules.
Tyrosine Kinase Receptors – Membrane receptors that phosphorylate tyrosine residues to trigger signaling pathways.
Cyclic AMP (cAMP) – Second messenger molecule involved in the activation of signal transduction pathways.
Apoptosis – Programmed cell death; essential for development and maintaining cellular health.
Mitosis – Process of cell division that results in two genetically identical daughter cells.
Meiosis – Type of cell division that produces gametes (sperm and egg), reducing the chromosome number by half.
Cell Cycle – Series of stages (G1, S, G2, and M) that a cell goes through to divide.
Interphase – Stage of the cell cycle where the cell grows, replicates DNA, and prepares for division.
Prophase – First stage of mitosis where chromatin condenses into chromosomes.
Metaphase – Stage of mitosis where chromosomes align in the center of the cell.
Anaphase – Stage of mitosis where sister chromatids are pulled apart toward opposite poles.
Telophase – Final stage of mitosis where the nuclear envelope reforms around the separated chromatids.
Cytokinesis – Division of the cytoplasm and organelles between daughter cells at the end of mitosis.
Checkpoints – Regulatory points in the cell cycle that ensure proper cell division and DNA integrity.
Cyclins and Cyclin-dependent Kinases (CDKs) – Proteins that regulate the progression of the cell cycle.

UNIT 5: Heredity and Genetics

Gene – Unit of heredity, a sequence of DNA that codes for a protein or RNA.
Alleles – Different forms of a gene that may produce variations in traits.
Homozygous – Having two identical alleles for a particular gene.
Heterozygous – Having two different alleles for a particular gene.
Genotype – Genetic makeup of an organism; combination of alleles for a given trait.
Phenotype – Observable traits of an organism resulting from its genotype.
Punnett Square – Tool used to predict the genotypes and phenotypes of offspring from two parents.
Mendel’s Laws of Inheritance – Principles of heredity based on Gregor Mendel's experiments with pea plants: Law of Segregation and Law of Independent Assortment.
Law of Segregation – Mendel's law stating that each allele for a gene separates into different gametes.
Law of Independent Assortment – Mendel's law stating that genes for different traits are inherited independently of each other.
Codominance – A type of inheritance in which both alleles for a gene are fully expressed.
Incomplete Dominance – A type of inheritance where the heterozygous phenotype is an intermediate blend of the two homozygous phenotypes.
Polygenic Inheritance – Inheritance pattern where multiple genes contribute to a single trait.
Sex-linked Traits – Traits controlled by genes located on sex chromosomes, often exhibiting different inheritance patterns in males and females.
X-inactivation – Process by which one X chromosome in female mammals is randomly inactivated.

UNIT 6: Molecular Genetics

DNA Replication – Process of copying DNA before cell division; ensures each daughter cell has identical genetic material.
DNA Polymerase – Enzyme that synthesizes new DNA strands during replication.
Helicase – Enzyme that unwinds the DNA double helix ahead of the replication fork.
Ligase – Enzyme that joins Okazaki fragments on the lagging strand during DNA replication.
Okazaki Fragments – Short segments of DNA synthesized on the lagging strand during replication.
Transcription – Process by which an RNA molecule is synthesized from a DNA template.
RNA Polymerase – Enzyme that synthesizes RNA during transcription.
mRNA (messenger RNA) – RNA molecule that carries genetic information from the DNA to the ribosome for protein synthesis.
Codon – A sequence of three nucleotides in mRNA that codes for a specific amino acid.
tRNA (transfer RNA) – RNA that brings amino acids to the ribosome during translation.
Ribosome – Organelles that facilitate protein synthesis by reading mRNA and linking amino acids.
Translation – Process by which mRNA is translated into a sequence of amino acids to form a protein.
Mutations – Changes in the DNA sequence that can lead to genetic variation or disorders.
Point Mutation – Mutation involving a single nucleotide; can lead to a change in the amino acid sequence.
Frameshift Mutation – Mutation that shifts the reading frame of the mRNA, usually causing significant changes in the protein.
Operon – Cluster of genes in prokaryotes regulated by a single promoter; includes an operator, promoter, and structural genes.
Lac Operon – An operon involved in the metabolism of lactose in bacteria; regulated by lactose availability.
Epigenetics – Study of changes in gene expression caused by mechanisms other than changes in the DNA sequence.
Histone Modification – Chemical modifications to histone proteins that affect DNA packaging and gene expression.
RNA Splicing – Process of removing introns from pre-mRNA and joining exons together to form mature mRNA.
Introns – Non-coding regions of mRNA that are removed during RNA splicing.
Exons – Coding regions of mRNA that remain after splicing and are translated into protein.

UNIT 7: Natural Selection

Natural Selection – Process by which individuals with advantageous traits survive and reproduce more effectively than those without.
Fitness – Measure of an organism's ability to survive, reproduce, and pass on its genes.
Adaptation – Inherited trait that increases an organism’s chances of survival and reproduction in a specific environment.
Variation – Differences in traits among individuals in a population, which can arise through mutation or recombination.
Survival of the Fittest – Concept that organisms best adapted to their environment are more likely to survive and reproduce.
Artificial Selection – Human-directed breeding of organisms to produce desired traits.
Genetic Drift – Random changes in allele frequencies in a population due to chance events.
Bottleneck Effect – Type of genetic drift resulting from a drastic reduction in population size, leading to a loss of genetic diversity.
Founder Effect – Genetic drift occurring when a small group of individuals establishes a new population with limited genetic diversity.
Gene Flow – Movement of alleles between populations due to migration of individuals.
Directional Selection – Natural selection that favors one extreme phenotype in a population.
Stabilizing Selection – Natural selection that favors intermediate phenotypes and reduces variation.
Disruptive Selection – Natural selection that favors both extreme phenotypes, leading to increased variation.
Sexual Selection – Form of natural selection where traits that increase an individual’s chances of attracting mates are favored.
Speciation – Process by which new species arise from an existing population.
Allopatric Speciation – Speciation that occurs when populations are geographically isolated from each other.
Sympatric Speciation – Speciation that occurs without geographic isolation, often through behavioral or ecological factors.

UNIT 8: Ecology

Ecosystem – A community of organisms interacting with their physical environment, including both biotic and abiotic factors.
Biosphere – The global sum of all ecosystems; the region of Earth where life exists.
Biotic Factors – Living components of an ecosystem, such as organisms and their interactions.
Abiotic Factors – Non-living components of an ecosystem, including temperature, light, water, and soil.
Niche – The role and position of a species within its environment, including its interactions with other species and its habitat.
Trophic Levels – The hierarchical levels in an ecosystem, based on an organism's source of energy (e.g., producers, primary consumers, secondary consumers).
Producers (Autotrophs) – Organisms that produce their own food, typically through photosynthesis or chemosynthesis.
Consumers (Heterotrophs) – Organisms that rely on other organisms for food; include herbivores, carnivores, omnivores, and decomposers.
Primary Producers – Organisms that produce energy-rich compounds used by other organisms in an ecosystem (e.g., plants, algae).
Food Chain – Linear sequence showing energy flow from one organism to another in an ecosystem.
Food Web – A complex network of interconnected food chains in an ecosystem.
Energy Pyramid – A diagram representing the energy flow through trophic levels in an ecosystem, with energy decreasing at each level.
Biogeochemical Cycles – The movement of elements and compounds through living organisms and the environment (e.g., carbon, nitrogen, water cycles).
Carbon Cycle – The process by which carbon is exchanged between the atmosphere, land, and organisms.
Nitrogen Cycle – The process by which nitrogen is converted into different forms, such as nitrates, ammonia, and nitrogen gas, by bacteria and other organisms.
Water Cycle – The continuous movement of water through the environment via processes like evaporation, condensation, precipitation, and runoff.
Carrying Capacity – The maximum number of individuals of a species that an environment can support indefinitely.
Exponential Growth – Growth of a population that occurs at a constant rate, resulting in a J-shaped curve.
Logistic Growth – Population growth that slows as it approaches the carrying capacity of the environment, resulting in an S-shaped curve.
K-selected Species – Species that produce fewer offspring but invest more resources in their upbringing, leading to a stable population size.
r-selected Species – Species that produce many offspring with little investment in their care, leading to rapid population growth.

UNIT 9: Growth and Development

Cellular Differentiation – Process by which unspecialized cells become specialized in structure and function.
Stem Cells – Undifferentiated cells capable of giving rise to various cell types.
Totipotent Cells – Cells capable of differentiating into any cell type, including the embryonic tissues.
Pluripotent Cells – Cells that can differentiate into many, but not all, cell types; typically found in the early stages of embryonic development.
Multipotent Cells – Cells that can differentiate into a limited number of cell types, often specific to a particular tissue or organ.
Germ Layers – Three primary layers (ectoderm, mesoderm, endoderm) formed during early development that give rise to different tissues and organs.
Fertilization – The fusion of sperm and egg to form a zygote, initiating the development of a new organism.
Cleavage – Early cell division in the zygote, leading to the formation of a blastula.
Blastocyst – Stage of mammalian embryonic development where a hollow ball of cells is formed, which implants into the uterine wall.
Gastrulation – Process by which the blastocyst forms the three germ layers (ectoderm, mesoderm, endoderm).
Organogenesis – The process of forming organs from the three germ layers during embryonic development.
Homeotic Genes – Genes that control the development of body structures in animals; mutations in these genes can result in abnormal development.
Induction – The process by which one group of cells influences the development of another group through signaling.
Apoptosis – Programmed cell death, essential for development and the elimination of damaged or unneeded cells.