2.3: Non-Glucose Alternatives

Question 1

Ture or False: Glucose is the only source of energy, carbon, and electrons for microorganisms.

Answer 1

False

Question 2

True or False: Polysaccharides, proteins (amino acids), and lipids can NOT be used as sources of energy.

Answer 2

False

Question 3

______ are typically molecules that are too large to be transported directly across the plasma membrane. Instead, microbes must secrete enzymes capable of degrading the polymer into smaller, more manageable subunits. Direct contact is often required by the microorganism to ensure maximal absorption.

Answer 3

Polysaccharides

Question 4

Describe Polysaccharides.

Answer 4

Polysaccharides are typically molecules that are too large to be transported directly across the plasma membrane. Instead, microbes must secrete enzymes capable of degrading the polymer into smaller, more manageable subunits. Direct contact is often required by the microorganism to ensure maximal absorption.

Question 5

___1___, similar to polysaccharides, must also be broken into smaller subunits or individual amino acids by enzymes called proteases. ___2___ are a rich source of nutrients as they are a source not only of carbon and energy but also nitrogen and sulfur.

Answer 5

1. Proteins
2. Amino acids

Question 6

Describe Proteins.

Answer 6

Proteins, similar to polysaccharides, must also be broken into smaller subunits or individual amino acids by enzymes called proteases. Amino acids are a rich source of nutrients as they are a source not only of carbon and energy but also nitrogen and sulfur.

Question 7

______ are a rich source of nutrients as they are a source not only of carbon and energy but also nitrogen and sulfur.

Answer 7

Amino acids

Question 8

Amino acids are a rich source of nutrients as they are a source not only of carbon and energy but also ___1___ and ___2___.

Answer 8

1. nitrogen
2. sulfur

Question 9

______ are rich in energy, often having many reduced carbon molecules. Lipases separate the fatty acid chains from the glycerol backbone. The backbone is processed for carbon and energy, whereas the fatty acid chain is degraded via the β-oxidation pathway into acetyl-CoA, which feeds directly into the Krebs cycle —a highly efficient process that overlaps with both the TCA and electron transport chain cycles. For instance, for each lipid-derived carbon atom, 48 molecules of ATP are yielded, compared to the 38 molecules of ATP produced from glucose.

Answer 9

Lipids

Question 10

Describe Lipids.

Answer 10

Lipids are rich in energy, often having many reduced carbon molecules. Lipases separate the fatty acid chains from the glycerol backbone. The backbone is processed for carbon and energy, whereas the fatty acid chain is degraded via the β-oxidation pathway into acetyl-CoA, which feeds directly into the Krebs cycle —a highly efficient process that overlaps with both the TCA and electron transport chain cycles. For instance, for each lipid-derived carbon atom, 48 molecules of ATP are yielded, compared to the 38 molecules of ATP produced from glucose.

Question 11

______ separate the fatty acid chains from the glycerol backbone.

Answer 11

Lipases

Question 12

The ___1___ is processed for carbon and energy, whereas the ___2___ is degraded via the β-oxidation pathway into acetyl-CoA, which feeds directly into the Krebs cycle —a highly efficient process that overlaps with both the TCA and electron transport chain cycles.

Answer 12

1. Backbone
2. fatty acid chain

Question 13

For each lipid-derived carbon atom, ___1___ molecules of ATP are yielded, compared to the ___2___ molecules of ATP produced from glucose.

Answer 13

1. 48
2. 38

Question 14

For each ___1___ carbon atom, 48 molecules of ATP are yielded, compared to the 38 molecules of ATP produced from ___2___.

Answer 14

1. lipid-derived
2. glucose