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16: Sugar Metabolism

Students trace glucose through glycolysis to pyruvate, calculate net ATP and NADH yield, explain how fructose and galactose enter the pathway, describe NAD+ regeneration through fermentation, identify regulatory control points responsive to energy demand and hormonal signals, and contrast gluconeogenesis bypass reactions with irreversible glycolytic steps including reciprocal regulation between the two pathways.

Matching Cellular Respiration Stages to Statements

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Match each of the following five stages in cellular respiration with their corresponding statements.
Note: Each choice will be used exactly once.

Your Choice Prompt
Drop Your Choice Here 1. Glycolysis
Drop Your Choice Here 2. Electron Transport Chain (ETC)
Drop Your Choice Here 3. Cirtic Acid Cycle (TCA cycle)
Drop Your Choice Here 4. Chemiosmosis
Drop Your Choice Here 5. Pyruvate Oxidation

Drag one of the choices below:

  • A. At the end this stage, the four-carbon oxaloacetate has been regenerated, and the stage repeats.
  • B. Uses the electrochemical gradient to produce substrate-level phosphorylation energy molecules
  • C. This stage is entirely carried out by a large enzyme complex called the pyruvate dehydrogenase complex
  • D. For each molecule of glucose, this stage produces two (2) ATP and two (2) NADH molecules
  • E. Stage of cellular respiration that extracts energy from the electron carriers NADH and FADH2
 

Cellular Respiration Stages from Statements

Click to show Cellular Respiration Stages from Statements example problem

Which one of the following five stages in cellular respiration correspond to the statement 'Stage of cellular respiration that extracts energy from the electron carriers NADH and FADH2'.

 

Ordering Glycolysis Intermediates

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Glycolysis is an important metabolic pathway that breaks down glucose to produce energy. During the process known as glycolysis, molecules undergo transformations in a specific sequence. Understanding the order of these molecular transformations is a fundamental concept in biology.
Please place the following four (4) molecular structures of glycolysis in the correct order. The correct sequence of the molecule names is as follows:

  • 1. Dihydroxyacetone phosphate (DHAP)
  • 2. Glyceraldehyde 3-phosphate (GAP)
  • 3. 1,3-Bisphosphoglycerate (1,3BPG)
  • 4. 3-Phosphoglycerate (3PG)
Identify which chemical structure corresponds to each of the four (4) molecule names listed above. This will help you visualize the steps each molecule undergoes during glycolysis.
Here are some tips:
  • Think about what changes occur from one molecule to the next.
  • Consider the number of carbons and phosphates each molecule contains.
  • Molecules that are next to each other in the pathway are often similar.
  • Sometimes, working backwards can be helpful.

PositionYour choice
1 Drop Your Choice Here
2 Drop Your Choice Here
3 Drop Your Choice Here
4 Drop Your Choice Here

Drag each answer into the correct position:

  • 1.

  • 2.

  • 3.

  • 4.