VH

Cellular Respiration Notes

Cellular Respiration

C2: Cellular Respiration Objectives

  • Explain how glucose is oxidized during glycolysis and the Krebs cycle to produce reducing power in the form of NADH and FADH.
  • Explain how chemiosmosis converts the reducing power of NADH and FADH to store chemical potential energy in the form of ATP.
  • Describe where in the mitochondrion these processes occur.
  • Distinguish between aerobic and anaerobic respiration and fermentation.
  • Summarize and explain the role of ATP in cellular metabolism.

Lesson 1: The Basics of Cellular Respiration

  • Key questions:
    • What is cellular respiration?
    • What is needed for cellular respiration?
    • Where does it occur?

Cell Structure Review

  • Cell structures include:
    • Vacuole
    • Cell membrane
    • Endoplasmic reticulum (rough)
    • Ribosomes
    • Nucleus
    • Nuclear envelope
    • Nucleolus
    • Cytoplasm
    • Mitochondria
    • Nuclear pore
  • Mitochondria are responsible for producing energy for the cell.

Releasing Stored Energy

  • Chemical energy in molecules like glucose is stored in the bonds.
  • Breaking these bonds releases energy.
  • Cellular respiration: mitochondria break down carbohydrates (and fats) to generate adenosine triphosphate (ATP) molecules.

Cellular Activity

  • ATP provides energy for cell functions, including:
    • Active transport
    • Chromosomal movement
    • Cell movement (via cilia and flagella)
    • Muscle contraction
    • Synthesis of macromolecules

How ATP Works

  • ATP is a high energy molecule due to the negative charges on the phosphate groups.
  • When the third phosphate group breaks, energy is released: ATP \rightarrow ADP + P

ATP as Energy Currency

  • The body converts food energy into small units of chemical energy, ATP.
  • ATP participates in enzyme-controlled chemical reactions to do cell work.
  • ATP is the body's energy 'currency'.
  • ATP \rightarrow ADP + P + Energy

Mitochondria

  • Matrix: fluid-filled space of the inner membrane; contains enzymes for breaking down carbohydrates and other high energy molecules.
  • Cristae: folds within the inner membrane that provide a large surface area for ATP production.

Metabolic Pathways

  • Photosynthesis:
    • 6CO2 + 6H2O + energy (light) \rightarrow C6H{12}O6 + 6O2
  • Cellular Respiration:
    • C6H{12}O6 (s) + 6 O2 (g) \rightarrow 6 CO2 (g) + 6 H2O (l) + energy (heat)

Oxidation & Reduction

  • Oxidation: when an atom or molecule loses an electron.
  • Reduction: when an atom or molecule gains an electron.
  • Whenever one molecule is oxidized, another must be reduced.
  • Mnemonic: "OIL RIG" (Oxidation Is Loss, Reduction Is Gain) or "LEO GER" (Lose Electrons Oxidation, Gain Electrons Reduction).

Reducing Power

  • All compounds and atoms have more energy in their reduced form (e.g., glucose).
  • Reduced molecules with large amounts of energy available have reducing power.

Cellular Respiration Details

  • Glucose is oxidized, and oxygen is reduced.
  • Glucose breakdown is an oxidation-reduction reaction.
  • Breakdown of one glucose results in 36 to 38 ATP molecules through a series of reactions and cycles.

Overview: Cellular Respiration

  • With oxygen = aerobic respiration
  • Without oxygen = anaerobic respiration
  • Cellular respiration takes place in the mitochondria.
  • This process uses glucose from autotrophs to synthesize ATP.
  • Carbon dioxide is a by-product of cellular respiration, which can take place either with or without oxygen.

Aerobic Cellular Respiration - Main Steps

  1. Glycolysis
  2. Kreb's Cycle
  3. Electron Transport Chain