Chapter 8, Problem 30A

Summary Introduction

To define:

The given vocabulary term in a complete sentence.

Introduction:

Organisms obtain energy through a process called cellular respiration. This process occurs in two stages; glycolysis and aerobic respiration. Some cells can function for a short time when oxygen levels are low. Some prokaryotes are anaerobic organisms. In some cases, cells continue to produce energy through glycolysis.

Answer to Problem 30A

Fermentation- The anaerobic pathway that follows glycolysis when there is insufficient supply of oxygen is called fermentation.

Explanation of Solution

Fermentation occurs in cytoplasm and regenerates cell’s supply of NAD+ while producing a small amount of ATP. There are two types of fermentation:

Lactic acid fermentation- In this process, the enzymes convert the pyruvate made during glycolysis to lactic acid. Skeletal muscles produce lactic acid when the body cannot supply enough oxygen during strenuous exercise. Many microorganisms also produce lactic acid during the formation of cheese, yoghurt and sour cream.

Alcohol fermentation- This occurs in yeast and in some bacteria. In this process, pyruvate is converted to ethyl alcohol and carbon dioxide.