The Effect of Different Temperature on the Cell Respiration.

The effect of different temperature on the cell respiration.
Introduction：

Cell respiration is the controlled release of energy from organic compounds in cells to form ATP,and then release waste products. The process of cell respiration can take place in the presence or absence of oxygen. In either case,the first stage of cell respiration is glycolysis.The effect of temperature on cell respiration mainly depends on the effect of temperature on of enzyme activity.Generally speaking in a certain temperature range,as the temperature rises, the rate of cellular respiration will enhance, molecules have more motion and activity.On the other hand,as the temperature decreases, the rate of cellular respiration will weaken and molecules have less motion and activity.However, if the temperature is slightly higher than the optimum temperature, the activity of enzyme will start to decreases and the cell respiration will stop.As shown below.

From the figure above, we can observe point B is optimum temperature.On this occasion,cell respiration rate will be the highest.

Research question:
How will the different temperature affect cell respiration? In this experiment,we will have to measure the change of carbon dioxide released in the process of cell respiration under different temperatures (7℃,25℃,60℃). As carbon dioxide is the byproduct in the process of cell respiration,the more active the cell respiration is, the more carbon dioxide will be released.
Hypothesis:
The hypothesis is that when the temperature at 25℃, has the maximal reactivity of cell respiration rate. If we lower the temperature at 7℃ or raise it above 60 ℃ , the rate of cell respiration would slow down,because at the very low temperature(7℃) enzyme will be inactive and at a very high temperature (above 60 ℃ ), the enzyme would denature and the structure of it changes permanently.

VARIABLES
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Apparatus • Thermometer (range 0 ℃ to 100 ℃ ) • 3×plastic bag • 3 ×immaturate apples • laptop ,data cable • Marker pen • Freezer • Air condition • Muff heater • Watch • 3×Label paper • Carbon dioxide gas sensor

Risk assessment • Wear the scientific protective goggles all the time to protect your eyes from any harmful substances. • Tie up your hair if your hair is too long or it blocks your vision. • Wear a lab coat to prevent any harmful substances to have contact with your skin. • Always wear a pair of gloves when handling acidic solution and alkaline solution. • Wear a pair of comfortable and safety footwear in order to minimize the risk of slipping and falling. • Carry out the experiment in a bright, well lit, ventilated room. Ensure the room is clean with clean work surfaces to avoid any cross contamination.
Methods
1. Choose 3 immaturate apples which are same size,same variety and the best is pick at same time.
2. Put the 3 apples into plastic bag respectively and label the 3 sample apples with 7℃，25℃，60℃ respectively.
3. Place the 3 sample apples into different temperature environment( 7℃，25℃，60℃)which are control by freezer,air condition and muff heater.
4. Connect the carbon dioxide gas sensor and the data acquisition unit with the laptop.
5. Place the sample apples for 24 hours.Observe the change of the apples every 8 hours and record the data.
6. Connect the sample with the carbon dioxide gas sensor. Collect the volume of carbon dioxide being released in the respiration process in 24 hours. Collect the data per 8 hours.
7. Record the data and analyze it.
8. Write down the conclusion and evaluation
9. In order to get more reliable results, the whole experiment can be repeated 5 times to calculate the mean of the carbon dioxide produced.

Reference

http://epub.cnki.net/grid2008/docdown/pubdownload.aspx http://en.wikipedia.org/wiki/Cell_respiration http://wenku.baidu.com/view/a08aaa2f3169a4517723a3df.html
http://mall.cnki.net/magazine/Article/CAIZ201121179.htm