How does yhe type of food source affect the rate of cellular respiration in yeast?

During cellular respiration large food molecules (glucose, sucrose) are broken down into small molecules with the release of energy. Just like all other organisms, the process of cellular respiration is vital for the survival of yeast.

The nature of food is an important factor that affects the rate of cellular respiration in microorganism-yeast.

Reason:

This is because small food molecules are quickly broken down while large molecule like sucrose takes longer time. This makes large molecules less efficient source of energy for yeast as compared to small molecules.

Food sources of yeast:

Yeast can use different sugar and non-sugar based molecules as source of energy such as:

Glucose Lactose Sucrose

Glucose is a simplest sugar molecule and yeast do not needs to do much work for its breakdown. Unlike other sugars, glucose also enters in glycolysis directly while large sugars have to undergo hydrolysis before glycolysis. This means that glucose is more efficient than large sugars such as sucrose in meeting energy requirement and providing faster respiration rate.

Experimental evidences:

In experimentation, yeast was provided with different food sources and rate of respiration was determined by measuring the CO2 produced during respiration.

The results of the studies are as:

5% Glucose produced a respiration rate 11.29 ppm/s 5% Sucrose produced a respiration rate 14.14 ppm/s 5% Lactose produced a respiration rate 4.59 ppm/s

The experimental results also support the fact that the rate of cellular respiration is greatly dependent upon the food source.