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Nombre de programmes trouvés : 267
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le (5m49s)

1.4. What is an algorithm?

We have seen that a genomic textcan be indeed a very long sequence of characters. And to interpret this sequence of characters, we will need to use computers. Using computers means writing program. Writing program means designing first algorithm. So, let's see what an algorithm is. An algorithm is a series of operationsto be executed by a computer, but maybe also executed by ahuman, for solving a problem.  In the first algorithm we will study in this session and next one, the problem will be to count the number of different of the four different nucleotides which appeared in the sequence. It's a sequence of operations. You may say that in ...
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le (7m33s)

Biotechnologies au service du climat - P. Monsan, INSA

À l’occasion de l’Exposition universelle de Milan en 2015, 24 experts ont fait le point sur l’état des connaissances scientifiques dans différents domaines portant sur l’environnement, l’agriculture et l’alimentation, dans la perspective d’une alimentation durable à l’échelle mondiale. Ces conférences, d’une durée de 10 à 15 minutes, permettent d’avoir une vision d’ensemble des enjeux actuels qui mobilisent la recherche agronomique et vétérinaire.
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le (4m53s)

1.2. At the heart of the cell: the DNA macromolecule

During the last session, we saw how at the heart of the cell there's DNA in the nucleus, sometimes of cells, or directly in the cytoplasm of the bacteria. The DNA is what we call a macromolecule, that is a very long molecule. It's Avery, in 1944, who discovered that the DNA was the support of genetic information. But the scientists who are most well-known for DNA are Francis Crick and James Watson who discovered together, with Maurice Wilkins and Rosalind Franklin, in 1953, the structure of DNA, the famous double helix, the two strands. Here are Crick and Watson explaining on a very crude wire model far away ...
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le (7m22s)

1.3. DNA codes for genetic information

Remember at the heart of any cell,there is this very long molecule which is called a macromolecule for this reason, which is the DNA molecule. Now we will see that DNA molecules support what is called the "genetic information". So, DNAcodes for genetic information. How? If you consider this doublestrand molecule, DNA molecule, you remember that on each strandof the molecule, there is a succession of nucleotides. You can follow these nucleotides and write their name or moreexactly the initial of their name. And you will get what we call the sequence". Look: C, T, A and so on. The process by which you obtain this sequence of characters of ...
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le (5m11s)

1.5. Counting nucleotides

In this session, don't panic. We will design our first algorithm. This algorithm is forcounting nucleotides. The idea here is that as an input,you have a sequence of nucleotides, of bases, of letters, of characters which ends with a star symbol, here. And, you want to count the number of A,C, G and T, and then the frequencies. To write an algorithm in thispseudo code language, you need first to declare on which objector variables you will work. Here, we declare severalinteger variables. What does it mean integer variables? That is a variable, the value of which can be an integer: 1, 2, 3, minus 9 and so on. So, integer ...
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le (4m29s)

1.6. GC and AT contents of DNA sequence

We have designed our first algorithmfor counting nucleotides. Remember, what we have writtenin pseudo code is first declaration of variables. We have several integer variables that are variables which cantake as a value an integer. One, two, three minus five and so on. We have the sequence of characters we want to interpret, declare as a character string oflengths and define. Then we have the initializationof our different variables. This symbol is a symbol for assignment, it means that zero becomes the value of total nb, nbT and soon and so on and here we say: index takes the value one. It means that we position at the beginning of ...
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