Metabolosomes

Organelle Details
Metabolosomes	[[File:|center|100px]]
[[File:|300px]]
Base Cost (MP)	45
Requires Nucleus	No
Processes	Protein Respiration
Enzymes	None
Size (Hexes)	1
Osmoregulation Cost	1
Storage	0.5
Unique	No
Upgrades	None
Internal Name	metabolosome

Metabolosmoes perform Protein Respiration, a form of Aerobic Respiration inferior to that of Mitochondria. It is the conversion of Glucose into ATP with the use of Oxygen.

Requirements

No requirements

Processes

Protein Respiration: Glucose → ATP @ Oxygen

Protein Respiration is a method of energy production performed by Metabolosomes. An input of glucose is needed for this to take place, and the rate of the process scales with the amount of environmental Oxygen.

Modifications

No modifications.

Effects

No effects.

Upgrades

No upgrades.

Strategy

TBA

Scientific Background

Unlike eukaryotes, prokaryotes do not have membrane-bound organelles. In other words, their organelles do not have membranes. Instead, prokaryotes like bacteria construct compartments out of proteins. A metabolosome is an example of such a compartment, officially referred to as a bacterial microcompartment (BMC). BMCs are composed of a polyhedral protein shell around 100-200 nm large that looks similar to a virus capsid. The proteins that make up the shell typically have (semipermeable) pores that allow different compounds (substrates and products) in and out of the organelle. They concentrate enzymes and proteins involved in specific metabolic processes in one spot, ensuring their success. The protein shell also acts as a physical barrier, allowing BMCs to conduct metabolic reactions that create toxic or unstable intermediate compounds.

Metabolosomes are a catabolic type of BMC, and are involved in the degradation of different carbon sources such as glycerol and amino acids. There is no clear evidence that the process of breaking down glucose takes place in metabolosomes, however it is not unreasonable to assume that it could do so.

Aerobic cellular respiration (glucose -> ATP)

The actual process of breaking down glucose for energy takes place in several steps in both prokaryotes and eukaryotes. The only difference is where some of the enzymes are located and organized. Below is a summary of the various reactions with the full names of the molecules and the chemical formulas/abbreviations.

Glycolysis: Glycolysis takes place in several steps, catalyzed by 10 different enzymes with 11 intermediate compounds. The end result is one glucose produces two pyruvate molecules, two ATP molecules and two NADH molecules (which are later converted to 4-5 ATP molecules). Glycolysis occurs in the cytoplasm of both eukaryotes and prokaryotes

The net reaction looks like this:

Glucose + 2 ADP + 2 NAD+ + 2 Pi → 2 pyruvate + 2 ATP + 2 NADH + 2 water

If you'd like to learn more about glycolysis, visit https://www.tuscany-diet.net/2018/02/06/glycolysis/.

Linker reaction:

This reaction connects glycolysis to the next major reaction cycle in ATP production: The Krebs cycle, also known as the citric acid cycle.

2 Pyruvate + 2 CoA + 2 NAD+ + 2 Pi → 2 acetyl-CoA + 2 NADH + 2 CO2

Krebs cycle:

2 acetyl-CoA + 6 NAD+ + 2 FAD + 2 GDP + 2 Pi + 4 H2O → 2 CoA + 6 NADH + 6 FADH2 + 4 H+ + 2 GTP + 4 CO2

Electron transport chain and oxidative phosphorylation:

10 NADH + 10 H+ + 2 FADH2 + 2 GTP + 6 O2 -> 25ATP + 3 ATP + 2 ATP

Remeber there is also 2 ATP produced by glycolysis. This brings the total amount of ATP produced to 32.

However, the actual maximum amount of ATP possible varies between species and tissues due to differences in the amount of hydrogens pumped across the mitochondrial membrane by the electron transport chain. In other words, the amount of ATP generated per NADH and FADH2 molecule depends on the species. The total amount is commonly stated as being between 36-38 ATP.

Abbreviations:

ATP: Adenosin TriPhosphate ADP: Adenosine DiPhosphate NAD+: Nicotinamide Adenine Dinucleotide NADH: Nicotinamide Adenine Dinucleotide (Hydrated) FAD: Flavin Adenine Dinucleotide FADH2: Flavin Adenine Dinucleotide (Hydrated) GTP: Guanosine TriPhosphate GDP: Guanosine DiPhosphate Pi: inorganic Phosphate CoA: Coenzyme A CO2: Carbon Dioxide