AP BIOLOGY REVIEW ✨

AP Biology Curriculum Recap

Introduction
  • Presenter: Melanie King from Absolute Recap
  • Purpose: Recap the entire AP Biology curriculum, covering all eight units. This guide includes essential terms, concepts, and equations needed for the exam.
  • Study Strategy: Use a triage method to prioritize study topics.
    • Emergency room analogy: Just as doctors triage patients, students should prioritize study topics.
    • Use a color coding system:
      • Green: Topics fully understood.
      • Yellow: Familiar but not fully remembered.
      • Red: Topics not learned or understood.
  • Final Study Focus:
    • Prioritize reds first, then yellows, skip greens since those are already known.
    • Resources are available in the description for further study.
Unit One: Chemistry of Life
  • Importance of Water:
    • Water (H₂O) is a polar molecule forming hydrogen bonds.
    • Properties of water due to hydrogen bonding:
      • Cohesion
      • Adhesion
      • Surface tension
      • High specific heat
      • Universal solvent
  • Common Elements in Biological Molecules:
    • Elements: Carbon (C), Hydrogen (H), Nitrogen (N), Oxygen (O), Phosphorus (P), Sulfur (S)
  • Categories of Biological Molecules:
    • Carbohydrates:
      • Ratio of C:H:O is 1:2:1.
      • Structures: Rings or long chains.
      • Monomers: Often end in -OSE.
      • Functions: Energy storage (short and long-term), structural materials.
    • Lipids:
      • Non-polar, consist of hydrocarbon chains and steroid rings.
      • Hydrogen to oxygen ratio greater than 2:1.
      • Fatty acid tails: Saturated or unsaturated, affecting phospholipid bilayer fluidity.
    • Proteins:
      • Composed of polypeptides formed by amino acid monomers.
      • Structure determined by folding due to hydrogen bonding and R-group interactions.
      • Functions: Diverse roles including enzymes, transport channels, and receptors.
    • Nucleic Acids:
      • Formed from nucleotide monomers.
      • Focus on DNA and RNA in Unit Six.
  • Formation of Biological Molecules:
    • Synthesis through dehydration reactions.
    • Breakdown through hydrolysis reactions.
Unit Two: Cell Structure and Function
  • Types of Cells:
    • Prokaryotic vs. Eukaryotic cells.
    • Size constraints: Smaller cells have a higher surface area to volume ratio, enhancing efficiency.
  • Eukaryotic Organelles:
    • Majority are membrane-bound, several associated with endomembrane system (e.g., rough ER, smooth ER, Golgi apparatus).
    • Ribosomes: Not membrane-bound; made of rRNA and protein.
    • Mitochondria and chloroplasts: Double membranes; excluded from endomembrane system due to endosymbiosis theory.
  • Transport Mechanisms:
    • Emphasis on solute concentration, not quantity.
    • Comparative terminology: Hypertonic, isotonic, hypotonic.
    • Active Transport:
      • Requires ATP.
      • Moves large or charged molecules against their gradient via proteins.
    • Passive Transport:
      • Moves small, non-polar molecules down their concentration gradient via diffusion or facilitated diffusion.
    • Osmosis:
      • Water movement according to its own gradient (water potential), sometimes through aquaporins.
    • Endocytosis/Exocytosis:
      • Mechanisms for larger molecule transport across membranes.
Unit Three: Cellular Energetics
  • Focus on energy flow in cellular processes.
  • Enzymes:
    • Made of proteins, possess an active site for substrate binding.
    • Reduce activation energy needed for reactions but do not change energy difference between reactants and products.
    • Enzymes can be denatured or inhibited by environmental factors.
  • Photosynthesis:
    • Captures light energy via chlorophyll, facilitates the formation of a three-carbon molecule.
    • Light Reactions: Occur in thylakoid membranes.
    • Calvin Cycle: Takes place in stroma.
  • Cellular Respiration:
    • Process of glucose oxidation in the presence of oxygen, creating an electrochemical gradient of hydrogen ions that generates ATP.
    • Glycolysis: Takes place in cytoplasm.
    • Krebs Cycle: Occurs in mitochondrial matrix.
    • Electron Transport Chain: Located in cristae.
    • Fermentation: Occurs in absence of oxygen to regenerate NADH for glycolysis.
  • Key Concept: Mitochondria synthesize ATP through oxidative phosphorylation, not merely as the "powerhouse" of the cell.
  • Emphasize that plants perform both photosynthesis and cellular respiration, housing both organelles.
  • Fitness:
    • Definition: Organisms best suited to their environment tend to reproduce more successfully, passing on their genotype.
Unit Four: Cell Communication and Cell Cycle
  • Cell Communication:
    • Types: Autocrine, paracrine, and endocrine signaling based on message distance.
    • Reception via ligand binding triggers signal transduction pathways.
    • Signal transduction involves three steps:
      • Reception (often through protein modification)
      • Transduction (signal amplification via phosphorylation)
      • Response (varied outcomes including gene expression or apoptosis)
    • Conveys similarity to enzyme-substrate relationships; pathways are ligand-specific.
    • Positive feedback (moves process away from homeostasis) vs. negative feedback (returns and maintains homeostasis).
  • Cell Cycle:
    • Phases: Interphase (G1, sometimes G0, S phase, G2), followed by mitosis (prophase, metaphase, anaphase, telophase).
    • Mitosis produces identical daughter cells through the division of sister chromatids.
    • Cytokinesis follows mitosis, dividing cytoplasm between the cells.
    • Regulation involves cyclins and CDKs with checkpoints monitoring for DNA damage, replication integrity, and spindle attachment.
Unit Five: Heredity
  • Focus on meiosis as the process for forming unique gametes for sexual reproduction.
    • Meiosis involves two rounds of division (PMAP).
    • Homologous chromosomes observable in metaphase one; creates genetic diversity through crossing over and independent assortment.
    • Chromosomal disorders may arise from nondisjunction, deletion, inversion, and translocation.
  • Inheritance Patterns:
    • Mendelian Genetics:
      • Example ratios: 3:1 for monohybrid crosses, 9:3:3:1 for dihybrids.
    • Non-Mendelian Genetics:
      • Types: Incomplete dominance, co-dominance, linked genes, sex-linked traits.
    • Practice using Punnett squares and pedigrees; review rules of probability and chi-square analysis.
Unit Six: Gene Expression and Regulation
  • Previously discussed nucleic acids (DNA and RNA) with genetic information.
    • DNA: Double-stranded, deoxyribose, bases (A, T, C, G).
    • RNA: Single-stranded, ribose, base uracil replacing thymine.
    • Base pairing: A with T (or U), C with G (two and three hydrogen bonds, respectively).
  • DNA Replication:
    • Enzyme: DNA polymerase, synthesizes in 5' to 3' direction.
    • Anti-parallel strands, continuous on leading strand, Okazaki fragments formed on lagging strand.
    • Central Dogma:
      • Transcription: RNA polymerase synthesizes mRNA from DNA in nucleus.
      • Processing: Eukaryotic mRNA processed to remove introns, addition of 5' cap and poly A tail before translation.
      • Translation: tRNA brings amino acids to mRNA codon, forming polypeptide chain using codon chart.
    • Gene regulation: Operons in prokaryotes, transcription factors and inhibitors in eukaryotes.
    • Biotechnology: Focus on sequencing.
Unit Seven: Natural Selection
  • Necessary Conditions for Natural Selection:
    • Genetic variation, struggle for survival, reproductive success.
    • Traits best adapted to the environment are favored.
  • Artificial Selection:
    • Human influence, as seen in domesticated plants and animals.
  • Evolution Concept:
    • Definition: Change in allele frequency over time.
    • Factors: Natural selection, mutation, small population size, non-random mating, gene flow.
  • Hardy-Weinberg Equilibrium:
    • Conditions for stability; shifts indicate evolutionary changes.
  • Evidence for Evolution:
    • Includes fossils, biogeography, homologous and vestigial structures, molecular comparisons.
  • Important Processes: Speciation, extinction; interpreting phylogenetic trees and cladograms.
  • Early Earth conditions favored organic molecules and the development of RNA.
Unit Eight: Ecology
  • Communication and Environmental Response:
    • Importance of responsiveness to environmental changes for fitness.
  • Energy Flow:
    • Trophic levels from autotrophs to heterotrophs; energy decreases at higher levels, affecting population sizes.
  • Population Growth Factors:
    • Resource limits, carrying capacity.
    • Review relevant equations: Simpson's Diversity Index, Exponential Growth, Logistic Growth.
  • Ecosystem Variation:
    • Variation among organisms enhances resilience to environmental changes.
    • Understand organism niches, such as keystone species or invasive species, and community dynamics.
  • Types of Biological Relationships:
    • Predation, competition, symbiosis.
  • Human Impact:
    • Ecosystem disruption, habitat modification, and extinction as negative consequences of human activity.
Recap of AP Biology Units
  • Units Covered:
    • 1. Chemistry of Life
    • 2. Cell Structure and Function
    • 3. Cellular Energetics
    • 4. Cell Communication and Cell Cycle
    • 5. Heredity
    • 6. Gene Expression and Regulation
    • 7. Natural Selection
    • 8. Ecology
  • Each unit has different weights on the AP exam. The triage method helps prioritize study focus: red first, yellow second, green skipped.
  • Additional resources linked in the description for further support.