BiochemistryLesson 2 of 3 in the course Cellular Respiration

Glycolysis: Energy Investment, ATP Production, and Net Yield

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

Glycolysis is the first stage in the breakdown of glucose and a pathway shared by nearly all living organisms. This lesson introduces where glycolysis occurs, how glucose enters cells, and how the first five steps prepare glucose for energy extraction.

Glycolysis means the breakdown of glucose. It begins with one six-carbon glucose molecule and ultimately produces two three-carbon pyruvate molecules. The pathway takes place in the cytoplasm of both prokaryotic and eukaryotic cells. It does not use oxygen directly, so it is described as anaerobic.

All flashcards

What is glycolysis?
A cytoplasmic pathway that converts one glucose molecule into two pyruvate molecules without directly using oxygen.
How do GLUT proteins transport glucose?
They facilitate glucose movement across the plasma membrane by facilitated diffusion.
How does phosphorylation help retain glucose in a cell?
It adds a negative charge, making glucose-6-phosphate unable to cross the membrane or leave through GLUT transporters.
How is phosphofructokinase regulated?
It is more active when ADP is abundant and less active when ATP is abundant.
What is the net yield of glycolysis per glucose?
Two ATP, two NADH, and two pyruvate molecules.

Quiz questions

  1. Why is glycolysis described as anaerobic?Answer: It does not use oxygen directly.
  2. What happens to phosphofructokinase activity when ATP is abundant and ADP is low?Answer: Its activity decreases, slowing glycolysis.
  3. What does aldolase produce when it cleaves fructose-1,6-bisphosphate?Answer: Dihydroxyacetone phosphate and glyceraldehyde-3-phosphate.
  4. Why must NADH be oxidized back to NAD+ for glycolysis to continue?Answer: The pathway requires NAD+ to accept electrons during glyceraldehyde-3-phosphate oxidation.
  5. Why do mature mammalian red blood cells depend on glycolysis for ATP?Answer: They lack mitochondria and cannot carry out aerobic respiration.

Based on Biology 2e by Mary Ann Clark, Matthew Douglas, Jung Choi (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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