CLASS 7 SIMPLE

Midterm 1 Update

  • Blueprint of life and bacterial genetics moved to Midterm 2.

Class 7 Learning Outcomes

  • Define metabolism, catabolism, and anabolism.
  • Describe components of metabolic pathways (enzymes, ATP, electron carriers).
  • Explain ATP production methods: substrate-level phosphorylation and oxidative phosphorylation.
  • Discuss glucose catabolism: glycolysis, TCA cycle, electron transport chain, fermentation.

Metabolism Overview

  • Metabolism: sum of all chemical reactions.
    • Anabolic reactions: require energy to build molecules.
    • Catabolic reactions: release energy by breaking down molecules.

ATP Function

  • ATP: energy currency, releases energy when hydrolyzed to ADP + Pi.
  • Synthesized from ADP using solar energy or oxidative processes.

Redox Reactions

  • Oxidation: loss of electrons; Reduction: gain of electrons.

Electron Carrier: NAD+

  • NAD+ removes electrons and protons, oxidizing substrates.
  • Reaction: NAD+ + 2e- + 2H+ → NADH + H+.

Collision Theory

  • Chemical reactions occur when molecules collide, requiring activation energy.
  • Increasing temperature or pressure, or using enzymes can accelerate reactions.

Enzymes

  • Catalysts that speed up reactions by lowering activation energy.
  • Act on specific substrates, increasing reaction rate dramatically.

Carbohydrate Catabolism

  • Primarily involves glucose, with two main pathways: cellular respiration and fermentation.

Phosphorylation Methods

  1. Substrate-level phosphorylation: phosphate transfer from substrate to ADP.
  2. Oxidative phosphorylation: ATP made via the electron transport chain using O2.

Cellular Respiration Stages

  1. Glycolysis: glucose → 2 pyruvate, net gain of 2 ATP and 2 NADH.
  2. TCA Cycle: produces 2 ATP, 8 NADH, CO2 from pyruvate breakdown.
  3. Electron Transport Chain: generates 2-3 ATP per NADH, final electron acceptor is O2.

Fermentation

  • Starts with glycolysis, no TCA cycle or electron transport chain, yields 2 ATP/glucose.
  • Types include lactic acid fermentation and alcohol fermentation.

Food Catabolism

  • Breakdown of carbohydrates, lipids, and proteins to generate intermediates for metabolic pathways.

Anabolism

  • Synthesis of amino acids, lipids, nucleotides from precursor metabolites derived from glycolysis and TCA cycle.

Next Class

  • Continuation of metabolic pathways; Midterm 1 on October 14th.