. Adventures with animals and plants. Biology. PROBLEM 2. How Cclls Keep Alive tion (burning) usually takes place. The paper unites with the oxygen which is present in the air. In uniting, it forms a variety of oxides and produces heat and light. It is true that the paper does not burn until you touch a lighted match to it; the match serves to heat the paper to its kindling temperature. This is gen- erally necessary for rapid oxidation. Slow oxidation occurs at lower temperatures. There is another difference between slow and rapid oxidation. In slow oxida- tion no light is produced. But heat i
. Adventures with animals and plants. Biology. PROBLEM 2. How Cclls Keep Alive tion (burning) usually takes place. The paper unites with the oxygen which is present in the air. In uniting, it forms a variety of oxides and produces heat and light. It is true that the paper does not burn until you touch a lighted match to it; the match serves to heat the paper to its kindling temperature. This is gen- erally necessary for rapid oxidation. Slow oxidation occurs at lower temperatures. There is another difference between slow and rapid oxidation. In slow oxida- tion no light is produced. But heat is always produced whenever oxidation takes place; the slower the oxidation, the less the heat. In fact the amount of heat may be so small that delicate instru- ments are needed to detect it. At this point, unless you have done these ex- periments before, you will find it profit- able to do Exercises 4, 5, and 6, Also try Exercise 7. Let us sum up what we have learned about oxidation: Oxygen must be pres- ent if oxidation is to take place; an oxide, or^compound of oxygen with another substance, is always formed; heat is re- leased; and if the oxidation is rapid, light is also produced. Oxidation occurs in all living cells. Some of the compounds in the proto- plasm, particularly carbohydrates and fats, unite with oxygen. Oxides are formed in the cell and heat is produced. Among these oxides is carbon dioxide. Can you devise an experiment to show that oxidation goes on somewhere in your body? Do Exercise 8. Ordinarily, in this oxidation within the cell no light is produced. Oxidation within the cell is of great importance. The whole proc- ess is also called cellular respiration. 119. Fig. 147 Tlois is using energy. Where does it come from? (public schools of evans- VILLE, INDIANA) Energy. What is energy? Energy can be defined as the ability to do work, that is, make something move. Energy makes work possible. You just read that when burning takes place heat and light are
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