Ib Biology Enzymes Ia

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Biology Enzymes IA
Design
Introduction:
Enzymes are globular proteins, they are responsible for most of the chemical activities of a living organism. They act as catalysts, substances that affects the reaction of other substances without being destroyed or altered during the process. They are extremely efficient in the body system of living organisms, one enzyme may catalyse over a thousand chemical reactions every second. But there are certain conditions that need to be fulfilled in order for the enzymes to work. Temperature of the environment must be correct for each enzyme because different enzymes will have different temperature ranges in which they can live. pH levels in the environment must also be correct because if the environment around the enzyme is too basic or acidic, the enzyme will quickly denature. Hydrogen peroxide (H2O2) is naturally formed in living organisms, however it is very harmful and is broken down immediately by several enzymes including catalase. This enzyme catalyses the breakdown of hydrogen peroxide to water and oxygen. Persons with acatalasemia (a hereditary condition) have extremely low catalase activity and, although present worldwide, it is more commonly found in Koreans. Hydrogen Peroxide is usually used as a topical disinfectant in wounds and the bubbling that is seen in the experiment is due to the oxygen gas released from the tested substance. Because of this, any cell that uses oxygen or lives in the presence of oxygen must have a way to get rid of the peroxide. One of these ways is to make catalase.

Research Question:
“In what manner will the product of the enzymatic reaction be released from the different substances placed with the test tube?” “Different food items will produce different amount of bubbles when tested with the hydrogen peroxide”

Variables:
Table of Variables
Independent Variable| Dependent Variable| Controlled Variable | Uncontrolled Variables| Different types of vegetables and fruits used for catalase testing| Amount of bubbles produced in the reaction| * Amount of hydrogen peroxide used to test each of the substances * Quantity of each substance * pH of the hydrogen peroxide| Temperature of the room |

Table of Controlled Variables
Variables | Method of Control |
Amount of hydrogen peroxide used to test each of the substances| Measured carefully with a measuring cylinder | Quantity of each substance| Each vegetables and fruit (with the exception of the Chinese cabbage) is cut to a block shape of 5×1×1cm dimension| pH of the hydrogen peroxide| Percentage concentration of hydrogen peroxide listed on the bottle | Apparatus List:

* Test tube rack
* Cutting knife
* Cutting board
* Stirring rod
* 5 test tubes
* 300ml glass beaker
* Pipette dropper
* 250 ml hydrogen peroxide of 3% concentration
* Stopwatch
* 1 red apple
* 1 carrot
* 3 branches of Chinese cabbage
* 1 potato
* 1 onion
Method
Set up the cutting board and place the cutting knife carefully, place the all 5 test tubes on the test tube rack. Place a designated substance on the cutting board (any of the listed fruit/vegetables above) for the purpose of this method write-up we will use the red apple. Use the cutting knife to cut the piece of apple into halves, after that use the knife to cut 5 pieces of the red apples into 5×1×1cm of volume. Do the same for the carrot, potato and onions. For the Chinese cabbage rip out bits of leaves from the plant and roll them up into a cylinder-like shape that’s approximately a volume of 5×1×1cm. At this point there should be 5 pieces (each) of red apples, carrots, potatoes and onions of a volume of 5×1×1cm + 5 rolled up pieces of Chinese cabbage. Place all these materials on the cutting board. Place all 5 of the red apples into the test tubes (1 piece for each test tube). Pour 250 ml hydrogen peroxide of 3% concentration into the 300 ml glass beaker. At this...
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