Does all living stuff need a source of food?

Question

When we talk of simple cells or proteins or amino acids as the earliest building blocks of life, is it understood that they all had a source of food or is food unnecessary for these to exist?

How long, if they do require nourishment, could they survive in what might be thought of as a hostile environment?

Please help a non-scientist in his quest to understand evolution.
Thanks

Answer 1

Yes. all life requires food, survival time when deprived of food varies from organism, some can survive decades, 17 year Cicadas dont eat for 17 years, some (like shrews)have to eat close to their own weight in food daily or they starve.

Answer 2

Basically, amino acids make up proteins, which make up the cell, which is the building block. So in a sence they're the building blocks of the building blocks. They don't require nourishment, at this point they're just complex polymers. The amino acids Guanine Tyhmine Adeine Cytoceine make up part of DNA they're the parts on the inside. Every three of these amino acids, or a codon, is literally a code for a specific protein to be created. Then the protein is made by the ribosomes, and becomes a part of the cell. Of course that's the really basic watered down version, and of course if you have the time to look up all the big words involved, wikipedia explains these sort of things superbly.

Answer 3

Actually, living things don't need a source of food...what they need is a source of energy. Sugars just happen to contain a readily available source of energy within their chemical bonds. Some living things get that energy from food, whereas others get it from the sun (photosynthesis) or chemicals (chemosynthesis). Both of these types of synthesis will make types of sugars. The sugars will store the energy until the cell is ready to use it.

Because energy cannot be created or destroyed, cells will take the energy they get and transfer into a type of chemical energy that the cell can use (usually a chemical called ATP). This is kinda like taking rechargeable batteries and plugging them into the recharger to fill them up with energy. These batteries can then be used...but recharged again.

Amino acids are like lego pieces...put them together and you make a protein. Many proteins need ATP to perform their job function...without the ATP, the protein won't work. Kinda like the remote control car. You can hit the forward switch all day long, but until the batteries are in it, the car ain't going anywhere.

Survival length: each cell is unique. Some will die within minutes in the absence of ATP...actually, a couple of years ago scientists released a drug that would kill a certain germ by destroying the ATP factory of that germ cell.

Answer 4

Amino acids can be synthesized outside of a living organism, and you can also synthesize strands of RNA outside of an organism, proteins as well. Chemistry of these components can happen randomly and indiscriminately as long as the temperature stays "just right."

Simple cells are still organisms, so yes, these do need to have access to water and nutrients, and access to at least one chemical pathway to generate energy.

The interesting thing about single-celled organisms of all kinds, many of them have adapted a way to put themselves into "stasis" when their primary source of energy is depleted.

There isn't a rule by which you can say an organism can only survive for so long before they die, without talking about a specific organism.

If you're wondering about the actual genesis of life itself, this isn't a question biology can answer: it's a study for specialists in organic and inorganic chemistry. Evolution, and thusly, Biology, can only describe life after life came to be; with no mode of transmitting genetic information, there can be no evolution.

Answer 5

Simple chemicals like amino acids do not require food to go on existing. However, by the same token, individual amino acid molecules are not alive.

In the 'primordial soup', eventually a molecule was randomly created that interacted with surrounding molecules, and transformed them into copies of itself. You could say it was 'digesting' them, if you used the term loosely. After a while, random mutations, most likely caused by UV light, led to multiple molecules all capable of reproducing themselves. At this point, the molecules were all competing. The ones capable of reproducing the fastest became the most dominant. Eventually, the best molecules assembled themselves into more complicated structures, enabling them to eat more of the organic soup. At this point, you would say that life had probably begun, but the exact point is fairly arbitrary.

Answer 6

Yes, all forms of life need a source of food. Different forms may need different food though. Humans are omnivores, and of course eat plants and meat (unless your a vegetarian). Depending on an animal, they may be a carnivore (meat eater), herbivore (plant eater), or an omnivore like humans. Plants make their own food from the sun's eneregy through a process called photosynthesis. Bacteria feed on dead cells. Fungi usually feeds on dead plants, but sometimes people can get a fungal infection such as athlete's foot.

Amino Acids:
As far as I know they are cells, and would need the energy to live, and help in the coding of DNA.

Hope this helps!
EDIT: (It probably won't much, I just read the entire question >_<)

Answer 7

yes all life requires food, even archeabacteria (ancient bacteria; Prokaryote- no cell nucleus) there are two types of nourishment that an organism needs we for example are heterotrophic meaning we need to consume food for caloric energy. bacteria are autotrophic meaning they create their own food from the sun or inorganic particles ( some even eat oil and nuclear waste.) Fitness( the ability of an organism to be well suited to its environment) one of Darwin's ideas helps create a good point about how an organism EVOLVES to fit its environment. say we have the amazon jungle plants at the bottom of the canopy can't get light so are not well suited unless specific traits are passed on genetically for not needing much sun light. trees at the top of the canopy receive the trees at the bottoms sunlight.... survival of the fittest.

Answer 8

in order to sustain life (not growth and development, let alone reproduction), we do need need. food is in the form of biomacromolecules: carbohydrates, lipids, even proteins. Although we all know that the preferentially metabolized substrate is carbos: glucose, fructose etc. This metabolism is called cellular respiration, which generates ATP (also known as the molecular energy currency) which is used to fuel all our cellular activities.

in the absence of food, your body metabolize the existing carbohydrates it has, then glycogen stores, lipids, amino acids. When it uses amino acids it will be breaking down proteins to provide the supply, which means many cellular functions will be impeded, because they all use proteins in one form or another.

this depletion is especially rapid when oxygen is deficient. respiration will be like 18 fold less efficient.

you ask how long. it depends on what kind of cells, and how hostile. i cultured several lines of leukemic cells in my lab, and you just can't kill them by not giving them food. I read that Hela lines, which means cells from that legendary cancer tumor, can survive the harshest of conditions. yet on the other spectrum there are things like stem cells. I cultured 2 lines of hematopoietic progenitors and they die with slight changes in oxygen tension. go figure.