Respiration What is the purpose of respiration? Terms to Know - - PowerPoint PPT Presentation

Respiration

What is the purpose of respiration?

Terms to Know

• Reduced – gains electrons (RIG)
• Oxidized – loses electrons (OIL)
• H+ - hydrogen ion or proton
• NAD
• FAD
• Substrate Level Phosphorylation
• Oxidative Phosphorylation
• Chemiosmosis
• Proton-motive force

Mitochondria

Cellular Respiration Overview

Cellular Respiration Overview

• Occurs within the cytosol and mitochondria of

cells

• Yields up to 32 to 34 ATP molecules per glucose

molecule

• Three steps:
• 1. Glycolysis
• 2. Krebs Cycle
• 3. Electron Transport Chain

Cellular Respiration Equation

C6H12O6 + 6O2 6CO2 + 6H2O + ATP

• Redox Reaction: movement of electrons from
• ne molecule to another
• Electrons lose potential energy as they move,

and energy is released

Cellular Respiration Summary

Cellular Respiration Overview

First Step: Glycolysis

Substrate-Level Phosphorylation

First Step: Glycolysis

• Glucose is oxidized into two molecules of pyruvic

acid (or pyruvate)

• Occurs within the cytosol of cells
• 2 ATP molecules are produced as well as 2 NADH

molecules

• NAD+ is an electron “shuttle”

Second Step: Krebs Cycle

Second Step: Krebs Cycle

• Occurs within the mitochondrial matrix
• Pyruvic acid is first oxidized to produce CO2 and 2

additional ATP molecule resulting in a highly reactive compound called Acetyl-CoA

• Electron carrier molecules NADH and FADH2 are

produced – transfer electrons (energy) to the electron transport chain

Third Step: Electron Transport Chain

Third Step: Electron Transport Chain

• Occurs within the inner mitochondrial

membrane

• High energy electrons (transported by NADH

and FADH2 molecules) enter the electron transport chain and release energy as they pass from one carrier molecule to the next

Third Step Continued: Electron Transport Chain

• The energy released is used to combine inorganic

phosphate to ADP produce 26-28 additional ATP molecules (oxidative phosphorylation)

• Oxygen molecules serve as the final electron

acceptor due to its electronegativity

• Hydrogen ions (H+) combine with oxygen to

produce H2O (water)

Cellular Respiration Summary

Fermentation

• Begins with glycolysis
• Purpose of fermentation is to regenerate

NAD+ from NADH to drive glycolysis (no glycolysis = cell death)

• Two types: lactic acid fermentation and

alcoholic fermentation

Lactic Acid Fermentation

• Occurs in animals in times of oxygen debt (i.e.

strenuous exercise and some bacteria

Alcoholic Fermentation

• Occurs in bacteria and yeast