Question

In muscles, anaerobic conditions change pyruvic acid to

• A. $C_2{H}_{5}OH$
• B. $C_3{H}_4{O}_3$
• C. $C_3{H}_6{O}_3$
• D. $C_2{H}_{4}O$

Answer 1

Answer: (C)

$C_3{H}_6{O}_3$

• C${}_3$H${}_6$O${}_3$ is the chemical formula for lactic acid. In animals cells like muscle cells, anaerobic conditions result in lactic acid fermentation as shown below:
  

Pyruvic acid + NADH $\to$ Lactic acid + NAD${}^{+}$

• C${}_2$H${}_5$OH (ethanol) is produced by alcohol fermentation in yeast.
  
• C${}_3$H${}_4$O${}_3$ and C${}_2$H${}_4$O are not the respiratory product.