9.4. Biochemical Reactions http://www.ck12.org
Cellular Respiration
Cellular respirationis the process in which the cells of living things break down glucose with oxygen to produce
carbon dioxide, water, and energy. The overall chemical equation for cellular respiration is:
C 6 H 12 O 6 +6O 2 →6CO 2 +6H 2 O+Heat and Chemical EnergyCellular respiration releases some of the energy in glucose as heat. It uses the rest of the energy to form many,
even smaller molecules. The smaller molecules contain just the right amount of energy to power chemical reactions
inside cells. You can look at cellular respiration in more detail at this URL: http://www.youtube.com/watch?v=J
yMfKP1D7OE (12:38).
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/5094Enzymes and Biochemical Reactions
Human body temperature must remain within a narrow range around 37°C (98.6°F). At this temperature, most
biochemical reactions would occur too slowly to keep us alive. That’s where enzymes come in. Enzymesare
biochemical catalysts. They speed up biochemical reactions, not only in humans but in virtually all living things.
Most enzymes are proteins. Two are described inFigure9.27.
Lesson Summary
- Biochemical reactions are chemical reactions that take place inside living things. Two of the most important
biochemical reactions are photosynthesis and cellular respiration. - Photosynthesis is the process in which plants and certain other organisms synthesize glucose from carbon
dioxide and water using light energy. Oxygen is also produced. - Cellular respiration is the process in which the cells of living things break down glucose with oxygen to
produce carbon dioxide, water, and energy. - Enzymes are biochemical catalysts that speed up biochemical reactions. Without enzymes, most chemical
reactions in living things would occur too slowly to keep organisms alive.
Lesson Review Questions
Recall
- What is photosynthesis? Write the overall chemical equation for this process.