Energy from Organic Compounds

Yeast gets its energy from organic compounds. It is affected by many factors, one of the factors include temperature as it affects the enzyme reaction, having a temperature thats low will mean the reaction speed will be very slow, as temperature increases the kinetic energy does as well so there is a greater rate in reactivity, the reaction is more likely to work best at its optimum temperature which is 40-45 degrees. Some yeast live in freezing conditions but many can also grow in normal environmental temperatures existing in different places.

Furthermore, PH can also affect respiration rate in yeast, species of yeast grow with a neutral PH or slightly acidic PH. Therefore, yeast extracts or foods derived from yeasts are more likely to be acidic. When it comes to culture medium, scientists use the same characteristic in organic acids as it is an effective culture medium. Acids and alkalis cause the structure of the enzyme to denature this is done by breaking mainly hydrogen and ionic bonds resulting in the face that the substrate can't fit the active site. Above and below the optimum pH of the enzyme activity indicates a reduction in the rate.

Moreover, Sugar and substrate concentrations as an effect on respiration rate suggesting the yeast concentration in the culture medium or in the environment will affect the rate of its growth. At low substrate concentrations, the rate of enzyme activity increases as the substrate increases. This occurs due to the higher frequency of collisions between the substrate molecules and the unoccupied active sites.

Minerals like potassium, magnesium etc.. encourage yeast growth. Oxygen, phosphorus and sulfur also encourage yeast growth.