BiochemistryLesson 5 of 5 in the course Mitochondria and cellular respiration

Glycolysis: Reactions, Regulation, and Metabolic Fates

5 flashcards · 5 quiz questions · 5 match pairs · 4 fill-in sentences · English

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Summary

Glycolysis is a central pathway for extracting usable energy from glucose. This lesson introduces its location, overall purpose, major forms, and the experiments that established our understanding of it.

Glycolysis is a sequence of ten enzyme-catalyzed reactions that converts one six-carbon glucose molecule into two three-carbon pyruvate molecules. In most organisms, these reactions take place in the cell's cytosol, the liquid portion of the cell.

All flashcards

What is glycolysis?
A ten-reaction pathway that converts one glucose molecule into two pyruvate molecules while capturing energy in ATP and NADH.
Why does phosphorylation trap glucose-derived intermediates inside cells?
Phosphorylation gives them a charge, so they do not readily cross the cell membrane.
What is substrate-level phosphorylation?
Direct transfer of a phosphate group from a metabolic intermediate to ADP to form ATP.
Why must cells regenerate NAD+ for glycolysis to continue?
NAD+ accepts electrons during glyceraldehyde 3-phosphate oxidation; without its regeneration, that reaction stops.
What is the Warburg effect?
High rates of glucose uptake and glycolysis in many cancer cells, even when oxygen is available.

Quiz questions

  1. What inhibits most cells' hexokinase when its concentration rises?Answer: Glucose 6-phosphate
  2. What does phosphoglycerate kinase do during glycolysis?Answer: Transfers phosphate from 1,3-bisphosphoglycerate to ADP.
  3. How does arsenate reduce ATP yield during glycolysis?Answer: It substitutes for phosphate, bypassing ATP formation at the phosphoglycerate kinase step.
  4. During fasting, what does glucagon signaling do to liver pyruvate kinase?Answer: Promotes its phosphorylation and inhibition.
  5. In aerobic eukaryotic cells, what happens to pyruvate as it enters mitochondrial metabolism?Answer: It is converted to acetyl-CoA, releasing carbon dioxide and producing NADH.

Based on the Wikipedia article Glycolysis, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.

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