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ZingPath: Cellular Energy: Respiration


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Cellular Energy: Respiration

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You will learn to the ways in which cells use the energy stored in sugar to produce the ATP that powers their chemical reactions. View each of the major pathways involved in ATP production, and then see how this compares to photosynthesis.

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Now You Know

After completing this tutorial, you will be able to complete the following:

  • Explain how cells obtain the energy they need.
  • Define glycolysis.
  • Briefly explain the reactions of glycolysis.

Everything You'll Have Covered

What is the chemical composition of glucose and pyruvate?

~ Glucose contains 6 carbon molecules, 12 hydrogen molecules, and 6 oxygen molecules. Pyruvate contains 3 carbon molecules, 3 hydrogen molecules, and 3 oxygen molecules.

Describe the steps that take place during the glycolysis reaction; from the introduction of the glucose molecule to the production of two pyruvate molecules.

~ At the beginning of the reaction, two ATPs (adenosine triphosphates) activate the breakdown of the glucose molecule. First, glucose is broken down into glucose-6-phosphate, then fructose-6-phosphate, and then fructose-1,6-diphosphate. This molecule is broken into two phospho-glyceraldehyde molecules that are converted to di-phosphoglyceric acid then to phosphoglyceric acid and finally into two pyruvate molecules.

What is produced during a glycolysis reaction other than two pyruvates?

~ During a glycolysis reaction, four ATPs, and two NADH +H+ (nicotinamide adenine dinucleotides) are produced. However, since two ATPs are required to initiate the reaction, the net amount of energy obtained from glycolysis is only two ATPs.

What happens to the two NADH +H+ molecules that are produced during glycolysis?

~ The two NADH +H+ that are produced during glycolysis pass into the mitochondria, are added into the electron transport system, and are then used in the production of ATP.

Describe the energy conversions that happen during glycolysis.

~ During glycolysis, the energy contained in glucose molecules is released. Some of this energy is used to produce ATP molecules that the cell can use. At the same time, NADH+ molecules are produced that can pass into the mitochondria, and they are added into the electron transport system. They are then used to produce more ATP molecules.

Tutorial Details

Approximate Time 2 Minutes
Pre-requisite Concepts Students should be able to know the terms ADP, ATP, and cell.
Course Biology
Type of Tutorial Animation
Key Vocabulary ADP, ATP, cell