What Is Yeast Respiration?

Lets first know what is yeast respiration? It is a single cell microbe which doesn’t contain any chlorophyll and is from the plant kingdom whereas respiration is glucose+oxygen=carbon dioxide+water+energy. Yeast respiration depends on various factors such as


Concentration of glucose

Amount of yeast

Oxygen level

Type of yeast

During exercise the cells respire and the body cannot take in oxygen for respiration and therefore the muscles need more energy as hardly any energy is made. This is done without the presence of oxygen. When people exercise they tend to breath heavy because a large amount of lactic acid accumulates in the muscles and to remove this lactic acid we breath heavy. Yeast is also used in making bread. Carbon dioxide get caught in the bubbles of the bread. The ethanol evaporates from the dough when it is baked and the dough releases glucose and it is taken by the yeast.
One can try a simple experiment to check yeast respiration.

    • Take 20cm3 of glucose and add some yeast in a test tube. Then add 2 drops of indicator solution and if you notice any change in the color it would mean that there is oxygen in the mixture.
    • Pour the liquid over the mixture as this would prevent the oxygen from getting into the mixture.
    • When you notice that the color doesn’t change which means that there is no oxygen. Take another tube and add some bicarbonate.
    • Leave this for 15 minutes and then observe it. The yeast if kept for some more time a different smell is produced. Ethanol gets accumulated in the mixture and this is called fermentation and the yeast turns sugar into ethanol


This experiment helps us understand how respiration takes place with yeast.

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