Anaerobic Respiration

Anaerobic Respiration

Anaerobic Respiration

• aka fermentation

• used by organisms that lack the enzymes necessary to utilize O2

• other organisms are aerobic but revert to anaerobic respiration if O2 is not available

Anaerobic respiration takes place in the cytoplasm of a cell.

The pathway begins with Glycolysis

• "splitting sugar"

• involves a series of 10 chemical reactions which break glucose (6-carbon sugar) into 2 molecules of pyruvate (3-carbon sugar)

ATP Production

• glucose is a very stable molecule 

• glycolysis requires an investment of 2 ATP molecules to get the process started

For each molecule of glucose:

• 2 ATP molecules are invested to start glycolysis

• 4 ATP molecules are produced

• Net gain = 2 ATP molecules

The overall equation for glycolysis

• 2 ATP + C6H12O6 →  2 pyruvate + 4 ATP

• 
  

• 
  

IF NO OXYGEN IS PRESENT

• Cell respiration stops with glycolysis

• 2 ATP + C6H12O6 →  2 pyruvate + 4 ATP

Some bacteria convert pyruvate to lactic acid

• used in dairy industry to manufacture cheese, butter, sour cream and yogurt (produces sharp or sour taste)

• 
  

• also used to produce soy sauce from soybeans, to pickle cucumbers, and to produce sausage, pepperoni, and salami

  
  

Animal cells utilize fermentation if O2 is not available

• Lactic acid is produced

• associated with muscle soreness and fatigue

Yeast (a fungus) can do aerobic or anaerobic respiration

When no oxygen is present, yeast converts pyruvate to alcohol and CO2

• used by brewing and baking industries

Multiple Choice

What are possible products of certain types of anaerobic respiration?

• water and oxygen

• pyruvic acid and glycerol

• nitrogen gas and ammonia

• alcohol and carbon dioxide

Multiple Choice

Which term best defines a bacteria that can survive without oxygen?

• aerobic

• anaerobic

• heterotrophic

• autotrophic

Multiple Choice

The formation of lactic acid in human muscle cells is most closely associated with

• muscle fatigue

• protein synthesis

• an increase in alcohol consumption

• an increase in glucose production

Multiple Choice

Which intermediate substance is produced in both alcohol and lactic acid fermentation?

• oxygen

• pyruvate

• nitrogen

• starch