How Does Green Light Affect Yeast

Aim:

To see which type of lighting shatters yeast cells at a faster rate

Hypothesis:

The brightly coloured lights will affect the yeast cells at a faster rate. This is because brightly coloured lights make its strength weaker and darker lights maintain its strength.

Background research:

Yeast

“Defined as a chemoorganotrophs, which is an organism that requires an organic source of carbon and metabolic energy.” (Medical Dictionary, 2012)

Several experiments have been conducted on how light affects yeast. Most results have been clearly presented the same. Tennessee State University studied changes in yeast respiration in the presence of blue and green light, find that light can be used to control short period respiratory oscillations in

Often this experiment is positioned in a dark room, so light does not separate the cell membranes and shatter them. Therefore different colours of light destroy the cells at different rates. “A cell is referred to a thin layer of tissue that covers a surface, divides a space, line a cavity or an organ. A cell membrane allows certain substances to pass through enclosing the cytoplasm of a cell.” (Medical Dictionary, 2012)

Yeast is extremely sensitised. Yeast that comes in contact with too hot or too cold water is fatal to the yeast. Water that is between 130-140˚F is lethal to yeast. For activation of dry yeast water should be between 105˚c-110 degrees Celsius for proofing. 95 degrees Celsius is the recommended temperature according to Cookistry for yeast to

Retrieve yeast and stir into corresponding bowl of water.

3. Time how long till yeast mixture bubbles. For undamaged yeast, should take about ten minutes. Take a picture at ten minutes, fifteen minutes and twenty minutes.

4. Repeat step three for all yeast samples.

5. Analyse the data.

Variables:

Variable Type of Variable How is it changed, measured or kept the same

Type of Light Independent Using three types of light bulbs (one red, blue and green) to active the yeast

Time taken for the yeast mixture to bubble Dependent Time with an electronic timer how long each mixture takes to bubble.

Amount of water Controlled Measured in a measuring cup, keeping the same amount of liquid each time.

Air temperature Controlled The same air temperature within the room. Checked with two different thermometers.

Amount of yeast Controlled Measured in grams. Checked with a scale.

Type of cardboard box Controlled Three boxes were the same type and size.

Type of metal bowl Controlled Five metal bowls same type and size.

Risk assessment:

Hazards that can