39 replies to this topic

[freeztar]

Google Kreb cycle.

But seriously, you raise a good point about the "need for this series of reactions to take place". Let's look at the series of reactions first.



I suppose the need for this to take place could be explained, as suggested by InfiniteNow, as a product of abiogenesis (without life beginning, roughly translated).

Another explanation could envolve God, or perhaps Alien visitors with the intent of terraforming.

It's all so speculative.

[mynah]

Hello to all!
There is an interesting question in my textbook . It is obvious that we notice organisms because they reproduce. If there were to be only one, non reproducing organisms member of a particular kind, it is doubtful that we would have noticed its existence.
Let us ask a basic question-why do organism reproduce? After all, reproduction is not necessary to maintain the life of an individual organism, unlike the essential life processes as nutrition. On the other hand, if an individual organism is going to create more individuals, a lot of its energy will be spent in the process. So why should an organism waste energy on a process it does not need to stay alive?
Let us discuss the possible answers.

I take it what you want to know is why do organisms bother to reproduce, if it is not only metabolically expensive but also does nothing to extend the life of the organism?

Certainly a very interesting question, Mohit. My own take on it is that complex organisms arose from simple organisms, and those in turn arose from molecular structures at the very edge of life, because they happened to reproduce themselves. Reproduction was, therefore, not their goal as much as the cause of their existence at the beginning. Once established, the need to reproduce became a very powerful tool for survival.

[HydrogenBond]

One way to look at the energetics of life is to look at the hydrogen. If you look at H2, all by itself, without any other atoms present, the H is at its lowest possible energy state. This is reflected in solid hydrogen having the lowest melting point of any material in nature. In other words, the H in H2 is so stable there is almost no surface potential for attraction.

Although H2 is very stable by itself, the H2 is a high energy molecule with respect to oxygen. In this case, the potential for change is within the O and not in the H, since to become H2O, although the system energy is lower, the H now has a potential. In other words, the H2 doesn't interact but the H in H2O will interact strongly via hydrogen bonding. The H2 and O2 system energy is lowest as H20. The O's energy is also lowest as H2O. But hydrogen gains potential by becoming water, i.e., dipole charge.

That being said, when cells accumulates reduced food molecules,i.e., C-H, it is placing the H is a very low energy state relartive to H2, since both C and H have similar electro negativities. This low energy state for H is high energy with respect to O. The cell is designed to lower the potential of the H. But by lowering the H potential, the cell increases the O potential, until the system needs to discharge, driving the cell cycle.

At the lower end of hydrogen potential we have H2, which very few cells can make. The drag of the O, by going in the opposite direction makes this difficult. The cell sort of settles on low potential H using C-H, then N-H and then O-H. The latter, in turn, uses hydrogen bonding states. The H+ is the other end of the H spectrum having maximum potential.

An analogy of the cell are children in a playground. The lowest system energy will typically involve the biggest kids dominating play. The big kids are sort of O which be define the lowest system energy. The little kids (H) can't play easily with the aggressive big kids, dominating. The rest of inert nature is dominate by the big kids called oxygen, end of story. The cell is sort of like a teacher that comes to the playground to even the play allowing the small kids to participate in the games. But by doing this, the big kids are not allowed to play at full pace, so the little kids can better participate. But eventually, the teacher is called away (cell cycle) and the big kids take over again as the cell metabolizes very aggressively. But eventually the teacher returns (new cell) and helps the little kids so they can play.

[Mohit Pandey]

Life reproduces because cells are designed to gain potential energy. When a critical energy level is reached, the potential energy is used to create another duplicate of itself. If an electron enters an atom, energy is given off and the state becomes stable or at lowest energy. But life is designed to go the other way, gaining potential energy as it accumulates fuel reserves. When it reaches a critical potential energy, sort of the top of an energy hill, it begins to slide down the other side resulting in two at the bottom of the energy valley. These then start their climb until they reach the top of a new energy hill, etc..

That basically means that cell reproduction is a characteristic itself, deoesn't it? But my question is slightly different.
And your last post was off topic according to me.
If I didn't underatand it properly, then please clarify.

[max4236]

I've never reproduced. Peer pressure and nagging parents who want more grandchildren?

I'd imagine all the early organisms that liked to be bachelors died off and it's just the mutants who could reproduce that did so. I guess that's why sex is such a big thing now.

I don't think the genes have a will of their own. They just do their thing like good little programmed nanobots. I don't think genes feel joy when their host organism finds a snack or gets lucky. The organism as a whole though, it's in every creature's instinct to do it now.

[punchingsack]

I also want to know initially actually how did the first program of reproduction formed. I just believe it was out of mutation, but I think the mutation must have happened before the initial beings die out, and we know they were very simple beings which couldn't live long. So if they didn't get the ability of reproduction they had to pay the expectation to next generation, but the next generation would be different form them and their birth have to rely on chance of nature. That would be a long long period. Periods by periods finally the generation which was able to reproduce was born and survived. Wasn't the initial evolution of reproduction so aimlessly?

[freeztar]

I also want to know initially actually how did the first program of reproduction formed. I just believe it was out of mutation, but I think the mutation must have happened before the initial beings die out, and we know they were very simple beings which couldn't live long.

We don't really "know" anything conclusively regarding biogenesis or abiogenesis.

So if they didn't get the ability of reproduction they had to pay the expectation to next generation,

How is there a "next generation" without reproduction?

Periods by periods finally the generation which was able to reproduce was born and survived.

In trying to reason this statement, I find only paradox. Perhaps you can rephrase it punchingsack?

Wasn't the initial evolution of reproduction so aimlessly?

Why would the initial evolution of reproduction be aimless? It's an interesting idea, but it needs some support.

[punchingsack]

First of all, I'm sorry for my poor English expression.....

How is there a "next generation" without reproduction?

So a generation has to be from reproduction..... I get it. Then I meant upcoming , new beings.

Periods by periods finally the generation which were able to reproduce were born and survived.

In trying to reason this statement, I find only paradox. Perhaps you can rephrase it punchingsack?

An extremely long word passed, finally the new beings which was able to reproduce was born and reproduced their generations successfully. Their descendants continued and evolved.

Why would the initial evolution of reproduction be aimless? It's an interesting idea, but it needs some support.

That's just in my opinion. Since mutating is so random, would there be an aim in randomness? I think the purposeful selection by beings themselves based on natural selection didn't begin until the ability of reproduction invented.

[hallenrm]

Dear Mohit, I think your question is framed wrongly, consciusly or unconciously!

First of all, Let us ask, Do all biological organisms reproduce?

The obvious answer is no, there are plenty of examples of organisms that do not reproduce, may be not of an entire species!

The next question would be, Why do all members of a species that are capable of reproducing reproduce?

This is a bit tricky. There are of course many human beings who are perfectly capable of producing offsprings, but have chosen not to! Thus to exercise the choice of reproducing by those organisms that have it, has reasons beyond biology or chemistry.

Am I correct?

[Mohit Pandey]

First of all, thanks to all.

I think egg came first and egg came from an organism which had resemblance to the chicken species. Moreover it means that small variations(changes) in DNA resulted in the formation of chicken species. So that change will first occur in the egg.

Good discussion is going on. :)I think we have overlooked this post. Do you think it is correct?

[learnin to learn]

Hold on, Are you giving the example; at first there was an organism that resembled a chicken and ofter years of adaptation and genetic variation the chiken that we know of today was developed?

[freeztar]

First of all, I'm sorry for my poor English expression.....

No worries.

So a generation has to be from reproduction..... I get it. Then I meant upcoming , new beings.

Did you look at the link I posted about biogenesis?

An extremely long word passed, finally the new beings which was able to reproduce was born and reproduced their generations successfully. Their descendants continued and evolved.

It sounds like you are stating that reproduction is a byproduct of mutation. Is this what you mean?

That's just in my opinion. Since mutating is so random, would there be an aim in randomness? I think the purposeful selection by beings themselves based on natural selection didn't begin until the ability of reproduction invented.

While we encourage all our members to form their own opinions on topics, we also ask that opinions are backed up with supporting evidence. For example, your response quoted above would be more compelling if phrased in a way similar to this:

Because the definition of natural selection requires reproduction, it follows that natural selection did not begin until after reproduction existed.

Natural selection is the process by which favorable traits that are heritable become more common in successive generations of a population of reproducing organisms

Natural selection - Wikipedia, the free encyclopedia

Because I believe that reproduction was a byproduct of a de novo mutation, and mutations are mainly random, then I conclude that there was no aim in the advent of reproduction.

A response such as this gives the reader the opportunity to follow the links that back up your claims.

[questor]

Organisms reproduce BECAUSE their genes tell them to.The question is how, why and when do the genes cause this phenomenon? What else can be said on this subject? If something is not known, then the answer is... it is not known.

[Mohit Pandey]

A very good question Mohit!

The simplest answer, I suppose, would be instinct.

One must also think about "the chicken and the egg" and which came first. The organism must have come about from reproduction of another organism (unless we're talking about the first organism). So it makes sense that the organism continues with tradition because otherwise it would never have come to be.

learnin to learn! My previous post was a reply of this post.

[learnin to learn]

ok thank you Mohit

[taijishengnv]

a new news for it
An efficient way to make small molecules by repeatedly using just one coupling reaction to clip together pre-prepared chemical fragments is going commercial.

Martin Burke and colleagues from the University of Illinois, US, have demonstrated that by exclusively using Suzuki-Miyaura coupling (a popular reaction for making carbon-carbon bonds) they can make complex natural products from customised building blocks, such as double bonds and aromatic rings[1].

A range of suitable building blocks will be commercially available worldwide within eight months, ready to be bought off-the-shelf, Burke says, thanks to an agreement with a large chemical company. And the technique is already being used in the pharmaceutical industry to quickly make new collections of small molecules for drug screening.

'The impact of this, not the least of which will be making the power of small molecule synthesis available to the non-expert, could be extraordinary,' Burke told Chemistry World. 'Ultimately, we envision a collection of about 100 building blocks, and the chemistry is so simple that we feel very optimistic about automating the process.'

Burke's technique has parallels with the way small proteins are made, where amino acid building blocks are slotted together by repeated, and automated, use of peptide coupling. Just about any scientist can make or order a peptide today, but organic synthesis - even of small molecules - remains accessible only to highly-trained chemists.

All change

Burke hopes to change that with a series of haloboronic acid building blocks, of which he has published 9 prototypes so far. These reagents can be linked together repeatedly with Suzuki coupling because both the necessary coupling partners are contained in one bifunctional molecule - a halide at one end, a building block in the middle, and a boronic acid at the other end.

But such a reaction would quickly run out of control, with building blocks linking together haphazardly in any order, were it not for a key protecting group which shuts off the reactivity of the boron end, and, crucially, can also be removed without harsh reaction conditions that would affect the growing molecule. Earlier this year, Burke's team showed that the cheap and non-toxic MIDA (N-methyliminodiacetic acid) ligand masked boron's reactivity and was stable to anhydrous bases, yet could be removed at room temperature by any weak aqueous base - including sodium bicarbonate - when required [2].

This makes it possible to couple a protected fragment at its halide end only, then remove the MIDA ligand and expose the boronic acid, ready to link to another fragment and repeat.

[InfiniteNow]

a new news for it

Here's the source for taiji's post:

Off-the-peg organic synthesis goes commercial