Different amounts of glucose affect on Cell Respiration (yeast lab)

Different amounts of glucose affect on Cell Respiration

Abstract:

In this lab, we tested to see what would happen with different substances with different amounts of glucose and their affect on cell respiration. In the control, for the carbohydrate, we used sugar. The different variables we used were honey, flour, and potato starch. We suspected that since honey and sugar have more glucose, the amount of carbon dioxide produced would be higher.

Introduction:

Cell respiration is a process that produces ATP (energy.) In cell respiration, the cells use oxygen to break down glucose, or sugar, and create ATP. Without oxygen, cell respiration cannot occur. There are three main steps to cell respiration: glycolysis, the Krebs cycle, and oxidative phosphorylation. Cell respiration takes place in the mitochondria. In glycolysis, the 6-carbon sugar is broken down into 2 molecules of a 3-carbon molecule called pyruvate. In this step, 2 ATP molecules and 2 NADH molecules are gained. Then the pyruvate is transported into the mitochondria and loses carbon dioxide to form acetyl-CoA. In the Krebs cycle, acetyl-CoA is oxidized to carbon dioxide and a chemical energy is released and captured in the forms of NADH, FADH2, and ATP. Then oxidative phosphorylation and chemiosmosis is the next step. The electron transport chain in the mitochondria allows the release of chemical energy stored in reduced NAD+ and reduced FAD. Then the energy released is captured in the form of ATP. The electron transport chain is made up of proteins and other molecules in the inner mitochondrial membrane. Electron carriers donate electrons to the electron transport chain, which powers ATP synthesis from oxidative phosphorylation. Since yeast is a fungus, it also under-goes cell respiration. In our yeast lab, we have a control made up of 1g of carbohydrates (sugar), 35 mL of warm water, 1g of salt, and 1g of yeast. If we change the different carbohydrates and make those our variables, how will it affect the cell respiration of the yeast? Does the amount of glucose in them affect cell respiration? In our lab we used three variables instead of sugar. We used honey, flour, and potato starch. I hypothesize that the control and the honey will produce more carbon dioxide than the flour and the potato starch because they have more glucose.

 Materials:

-Test tubes attached to syringes

- Beakers

-Sugar

-Honey

-Flour

-Potato starch

- Water

- Salt

- Yeast

- Weighing scale

Procedure:

To keep the experiment accurate, we must make the control, the one with the honey, the one with the flour, and the one with the potato starch at the same time. To make the control you need 1g of sugar, 35mL of warm water, 1g of salt, and 1g of yeast. Once you have all the ingredients you have to put them into the test tube and shake. Use the same materials for the others except change the carbohydrate. So instead of 1g of sugar, use 1g of honey, 1g of flour, and 1g of potato starch. Once the substances are in the test tubes, push the syringe down to see the starting point of the carbon dioxide. After 5 minutes, 7 minutes, 8 minutes, 9 minutes, and 10 minutes push the syringe and see the new level of carbon dioxide.

Results:

As expected the control and the honey produced the most carbon dioxide. The baseline for the control is 2 mL, 5 minutes was 2 mL, 7 minutes was 3 mL, 8 minutes was 5.3 mL, 9 minutes was 7 mL, and 10 minutes was 8 mL. The baseline for the honey was 1.9 ml, 5 minutes was 3 ml, 7 minutes was 4.5 ml, 8 minutes was 5.3 ml, 9 minutes was 6.2 ml, and 10 minutes was 7.6 ml. The baseline for the flour was 2 ml, 5 minutes was 2 ml, 7 minutes was 2 ml, 8 minutes was 2 ml, 9 minutes was 2 ml, and 10 minutes was 2 ml. the baseline for potato starch was 1.6 ml, 5 minutes was 2 ml, and since the cap of the test tube was not properly sealed, we could not get any more data.

Conclusion:

Sugar and honey are both disaccharides and both contain a lot of glucose, and therefore they both produced a lot of carbon dioxide due to cell respiration. Flour is a starch and a polysaccharide so it has less glucose than the honey and the sugar. If we had timed the flour longer, then we would see a gradual rise in the level of carbon dioxide. Potato starch is also a polysaccharide and contains less glucose, and if there were no errors, and if we had more time, we would see a gradual rise in the level of carbon dioxide as well.