How much slower would hydrogen peroxide likely be decomposed if catalase was not available in cells?

It will take 1,000,000 times slower for Hydrogen Peroxide to decompose

Hydrogen peroxide is a toxic compound that usually destroys cell membrane. Also, it is a byproduct of metabolism that must be broken down quickly because it can cause damage to the cells. Moreover, catalase is an enzyme that is found in almost all the living organism and function by catalysing the decomposition of hydrogen peroxide into water and oxygen. However, the decomposition of hydrogen peroxide is very slow and cannot sustain human life in the absence of catalase.

Explanation:

Hydrogen peroxide is a harmful chemical which is broken down into oxygen and water by the catalase enzyme. The oxygen gas is released in to the air for next two minutes till reaches a steady rate and hence decrease further in an hour.  

The speed with which a catalase decompose hydrogen peroxide is times per second

In absence of catalase,  H2O2 will be decomposed at a rate slower by times

the generally accepted parts of modern cell theory include: all known living things are made up of one or more cells. all living cells arise from pre-existing cells by division. the cell is the fundamental unit of structure and function in all living organisms.