Rate of Respiration in Yeast Essay

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Rate of Respiration in Yeast

Aim: I am going to investigate the rate of respiration of yeast cells in the presence of two different sugar solutions: glucose, sucrose. I will examine the two solutions seeing which one makes the yeast respire faster. I will be able to tell which sugar solution is faster at making the yeast respire by counting the number of bubbles passed through 20cm of water after the yeast and glucose solutions have been mixed.

Prediction: I predict that the glucose solution will provide the yeast with a better medium by which it will produce a faster rate of respiration. This is because glucose is the simplest type of carbohydrate (monosaccharide). However sucrose is a
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Whereas the large molecule food (Sucrose) will take longer to break down because of its large molecules, this will waste the energy of the yeast as it has to break down the large molecules into smaller molecules before it can use them.

This means that the sucrose is not as efficient as the glucose at providing the yeast with a better medium by which it will produce a faster rate of respiration.

Theory: Yeast is a single celled fungus. It feeds saprophytically (secreting enzymes from cells) the enzymes digest the food on which the yeast is living. The enzymes digest the food the yeast is living on (normally sugars such as Glucose and Sucrose) breaking down the large molecules into smaller ones. It takes longer to break down the large molecules making them less efficient than the smaller molecules. This means that the yeast does not need to do any work when provided with small molecule foods such as glucose. The small molecule foods allow the yeast to respire easily.

The glucose should allow the yeast to respire more because it is already a small molecule sugar whereas the sucrose is a large molecule sugar this will mean that the yeast can use the glucose straight away without breaking it down, whereas with the sucrose it has to break it down into a simple sugar before it can use it this will take time
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