Question

The end product of anaerobic respiration in plants is-
A) Pyruvic acid
B) Malic acid
C) Ethyl alcohol
D) Methyl alcohol

Answer 1

Hint: Anaerobic respiration occurs without oxygen.
Anaerobic respiration are two types-
1) Alcohol fermentation
2) Acid fermentation

Complete Answer:
A) Pyruvic acid: The Chemical formula Pyruvic acid is $CH_{3}COCOOH$. Pyruvic acid produces energy through Krebs cycle. Krebs Cycle is the mitochondrial part of aerobic respiration that takes place after Glycolysis(cytoplasmic part).so Pyruvic acid is the end product of Glycolysis.

B) Malic acid: The chemical formula of malic acid is $C_4H_4O_4$. Malic acid is formed through a series of chemical reactions in Krebs cycle and it involves the oxidative metabolism of acetyl units as the premium source of cellular energy. So Malic acid is a product of Krebs cycle or aerobic respiration.

C) Ethyl alcohol: The chemical formula of ethyl alcohol is $CH_3CH_2OH$. Another name of ethyl alcohol is ethanol. Ethanol is a product of anaerobic respiration. In anaerobic respiration glucose from pyruvate through glycolysis and then pyruvate form either ethanol or lactate through $NAD^+$ regeneration. If ethanol is the final product of anaerobic respiration then it is called alcohol fermentation. And if lactate or lactic acid is the final product then the process is called lactic acid fermentation.

D) Methyl alcohol: Biologically methanol is an aerobic respiration found in bacteria in soil ecosystems.

Note:
1. Anaerobic respiration takes place in muscle and produces lactic acid as waste byproduct.
2. Anaerobic cells use substances such as sulfate, nitrate, sulfur, and fumarate to drive their cellular respiration.