Unit Summaries for Biology Concepts - 11th Grade

Unit 1: Chemistry of Life
  • Polarity: Molecules have a slight charge, leading to unique interactions.
  • Hydrogen Bonds: Weak attractions between molecules, crucial for water's properties.
  • Cohesion/Adhesion: Cohesion is water's attraction to itself; adhesion is attraction to other substances.
  • Surface Tension: A measure of how difficult it is to stretch or break the surface of a liquid.
  • High Specific Heat: Water can absorb a lot of heat before changing temperature, helping to stabilize environments.
  • Solvent: Water's ability to dissolve many substances, making it essential for biological processes.
  • Macromolecules: Major classes of biological molecules: carbohydrates, lipids, proteins, and nucleic acids.
  • Monomer/Polymer: Monomers are single units (like sugars); polymers are chains of monomers (like starch).
  • Dehydration Synthesis: Process of joining two molecules by removing water.
  • Hydrolysis: Breaking down molecules by adding water.
  • Enzyme: Proteins that speed up biochemical reactions by lowering activation energy.
  • Active Site: The part of an enzyme where the substrate binds.
  • Substrate: The molecule an enzyme acts upon.
  • Denaturation: Loss of an enzyme's shape and activity due to factors like temperature and pH.
Unit 2: Cell Structure and Function
  • Prokaryote vs. Eukaryote: Prokaryotes are simple, single-celled organisms; eukaryotes are complex, with membrane-bound organelles.
  • Plasma Membrane: The cell's outer boundary, controlling what enters and exits.
  • Selective Permeability: The membrane's ability to allow some substances through while blocking others.
  • Phospholipid Bilayer: The structure of the plasma membrane, with hydrophilic heads and hydrophobic tails.
  • Transport:
    • Diffusion: Movement of particles from higher to lower concentration.
    • Osmosis: The diffusion of water across a semipermeable membrane.
    • Facilitated Diffusion: Movement of substances through protein channels without energy.
    • Active Transport: Movement against the concentration gradient, requiring energy.
  • Endocytosis/Exocytosis: Processes of taking substances into (endocytosis) and out of (exocytosis) the cell.
  • Organelles: Cellular structures like the nucleus, ribosome, mitochondrion, ER, Golgi apparatus, lysosome, chloroplast, each with specific functions.
  • Surface Area-to-Volume Ratio: An important factor for cellular efficiency; larger ratios mean better exchange of materials.
  • Fluid Mosaic Model: Description of the cell membrane as a flexible structure with various proteins embedded.
Unit 3: Cellular Energetics
  • Enzyme: A catalyst speeding up reactions in cellular processes.
  • Substrate Specificity: Enzymes are specific to their substrates.
  • Catalyst: A substance that increases the rate of a chemical reaction without being consumed.
  • Competitive/Noncompetitive Inhibition: Ways in which an inhibitor can decrease enzyme activity.
  • Cellular Respiration:
    • Glycolysis: First step of cellular respiration breaking glucose into pyruvate.
    • Krebs Cycle: Produces electron carriers from pyruvate.
    • Electron Transport Chain (ETC): Series of proteins that produce ATP using electrons and oxygen as the final acceptor.
  • Chemiosmosis: The process of ATP generation using a hydrogen ion gradient.
  • Photosynthesis:
    • Light Reactions: Convert solar energy to chemical energy.
    • Calvin Cycle: Uses ATP and NADPH to produce glucose.
    • Thylakoid, Chlorophyll, Stroma: Structures and components involved in photosynthesis.
  • NADH/NADPH: Electron carriers used in cellular respiration and photosynthesis, respectively.
Unit 4: Cell Communication and Cell Cycle
  • Signal Transduction Pathway: Sequence of processes by which a cell responds to a signal molecule.
  • Ligand: A signaling molecule that binds to a receptor.
  • Receptor: A protein that receives and responds to signals.
  • Secondary Messenger: Molecules that relay signals inside the cell.
  • Feedback Loop: Mechanisms (positive or negative) that maintain homeostasis.
  • Mitosis:
    • Phases: Interphase, prophase, metaphase, anaphase, telophase.
  • Cytokinesis: Division of the cytoplasm after mitosis.
  • Cell Cycle Checkpoints: Points that monitor the cell cycle and prevent inappropriate division.
  • Cyclins/CDKs: Proteins that regulate the cell cycle.
  • Apoptosis: Programmed cell death, important for development and homeostasis.
Unit 5: Heredity
  • Gene: A unit of heredity that influences traits.
  • Allele: Different forms of a gene.
  • Dominant/Recessive: Terms describing allele expression.
  • Genotype/Phenotype: Genotype is the genetic makeup; phenotype is the expressed traits.
  • Homozygous/Heterozygous: Homozygous has identical alleles; heterozygous has different alleles for a trait.
  • Punnett Square: A tool to predict genetic combinations.
  • Monohybrid/Dihybrid Cross: One trait vs. two trait crosses in genetics.
  • Law of Segregation: Alleles for a trait separate during gamete formation.
  • Law of Independent Assortment: Genes for different traits are inherited independently.
  • Meiosis: Cell division that produces gametes with half the chromosomes.
  • Crossing Over: Exchange of genetic material between homologous chromosomes, increasing genetic diversity.
  • Linked Genes: Genes located on the same chromosome and inherited together.
  • Sex-Linked Inheritance: Traits associated with genes located on sex chromosomes.
  • Pedigree: A diagram showing the lineage of a trait within families.
Unit 6: Gene Expression and Regulation
  • DNA/RNA: Genetic material (DNA) and its messenger (RNA).
  • Nucleotide: Building blocks of DNA and RNA.
  • Replication: Process of copying DNA.
  • Transcription: Synthesis of RNA from a DNA template.
  • Translation: Process of synthesizing proteins from RNA.
  • Codon/Anticodon: Triplet of nucleotides that specifies an amino acid (codon) and its complement on tRNA (anticodon).
  • RNA Types:
    • mRNA: Messenger RNA carrying genetic information.
    • tRNA: Transfer RNA bringing amino acids to the ribosome.
    • rRNA: Ribosomal RNA that forms part of the ribosome's structure.
  • Ribosome: The site of protein synthesis.
  • Start/Stop Codon: Signals the beginning and end of translation.
  • Promoter: A DNA sequence that initiates transcription of a gene.
  • Operon (lac/trp): Groups of genes regulated together in prokaryotes.
  • Repressor: A protein that inhibits gene expression.
  • Mutation: Changes in DNA sequence, such as missense, nonsense, silent, and frameshift mutations.
  • Biotechnology: Techniques such as PCR, gel electrophoresis, and transformation.
Unit 7: Natural Selection
  • Evolution: Change in characteristics of a species over generations.
  • Natural Selection: Process by which organisms better adapted to their environment survive and reproduce.
  • Adaptation: Trait that enhances survival and reproduction.
  • Fitness: An organism's ability to survive and reproduce.
  • Genetic Drift: Random changes in allele frequencies in a population.
  • Gene Flow: Movement of genes between populations.
  • Bottleneck Effect: A loss of genetic diversity due to a significant reduction in population size.
  • Founder Effect: Reduced genetic diversity when a few individuals start a new population.
  • Speciation: Formation of new species.
  • Reproductive Isolation: Barriers that prevent mating between species.
  • Homologous Structures: Similar structures in different species indicating common ancestry.
  • Analogous Structures: Similar functions in different species, not due to common ancestry.
  • Phylogenetic Tree: Diagram showing evolutionary relationships.
  • Cladogram: A branching diagram showing evolutionary relationships based on shared characteristics.
  • Hardy-Weinberg Equilibrium: A principle that describes gene equilibrium in a non-evolving population (p² + 2pq + q²).
Unit 8: Ecology
  • Ecosystem: A biological community interacting with its environment.
  • Population: A group of individuals of the same species in a given area.
  • Community: All living populations in an area.
  • Producers/Consumers/Decomposers: Trophic roles in ecosystems: producers create energy, consumers eat producers, decomposers recycle matter.
  • Food Chain/Web: The flow of energy and nutrients through an ecosystem.
  • Trophic Levels: The hierarchical levels in a food chain.
  • Energy Pyramid: A model showing energy loss at each trophic level (10% rule).
  • Carrying Capacity: Maximum population size an environment can sustain.
  • Limiting Factor: Environmental condition that limits the growth of a population.
  • Symbiosis: Interaction between species (mutualism, parasitism, commensalism).
  • Biogeochemical Cycles: Pathways by which elements move through ecosystems (carbon, nitrogen, water).
  • Keystone Species: A species that has a disproportionately large effect on its environment.
  • Invasive Species: Non-native species that disrupt local ecosystems.