BIO 181 Lecture 4.4

Lecture 4.4: Glycolysis


The average cell contains about 2 billion ATP molecules. At rest, it “burns” (oxidizes) about 100 million per second. That gives it a reserve of about 20 seconds before the ATP is used up completely. If it runs out of ATP, as we saw in an earlier lecture, it loses control of its osmotic balance, and it will invariably swell and burst. So, something has to regenerate this ATP at the same rate it is used–viz., 100 million per second. These facts place energy metabolism–primarily metabolism revolving around ATP–at the heart of the cell’s metabolic system. ATP is regenerated by extracting energy from organic molecules. The beginning of the process that does this is glycolysis, so we start our detailed study of metabolism here.


  1. Review Section 9.1 of the textbook.
  2. Read Section 9.2 of the textbook.
  3. Download Lecture 4.4 slides.
  4. Do one of the following:
    1. In-person section: Attend Lecture 4.1.
    2. Online section: Watch the following videos:
      1. Video 4.4.1, Introduction to Energy Metabolism.
      2. Video 4.4.2, Glycolysis Details.
  5. Complete the questions on Study Guide 4.4.


After completing the activities, log into Canvas, launch BIO 181 and complete Lecture 4.4 Quiz.

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