Cell Structure and Function Overview

Sep 29, 2024

AP Biology Lecture: Cell Structure and Function

Overview

  • Continuation of Unit 2 on cell structure and function.
  • Focus on the structure and function of specific organelles: mitochondria and chloroplasts.
  • Emphasis on the theme "form meets function" – the structure of cell components supports their functions.

Recap of Previous Topics

  • Lysosomes
    • Function: Digest and break down macromolecules; involved in apoptosis.
    • Structure: Membrane-bound with enzymes.
  • Vacuoles
    • Function: Store molecules, waste products, and water (in plants for turgor pressure).
    • Structure: Membrane-bound.
  • Endoplasmic Reticulum (ER)
    • Structure: System of membranes with rough (ribosome-embedded) and smooth parts.
    • Function: Synthesizes proteins (rough ER), lipids (smooth ER), and provides mechanical support.

Mitochondria

  • Function
    • Conducts metabolic reactions, notably ATP synthesis.
    • Essential for aerobic cellular respiration.
  • Structure
    • Double membrane with outer and inner membranes.
    • Inner Membrane: Contains folds called cristae for increased surface area.
    • Compartments: Intermembrane space, mitochondrial matrix.
  • Processes
    • Glycolysis occurs outside mitochondria.
    • Krebs/Citric Acid Cycle occurs in the matrix.
    • Electron Transport Chain and ATP synthesis occur along the inner membrane via cytochromes.
  • Unique Features
    • Contains its own DNA and ribosomes.
    • Origin explained by endosymbiosis.

Chloroplasts

  • Function
    • Conducts photosynthesis.
  • Structure
    • Double membrane without folds.
    • Components: Thylakoids (poker chip-shaped), grana (stacks of thylakoids), stroma (fluid outside grana).
  • Processes
    • Light-dependent reactions occur in thylakoids/grana; involve chlorophyll and photosystems.
    • Light-independent (Calvin Cycle) reactions occur in the stroma.
  • Similarities to Mitochondria
    • Double membranes, compartmentalized reactions.
    • Likely evolved from independent organisms (endosymbiosis theory).

Next Steps

  • Upcoming topic will cover cell size, its significance, and mathematical calculations related to it.
    • Stay tuned for engaging with some math-related concepts.

Questions?

  • Encourage students to reach out with any queries or clarifications needed on today's topics.
  • Next focus: Cell size and related math. Get ready for some calculations!