TP36 Metabolism

Metabolism

• Catabolism / Anabolism
• Glycolysis / Gluconeogenesis
• Pentose phosphate pathway (PPP)
• Oxidative phosphorylation

Question 1

What is the yield of ATP from the complete oxidation of glucose to CO₂? Break down the yield as a table with one entry for each point where ATP is consumed. Use the metabolic maps in the slides . There are different values for the The ATP yield from the complete oxidation of one molecule of glucose in the literature. This variation arises due to differences in the efficiency of the processes involved. Compile the reasons for these variations.

💡 Search for the Khan Academy Unit 10: Cellular respiration. Khan Academy has lots of accessible information on metabolism. 💡The PL Glucose Consumption could be helpful.

Question 2

What is the purpose of the Malate-Aspartate Shuttle and the Glycerol-Phosphate Shuttle?

Question 3

Why is glucose 6 phosphate isomerized to fructose 6 phosphate in glycolysis?

Question 4

A rabbit was analyzed, and it was found that the enzyme lactate dehydrogenase had a mutation that made it practically inactive. What would happen to the rabbit if it had to run hard to escape a predator?

Question 5

If [1-14C] glucose (glucose labeled at C-1 with the radioisotope 14C) is metabolized in the human glycolytic pathway, where is the location of 14C in the lactate product? Explain.

Question 6

Where should the 14C be located in the initial glucose to ensure that all the 14C is released as 14 CO₂ during fermentation to ethanol by yeast? Explain.

Question 7

Calculate the percentage of energy released in the form of ATP from one molecule of glucose and compare it with that obtained when using a molecule of glucose from endogenous glycogen and a molecule of maltose.

Question 8

How efficient is metabolism? Compare the free energy of complete combustion of glucose and combustion of the same amount of glucose in a chemical reaction.

Question 9

Why is the Bakers yeast S. cerevisiae electron transport chain less efficient than that of mammalian cells for example? This question requires research online! For example, have a look at Figure 4 in Sharma 2010 compare with the electron transport chain in the slides.

Question 10

This is an individual exercise for each student. Your task is to calculate the number of ATP molecules (in mmoles) from the simultaneous consumption of a mixture of carbohydrates sources. Find the quantities for your mixture of substrates in the TP36 spreadsheet.

This question will require you to search for information about the catabolism of your compounds. Assume aerobic conditions and that the final products are CO₂ and H₂O.

Please answer in the same spreadsheet as as indicated for the first example student "Max Maximus".