Do you believe we are being visited by intelligent aliens from another planet?

valjean wrote:

dmb wrote:

You say these things so confidently, and there certainly are appealing arguments to made about self-organizing processes.

Can you show me though how proteins were made?

I'm not sure what you're asking exactly. Like how proteins were made abiotically? The condensation of two amino acids can occur abiotically. The carboxyl of one amino acid becomes coordinated with some electron withdrawing group and then it gets attacked by the nucleophilic amine on another amino acid, which forms an amide bond. Amino acids are easy to form abiotically, and metal ions, phosphates, etc can behave as electron withdrawing groups.

How a cell makes proteins? It does the same thing, but it uses other proteins to hold the amino acids in place so that they're more likely to react.

How we make them in a lab? That's a little more complicated, but usually we'd use a carbodiimide (or we'd just make a cell do it for us).

Note that there's a lot of contention among biologists about what the first macromolecule was. IMO it's unlikely that proteins were the first macromolecule. I think nucleic acids are a better candidate, but there are arguments against that position

valjean wrote:

Bluebeaming wrote:

I'm not religious. We can't get anything close to life in a lab. You need to learn more about the science of biology and chemistry. Dna alone is so complex it's probability happening again on another planet is not possible

Complexity has nothing to do with the likelihood of abiogenesis. Complexity can be achieved by the repetition of the simplest processes imaginable. The formation of DNA and other biomolecules are the result of many simple chemical reactions - they form because they represent energetically favorable molecular configurations. If you shake around a bucket of biological precursors for long enough, it will self-assemble into DNA because it is more energetically favorable for the precursors to be linked up into a long macromolecule than it is for them to stay separate. The formation of DNA is an exothermic process!

This is the same reason that a bucket of rocks will separate out by size when you shake it. All physical systems seek the lowest energy state possible. When you shake a bucket of rocks, they get rid of as much gravitational potential energy as possible, and the way they do that is by sinking to the lowest possible point in the bucket. When you shake a box of biological precursors, they get rid of as much chemical energy as possible, and the way they do that is by forming chemical bonds so they can share each other's electrons and dump the remaining energy into their environment as heat.

Biomolecules are the inevitable result of thermodynamics. If you confine carbon, nitrogen, oxygen, sulfur, phosphorous, and hydrogen in a stable medium where they can freely interact and expose them to energy inputs that can alter their valence chemistry (e.g. UV radiation, redox reactions with metal ions) they will eventually link up and form complex chemical behemoths. Some of those behemoths will catalyze their own formation. These autocatalytic molecules will compete with one another until eventually one of them gains the ability to isolate itself by associating with amphiphilic phospholipids and forms a proto-cell. We can do all of these steps in vitro

vaIjean wrote:

dmb wrote:

What you’re doing is trying to describe how a car starts by describing what it does when it is running. If you’d prefer mathematically precise language, you are confusing a transient and steady-state solution.

You have identified requirements for life to proceed how we know it, but that does not define a mechanism.

The language that you use suggests that you believe RNA started it all. Ok, show me how RNA was formed in the absence of the other structures, ie ribosomes.

There is some belief that natural structures in clays, or zeolites could have functioned as membranes with the mineral elements serving as catalysts. You could go Dow that road, but you’re still hand waving.

Thermodynamically speaking, the car started the minute that earth was cool enough for liquid water to seep into its crust. Everything else is a chemical downhill tumble. Nucleotides naturally condense into small RNA oligos abiotically just like amino acids condense into peptides abiotically. Some of these oligos have secondary structures confer autocatalytic activity. The autocatalytic structures produce copies of themselves and multiply exponentially. Eventually many types of autocatalytic RNAs compete for raw materials and interact with one another. Some of them gain the ability to recruit amino acids and catalyze amide bond formation - and thus the a proto-ribosome is formed. Such is the RNA world hypothesis

Many modern enzymes use metal ions as redox centers, so it's not very far-fetched to suggest that biochemistry evolved around mineral-bound metal ions. Personally I find the hypothesis that RNAs formed in association with pi-stacked PAHs very compelling

valjean wrote:

Bluebeaming wrote:

I'm not religious. We can't get anything close to life in a lab. You need to learn more about the science of biology and chemistry. Dna alone is so complex it's probability happening again on another planet is not possible

Complexity has nothing to do with the likelihood of abiogenesis. Complexity can be achieved by the repetition of the simplest processes imaginable. The formation of DNA and other biomolecules are the result of many simple chemical reactions - they form because they represent energetically favorable molecular configurations. If you shake around a bucket of biological precursors for long enough, it will self-assemble into DNA because it is more energetically favorable for the precursors to be linked up into a long macromolecule than it is for them to stay separate. The formation of DNA is an exothermic process!

This is the same reason that a bucket of rocks will separate out by size when you shake it. All physical systems seek the lowest energy state possible. When you shake a bucket of rocks, they get rid of as much gravitational potential energy as possible, and the way they do that is by sinking to the lowest possible point in the bucket. When you shake a box of biological precursors, they get rid of as much chemical energy as possible, and the way they do that is by forming chemical bonds so they can share each other's electrons and dump the remaining energy into their environment as heat.

Biomolecules are the inevitable result of thermodynamics. If you confine carbon, nitrogen, oxygen, sulfur, phosphorous, and hydrogen in a stable medium where they can freely interact and expose them to energy inputs that can alter their valence chemistry (e.g. UV radiation, redox reactions with metal ions) they will eventually link up and form complex chemical behemoths. Some of those behemoths will catalyze their own formation. These autocatalytic molecules will compete with one another until eventually one of them gains the ability to isolate itself by associating with amphiphilic phospholipids and forms a proto-cell. We can do all of these steps in vitro

Bluebeaming wrote:

valjean wrote:

Complexity has nothing to do with the likelihood of abiogenesis. Complexity can be achieved by the repetition of the simplest processes imaginable. The formation of DNA and other biomolecules are the result of many simple chemical reactions - they form because they represent energetically favorable molecular configurations. If you shake around a bucket of biological precursors for long enough, it will self-assemble into DNA because it is more energetically favorable for the precursors to be linked up into a long macromolecule than it is for them to stay separate. The formation of DNA is an exothermic process!

This is the same reason that a bucket of rocks will separate out by size when you shake it. All physical systems seek the lowest energy state possible. When you shake a bucket of rocks, they get rid of as much gravitational potential energy as possible, and the way they do that is by sinking to the lowest possible point in the bucket. When you shake a box of biological precursors, they get rid of as much chemical energy as possible, and the way they do that is by forming chemical bonds so they can share each other's electrons and dump the remaining energy into their environment as heat.

Biomolecules are the inevitable result of thermodynamics. If you confine carbon, nitrogen, oxygen, sulfur, phosphorous, and hydrogen in a stable medium where they can freely interact and expose them to energy inputs that can alter their valence chemistry (e.g. UV radiation, redox reactions with metal ions) they will eventually link up and form complex chemical behemoths. Some of those behemoths will catalyze their own formation. These autocatalytic molecules will compete with one another until eventually one of them gains the ability to isolate itself by associating with amphiphilic phospholipids and forms a proto-cell. We can do all of these steps in vitro

You don't understand thermodynamics like you think. The bucket of molecules will never form dna. The bucket of rocks separate, not because of entropy, but the opposite. It facilitates the process of less chaos and more order. Entropy is a result of the first mover and it can never be undone, but a system will always move towards a lower energy state...less complex, more simple. It takes outside intervention to continue to drive more complexity