Objective: To investigate the effect of using different carbon source on the growth of yeast cells.

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NAME: FARAH NADZIRAH ROSLI

CLASS: ALM 7 M 13

Title: Using Different Carbon and Source for Growth

Objective: To investigate the effect of using different carbon source on the growth

of yeast cells.

Background summary:

Growth depends upon both the type of the nutrients available and their concentration. Cells are largely made up of the four elements: carbon, hydrogen, oxygen and nitrogen with smaller, but significant, quantities of phosphorus and sulphur. Accounting as they do for 90% of the cell's dry mass, all six elements are essential for growth. Hence, like all living organisms, microorganisms require an energy source, a carbon source and a range of nutrients for metabolic and cell growth.

Microorganisms are small, easily dispersed and quick to multiply given a suitable environment. They grow on a wide diversity of substrates making them ideal subjects for commercial application. The microorganisms need organic carbon source, such as carbohydrates, as most of them are heterotrophic. Carbohydrates act as a respiratory substrate of cells. Microorganisms also need a nitrogen source for synthesis of DNA, RNA, ATP, coenzymes and chlorophylls. Apart from that, each species has its own optimum conditions within which it grows best.

Respiration involves a series of metabolic pathway, which is a series of enzyme-controlled chemical reaction, where the product of one reaction becomes the substrate for the following reaction. It consist of two different type: aerobic respiration and anaerobic respiration. Aerobic respiration involves glycolysis, Krebs cycle and oxidative phosphorylation while anaerobic respiration only involves glycolysis. The ultimate purpose of respiration is to produce ATP, the free energy for cells.

Yeast only consumes carbohydrate in the form of simple sugars such as monosaccharide and disaccharides for respiration. Therefore, in this experiment, we will be investigating the ability of yeast to utilize different carbon sources as a substrate in anaerobic respiration. A range of different carbohydrates are used as carbon sources, which are glucose and sucrose, and relative rate of respiration will be determined by measuring the production of acid by the yeast cells: the faster the rate of respiration, the faster the rate of acid production.

Materials:

2 % sugar solutions of glucose and sucrose, 500 ml flask with cotton wool plugs, ammonium phosphate, ammonium sulphate, burette and stand, 0.1 M of sodium hydroxide, phenolphthalein indicator solution.
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Method:

. 200 ml of 2% of different sugar solutions are added to separate, labelled flask. One flask containing 200 ml of distilled water is included to act as a control.

2. 2 g dried yeast and 1 g of culture nutrients are added to each flask. The culture nutrients are a mixture of equal masses of ammonium phosphate and ammonium sulphate. The flask is swirled or the content is stirred thoroughly with a glass rod to ensure that the nutrients dissolved and that the yeast is resuspended.

3. Each flask is plugged with cotton ...

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