Which of the following explains the conservation of mass during cellular respiration?

the total number of atoms when carbon dioxide and oxygen react stays the same when glucose and water are produced.
the total number of atoms when water and oxygen react stays the same when glucose and water are produced.
the total number of atoms when carbon dioxide and water react stays the same when glucose and oxygen are produced.
the total number of atoms when glucose and oxygen react stays the same when carbon dioxide and water are produced.

The total number of atoms when glucose and oxygen reacts stays the same when carbondioxide and water are produced.

Explanation:

Chemical reaction:

C₆H₁₂O₆  +  6O₂  →  6CO₂ + 6H₂O

We can see that the number of atoms of each element remain same on both side of reaction so law of conservation of mass is followed by this reaction. Six number of carbon atoms twelve number of hydrogen atoms and eighteen number of oxygen atoms are present on both side.

There are two types of respiration:

1.Aerobic respiration  

2.Anaerobic respiration

Aerobic respiration

It is the breakdown of glucose molecule in the presence of oxygen to yield large amount of energy. Water and carbon dioxide are also produced as a byproduct.

Glucose + oxygen → carbon dioxide + water + 38ATP

Anaerobic Respiration

It is the breakdown of glucose molecule in the absence of oxygen and produce small amount of energy. Alcohol or lactic acid and carbon dioxide are also produced as byproducts.  

Glucose→ lactic acid/alcohol + 2ATP + carbon dioxide

This process use respiratory electron transport chain as electron acceptor instead of oxygen. It is mostly occur in prokaryotes. Its main advantage is that it produce energy (ATP) very quickly as compared to aerobic respiration.  

level 4 to level 2 : ))