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APhigh school

Biology Systems

A systems-level biology course exploring how cellular respiration, DNA replication, ecosystem energy flow, and immune response work as interconnected biological systems. Emphasizes process-level thinking and misconception-targeted diagnostics.

4units
4topics
60questions
~2hours

Course Units

Learning objectives

  • Describe the four stages of aerobic cellular respiration and identify where each occurs in the cell
  • Calculate the net ATP yield from each stage and the total yield per glucose molecule
  • Explain how the electron transport chain uses NADH and FADH2 to generate a proton gradient and drive ATP synthesis via chemiosmosis
  • Compare aerobic respiration with anaerobic fermentation in terms of inputs, outputs, and ATP efficiency
  • Explain how the body switches between aerobic and anaerobic pathways during exercise and why oxygen debt occurs

Topics in this unit

Learning objectives

  • Explain the semiconservative model of DNA replication and describe the evidence from the Meselson-Stahl experiment
  • Identify the roles of helicase, primase, DNA polymerase, ligase, topoisomerase, and SSBs at the replication fork
  • Compare leading and lagging strand synthesis, explaining why Okazaki fragments form on the lagging strand
  • Describe the three layers of replication fidelity and calculate how each reduces the error rate
  • Explain the consequences of telomere shortening during repeated DNA replication and its connection to cellular aging

Topics in this unit

Learning objectives

  • Trace the path of energy from sunlight through producers, consumers, and decomposers in an ecosystem
  • Apply the ten percent rule to calculate energy available at each trophic level
  • Distinguish between gross primary productivity (GPP) and net primary productivity (NPP)
  • Explain why energy flows one way through ecosystems while matter cycles
  • Compare energy flow in photosynthetic ecosystems with chemosynthetic ecosystems found at hydrothermal vents

Topics in this unit

Learning objectives

  • Compare and contrast innate and adaptive immunity in terms of speed, specificity, and memory
  • Explain how B cells produce antibodies and form memory cells to provide long-term immunity
  • Describe the roles of helper T cells and cytotoxic T cells in coordinating and executing immune responses
  • Explain how vaccines exploit immunological memory to prevent disease without causing infection
  • Explain how autoimmune diseases and allergic reactions result from immune system dysfunction and overactivation

Topics in this unit