Cellular_Respiration

Greetings and Agenda

  • Welcome Back: Introduction for students.

  • Agenda Topics:

    • ATP in Living Systems

    • Glycolysis

    • Citric Acid Cycle

    • Oxidative Phosphorylation

    • Overview of Cellular Respiration

Learning Objectives for Cellular Respiration

  • ATP Utilization: Understand how ATP serves as an energy source.

  • Glycolysis Outcomes: Explain the molecule production from glucose breakdown in glycolysis.

  • Location Knowledge: Identify where the citric acid cycle and oxidative phosphorylation occur within the cell.

  • Product Overview: Describe results from the citric acid cycle and oxidative phosphorylation.

  • Process Relationships: Connect glycolysis, citric acid cycle, and oxidative phosphorylation in terms of their inputs and outputs.

Energy Transformations in Living Systems

  • Producers: Plants transform energy.

  • Consumers: Animals utilize energy in various forms.

  • Decomposers: Fungi, bacteria, and worms break down organic material.

  • Energy Loss: Energy is often lost as heat during transformation.

Cellular Respiration vs. Breathing

  • Gas Exchange: Breathing involves the exchange of O2 and CO2.

  • Cellular Respiration: Involves the breakdown of food molecules in the presence of oxygen to harvest energy.

  • Relationship: Cells utilize O2 from breathing to break down fuel, resulting in CO2 production as a waste product.

Stages of Cellular Respiration

  1. Glycolysis:

    • Location: Cytosol

    • Function: Initiates cellular respiration.

  2. Pyruvate Oxidation and Citric Acid Cycle:

    • Location: Mitochondria

    • Function: Oxidizes pyruvate and further breaks down glucose.

  3. Oxidative Phosphorylation:

    • Location: Mitochondria

    • Function: Produces ATP via chemiosmosis and electron transport.

  • Chemiosmosis: Utilizing H+ ion gradients across membranes to generate ATP.

ATP in Living Systems

  • Energy Extraction: Energy from food is converted into ATP; the remainder is lost as heat.

Cellular Respiration and ATP Production

  • Exergonic Process: Cellular respiration releases energy while transforming glucose into ATP.

  • ATP Yield: Up to 32 ATP molecules can be produced from one glucose molecule.

  • Efficiency: Approximately 34% of glucose energy is harnessed as ATP; 66% is lost as heat, necessitating cooling mechanisms during intense activity.

ATP's Role in Cellular Work

  • ATP couples exergonic (energy-releasing) and endergonic (energy-requiring) reactions.

  • Structure of ATP: Contains adenine, ribose, and three phosphate groups.

  • Phosphorylation: ATP energizes other molecules by transferring a phosphate group.

Energy Transfer in ATP Cycle

  • Endergonic Process: Breakdown of glucose during cellular respiration.

  • Exergonic Process: Hydrolysis of ATP releases energy, which powers endergonic processes.

  • Energy Transfer Mechanism: Exergonic actions phosphorylate ADP to regenerate ATP, facilitating energy transfer through phosphorylation.

Glycolysis Overview

  • Reactants: Glucose and 2 ATP start the process.

  • Products: Results in 2 NADH, 4 ATP (net gain of 2 ATP), and 2 Pyruvate molecules.

The Citric Acid Cycle

  • Mechanism of Energy Capture: Electrons are extracted from fuel molecules and transferred to NAD+ to form NADH.

  • NADH Role: Shuttles electrons to the electron transport chain, releasing energy through multi-step reduction to O2.

  • Citric Acid Cycle Definition: A series of reactions that extract energy through oxidation of acetyl CoA derived from pyruvate.

Oxidative Phosphorylation

  • Electron Transfer Chain: H+ ions are pumped into the intermembrane space, creating a gradient.

  • ATP Synthase Function: H+ ions flow back into the mitochondrial matrix through ATP synthase, generating ATP from ADP and Pi.

  • Overall Reaction: Oxygen acts as the final electron acceptor in the chain, producing water as a by-product.