Lactic Acid Fermentation
Detailed mechanism of lactic acid fermentation, including the organisms involved and the production of lactic acid.
What is Lactic Acid Fermentation?
An anaerobic metabolic process that converts sugar to acids, gases, or alcohol. It occurs in yeast and bacteria, and also in oxygen-starved muscle cells, as a means of producing ATP with a closed electron transport chain.
Key formula / rule: Lactic Acid Fermentation Reaction
Key points
- Explain the steps of lactic acid fermentation.
- Identify the conditions under which it occurs.
- Describe its significance in ATP production and NAD+ regeneration.
- Name organisms that perform lactic acid fermentation.
Common exam trap
Confusing lactic acid fermentation with alcoholic fermentation.
Definitions
- Term
Fermentation
- Meaning
An anaerobic metabolic process that converts sugar to acids, gases, or alcohol. It occurs in yeast and bacteria, and also in oxygen-starved muscle cells, as a means of producing ATP with a closed electron transport chain.
- Term
Lactate Dehydrogenase (LDH)
- Meaning
An enzyme that catalyzes the conversion of pyruvate to lactate, using NADH as a reducing agent and producing NAD+.
- Term
NAD+ (Nicotinamide Adenine Dinucleotide)
- Meaning
A coenzyme essential for many metabolic reactions, acting as an electron acceptor. It is reduced to NADH when it accepts electrons.
Learning objectives
Explain the steps of lactic acid fermentation.
Identify the conditions under which it occurs.
Describe its significance in ATP production and NAD+ regeneration.
Name organisms that perform lactic acid fermentation.
Formulae
- Name
Lactic Acid Fermentation Reaction
- Note
This reaction is catalyzed by lactate dehydrogenase and regenerates NAD⁺.
- Expression
Pyruvate + NADH + H⁺ ⇌ Lactate + NAD⁺ + H₂O
Prerequisites
Glycolysis
Cellular Respiration (basic understanding)
Enzymes and Coenzymes (NAD+/NADH)
Common mistakes
Confusing lactic acid fermentation with alcoholic fermentation.
Forgetting that NAD+ regeneration is the primary purpose.
Assuming it produces additional ATP beyond glycolysis.
Keywords
Lactic acid fermentation
Anaerobic respiration
Pyruvate
Lactate
NAD+
NADH
Lactate dehydrogenase
Muscle fatigue
Lactobacillus
Practice preview
What is the net gain of ATP molecules per molecule of glucose during lactic acid fermentation?…
easy
In lactic acid fermentation, pyruvate is converted to lactate. What is the role of this conversion?…
easy
Which enzyme catalyzes the conversion of pyruvate to lactate during lactic acid fermentation?…
medium