ever thought of photosynthesizing?

*nearly a month ago*
   sitting in a very boring math class on shares & dividend i let my mind wander and the thought of humans with chloroplasts crossed my mind. is it possible? inserting chloroplasts in every epidermis cell? or maybe a separate organ reserved for chloroplast containing cells? will it work? think about it... if it does work, the implications are huge. WE COULD ERADICATE WORLD HUNGER!!

okay so let's look at why this should be possible:

Plant Cell [Click for larger view]

   animal cells are pretty much the same as plant cells. if i remember last year's bio correctly, the only differences are:
 - we've got no cell wall

 - plant cells have larger vacuoles whereas in us they're small or sometimes even absent

 - most plant cells do not have centrioles and lysosomes but we do

 - plant cells have plastids, unlike animal cells.

    so inserting chloroplast [a plastid] shouldn't pose any issues because as i see it:

Animal Cell [Click for larger view]

 - cell walls are basically for protection and turgidity, we can do without them. 

 - a couple of extra bodies like the centriole and lysosome shouldn't exactly hinder our chloroplast's functionality, right? 

 - on vacuoles: are they really that necessary? they just store substances in solution, don't they?

 - our plastid, chloroplast, is just another tiny organelle that's looking to enter our being. what does it contain? thylakoids. what do the thylakoids contain? chlorophyll, the green pigment which helps plants obtains energy from sunlight and blah blah. we all know that bit. does a sunlight trapping, poor absorber of the green portion of the spectrum pigment possess the potential to cause damage to an animal's body? sounds pretty harmless to me.

   oh and btw, chloroplasts in animals is not entirely unheard of. meet the Elysia chlorotica:

 this amazing creature [also called the green sea slug] consumes algae and then utilises the chloroplasts present in them to capture the sun's energy, JUST LIKE A PLANT, through photosynthesis. the whole process is termed as kleptoplasty. this one doesn't need to worry about going hungry, he's perfectly capable of surviving on the sugars manufactured by his own chloroplasts. although no other animal has been found to possess this extraordinary ability, we now know that animals can be capable of supporting chloroplasts.

now let's check out the flaws:

Simplified Diagram of a Chloroplast

   the first thing that comes to mind is the enormous amount of energy animals need when compared to plants. this brings us to the lack of sufficient surface area on the animal body. the amount of area that needs to be exposed to the sun to produce enough food to fulfill all our energy requirements... yes, you can imagine. a minor plant whose biological system is so simple compared to ours takes every measure to maximize its exposed surface area and then you look at us and the insane amount of energy we need to keep all our organ systems alive and kicking. but then again, who said we need to be solely dependent on photosynthesis? we could ingest foods just like we normally do, photosynthesizing can be an added bonus or an emergency function.

   next thing: to me a chloroplast doesn't seem to pose much of a threat to the body. but does our brain agree? i'm pretty sure that on insertion some kind of defense mechanism will be triggered because our genes will most probably recognize the chloroplast as a foreign body and set out to destroy it. our bodies lack the - i don't know what to call it - *thing* that supports the chloroplast and knows that it's okay, that little green thing is here to help. we'll also need a sophisticated transport system to carry the manufactured food and store it for future use. too much of glucose accumulating in our cells - not so good.

oh and not to forget, chlorophyll in your skin? you sure you don't mind turning a shade green?

   that's all i could come up with. but all of that's just logic and real-world-facts for you. you most definitely don't need those to make believe, now do you? you can picture yourself in your skimpiest bikini [or nude, whichever way you prefer] out in the sun, ever so green. go on dearest, go ahead and photosynthesize!