- Amino acids and proteins questions
- Central dogma of molecular biology
- Central dogma - revisited
- Amino acid structure
- Peptide bonds: Formation and cleavage
- Special cases: Histidine, proline, glycine, cysteine
- Isoelectric point and zwitterions
- Classification of amino acids
- Four levels of protein structure
- Conformational stability: Protein folding and denaturation
- The structure and function of globular proteins
Central dogma of molecular biology
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- Just a note on the history. Watson and Crick discovered the structure of DNA and both scientists also made huge contributions to the understanding of all these processes. Neither "discovered" the central dogma but rather contributed to its understanding. It was Crick who coined the term Central Dogma.(34 votes)
- Let's not forget the contributions of Rosalind Franklin (and Maurice Wilkins).(278 votes)
- I was thinking of a kind of analogy that can help us not mix "transcription" and "translation".
So we could imagine DNA as a book. The book is transformed into a script (=RNA).
The script is then used to create something else - a movie(=protein).
So the two nucleic acids are somehow similar because they are letters (C,G,A,T or U) on a piece of paper. That's why it's enough only to "transcript" the content from the original piece of paper to another just by changing it a little bit (T->U).
But the protein is a whole different thing - like the movie! So it's necessary to "translate" it into this... digital thing... you get it! :))
What do you think, is it a good analogy?(31 votes)
- I think that's a good analogy! I mean analogies are very personal. Here's the way I've always used to remember the differences between transcription and translation.
Let's start with transcription, we're working from DNA to RNA. The one common thing between these two is they are both written in nucleotides. (A, T/U, G, or C). So when I think of transcription, I think of old-school scribes (you know, the people who take writings and make it look super nice and stuff). So I always think of DNA-> RNA as transcribing something from like print to cursive. Both are in the same language, just written differently. (English Print to English Cursive)
Next to translation, This is going from RNA to Proteins. Now this time you're moving from nucleotides to amino acids which are totally different. So I think of plugging this through google translate and working with a whole new language. Like when you translate something from English to Spanish. So you're working with English (DNA and RNA) and translating it into Spanish (Proteins). Does that make sense? :)(17 votes)
- Journey to MEd School starts here. Bloody heck, here we go again.(16 votes)
- Alphabetically, transcription occurs before translation, so that's probably the most helpful thing to remember which happens first.(14 votes)
- Why isn't Rosalind Franklin acknowledged in the discovery?(8 votes)
- I know most texts state that Watson and Crick realizing not only the DNA structure but the central dogma too. The historical fact is that Rosalind Franklin is the person who worked on and discovered the structure of DNA. While it is difficult to challenge the prevalence of credit given to Watson and Crick, it is time to give the credit to Rosalind Franklin- the person who ACTUALLY discovered the structure of DNA.(7 votes)
- Why is it referred to as dogma?(5 votes)
- I hope someone discovers something about DNA soon that would completely rip the central "dogma" to shreds. They make this sound too much like a religion with its dogma. Just because someone called it "the central dogma" doesn't mean that it IS dogma. There are no facts in science; only observations.(2 votes)
- I hope the Science Community begins to point out the fact that Watson and Crick plagiarized of Rosalind Franklin's work on DNA structure. They are not the people who discovered the structure of DNA, and it is time to correct this historical inaccuracy.(1 vote)
- I agree! Also, Franklin's discovery actually occurred with the help of Raymond Gosling, another scientist who is frequently overlooked too. These discrepancies are indeed often acknowledged but certainly not often enough... I think you might be pleased to know that Khan does speak to this in the Central Dogma - Revisited video though! (https://www.khanacademy.org/test-prep/mcat/biomolecules/amino-acids-and-proteins1/v/central-dogma-revisited)(2 votes)
- why amino acids are amphoteric in nature?(1 vote)
- The C-term is acidic and the N-term is basic, and each individual amino acid has both of these ends. Also, some of the R groups can be one or the other as well.(2 votes)
- when aa form sulfur bridges are they not connected in three places(1 vote)
- So what exactly is the central dogma of molecular biology? Well, really it could just be called the central dogma of all of life because it explains how you and I take this conglomeration of genetic information from each of our parents, and how this information gets transferred into generating a full-blown human being, like you and me. So some very clever scientists, Francis Crick and James Watson, or "Watson and Crick," as they're often referred to as, are credited with discovering this dogma, which they say deals with the detailed residue-by-residue transfer of sequential information. Or, as Marshall Nirenberg, who won the Nobel Prize in Physiology and Medicine, once said, "DNA makes RNA makes protein." And I think this simple explanation really just says it all. So let's explore this concept a little bit further. So we have three major players here. DNA and RNA are nucleic acids, which are made up of nucleotides, and proteins are made up of amino acids. And the information starts at the most basic level stored as DNA, which can then be re-stored as DNA when DNA copies itself in a process called "replication." Then DNA can be copied into RNA in a process called "transcription." And then finally you can use the information in RNA to synthesize a protein in a process called "translation." Now since DNA, RNA, and protein are linear polymers, this means that each individual unit, or monomer, is only attached to, at most, two other units. So say we have a monomer, which is just one unit. They are connected in a series like this, which makes it a linear polymer, and this is the same for DNA if each of these is a deoxyribonucleic acid, for RNA if it's a ribonucleic acid, or a protein, which are just amino acids all connected in a linear polymer. So what does this mean? This means that the specific sequence of each of these monomers effectively encodes information, and that that transfer of information is faithfully preserved from DNA to RNA to protein. Each polymer sequence is used as a template for the synthesis of the next polymer. And you could go into any step in this sequence and determine what the corresponding polymers would look like. So in other words, you could take DNA and obviously figure out what the corresponding RNA would look like, and then what the corresponding protein would look like. So this whole process is the central dogma. It can sometimes be a little bit tricky to keep all of these terms straight, so I'll try to break it down a little bit for how I like to remember them. For DNA, I think it's pretty easy. When you go from DNA, and DNA makes a copy of itself, it's called replication because DNA is just replicating itself. It's making the same copy of itself. Transcription and translation, on the other hand, it's kind of easy to get these two terms mixed up. One of them obviously is talking about DNA to RNA, whereas the other one is talking about going from RNA to protein. So if you look at the word transcription, it has the word "script" in it, so I think of it as going from one written form to another kind of written form, and both use nucleic acid, so they both use this sort of alphabet, if you will, of nucleic acids. And so you're just going from one kind of alphabet to the next kind of alphabet. Translation, on the other hand, which is also the same term that we use when translating one language to another, describes going from nucleic acid to amino acid, so it's like you're using one kind of language and going to another kind of language, because you're going from nucleic acid building blocks to amino acid building blocks. So hopefully that helps you keep these terms straight a little bit. So what did we learn about the central dogma? Just remember the simple statement that DNA makes RNA, which makes protein.