Francis Crick Quotes

Unfortunately it makes the unambiguous determination of triplets by these methods much more difficult than would be the case if there were only one triplet for each amino acid.

DNA is a code of four letters; proteins are made up of amino acids which come in 20 forms. So the ribosome is a very clever machine that reads one language and operates in another.

The meaning of this observation is unclear, but it raises the unfortunate possibility of ambiguous triplets; that is, triplets which may code more than one amino acid. However one would certainly expect such triplets to be in a minority.

Do codons overlap? In other words, as we read along the genetic message do we find a base which is a member of two or more codons? It now seems fairly certain that codons do not overlap.

It would appear that the number of nonsense triplets is rather low, since we only occasionally come across them. However this conclusion is less secure than our other deductions about the general nature of the genetic code.

Ribosomes contain RNA, messenger RNA provides the information, transfer RNAs brings the amino acids; so the protein-making machinery is an RNA machinery, completely.

The balance of evidence both from the cell-free system and from the study of mutation, suggests that this does not occur at random, and that triplets coding the same amino acid may well be rather similar.

DNA, like a tape recording, carries a message in which there are specific instructions for a job to be done.

It now seems certain that the amino acid sequence of any protein is determined by the sequence of bases in some region of a particular nucleic acid molecule.

During the decade following the discovery of the double-helical structure of DNA, the problem of translation - namely, how genetic information is used to synthesize proteins - was a central topic in molecular biology.

The genome was once thought to be just the blueprint for a living organism, like a combination of the architect's plan for a building and the builder's list of supplies. It specified the parts, the building blocks, and, somehow, the design of the whole, the way in which they are to be put together.

Genes are like the story, and DNA is the language that the story is written in.

We are beginning to shift into life code. And in the process of shifting into life code, every life form on this planet is coded in a double helix with a sugar phosphate backbone. And that codes whether you become a bacteria, an orange, a lemon, a Lemur, a Cow, a sheep, a human being, a politician, any one of these things is all coded in this four-letter code.

Genes themselves are made of bits.

It seems likely that most if not all the genetic information in any organism is carried by nucleic acid - usually by DNA, although certain small viruses use RNA as their genetic material.

How is the base sequence, divided into codons? There is nothing in the backbone of the nucleic acid, which is perfectly regular, to show us how to group the bases into codons.

I knew the ribosome was going to be the focus of Nobel prizes. It stands at the crossroads of biology, between the gene and what comes out of the gene. But I had convinced myself I was not going to be a winner.

The ribosome is a machine that gets instructions from the genetic code and operates chemically in order to produce the product.

Many ribosomes act simultaneously along the mRNA, forming superstructures called polysomes.

A comparison between the triplets tentatively deduced by these methods with the changes in amino acid sequence produced by mutation shows a fair measure of agreement.

Much of modern molecular biology and microbiology has been based on the effort to decipher the basic code of life, which is made up of four nucleotides: adenine, thymine, cytosine, and guanine.

It has yet to be shown by direct biochemical methods, as opposed to the indirect genetic evidence mentioned earlier, that the code is indeed a triplet code.

Genes are biochemical recipes written in a four-letter alphabet called DNA.

The greatest single achievement of nature to date was surely the invention of the molecule DNA.

All life is nucleic acid; the rest is commentary.