Jimmy Hopkins (yes, that's his name) is a extremely weird organism. For one thing he is extremely large, but on the other hand, he is extremely weird, because of one thing- He is an unicellular organism
You heard it right. JH is just nothing but a giant unicellular organism about 50m across and 30m tall, resembling a giant bacterium. JH has a extremely hard capsule made of cellulose and lignin, to protect it from abrasions and dents. Inside JH is a collection of thousands of chloroplasts to produce food. JH's mitochondria are really nothing more than a bunch of oversized mitochondria that produce a lot of energy. Since JH is so massive, it would die if it were to exist on land, so it simply swims in the ocean. JH has multiple flagella that are about twice as long as the host organism itself, which help it to propel through at high speeds through the water. In short, JH is basically an upscaled version of an cyanobacteria, except with chloroplasts and a proper nucleus. JH is rod shaped. Sorta like this:-
However, JH's size and unique shape makes it an tempting target for creatures, which means that JH has multiple predators. So JH needs to have a energy source that can provide sufficient energy for escaping.
The problem is, if JH were to use ordinary glucose for energy, then it would have to use so much glucose that the sheer weight would offset the amount of energy to propel it, meaning that JH would move sluggishly. JH needs to move extremely fast, literally plowing itself through the water. JH cannot produce short bursts of energy, i.e. reach high speeds for just a few seconds like a cheetah and slow down. JH needs to be moving at breakneck speeds for at least a few minutes to escape its predators. So JH would need a more energy-dense substance to propel itself, without just exhausting its energy supply.
Initially I was thinking that JH would use nuclear reactions to propel itself forward at these speeds, but I am no longer optimistic about this due to the reasons below:
- There is a reason why cheetahs don't use fission reactors to propel themselves. Nuclear fuel is overkill. If JH were to use uranium/plutonium for propulsion, then it would self-destruct due to the sheer amount of radiation being released which would cause it to disintegrate.
- Nuclear energy is non-rechargeable i.e. you can renew your glucose supply by making glucose, for e.g. but you cannot make "uranium" to replenish its energy supply, you would need a supernova to make uranium, not just the meagre energy of a cell.
- Nuclear Fusion- Do I need to explain myself?
So, although JH is still using the glucose from its chloroplasts for metabolic purposes like maintaining cell temperature and peacefully swimming, it needs a emergency fuel, one that is much more energy-dense than glucose, which it can use during crisis mode, i.e. when it is under threat from predators or escaping a natural disaster, so that it can flee the area.
The final question is:
What kind of energy-dense fuel would JH use in order to flee at high speeds without getting exhausted quickly?
- The fuel should be something that has a much higher energy density than glucose, i.e. that a certain amount of the fuel would produce more amount of energy than a similar amount of glucose.
- No nuclear fission or fusion, please.
- Something that can be easily replenished by JH.
EDIT: Some clarifications:-
- JH does not photosynthesize in the deep ocean. It instead comes up to the surface for brief periods of time to produce food.
- JH is rod-shaped, not spherical
- JH uses the oxygen that it gains from the photosynthesis for metabolism
- JH is not hostile to symbiotes. In fact, it is extremely calm and passive towards animals such as anemones and friendly fungi, which protect JH from predators (in case of fuel depleteion), in return for oxygen and glucose that JH synthesizes, and enhanced mobility. So JH can allow them to "roost" on the surface of JH. JH is only hostile towards predators and enemies.