Year 12s: what will be the first way you research your future options? >>

Confused .. Need help

(edited 7 years ago)

The information is stored as the specific order of bases in DNA. Of course, information is useless unless you can get at it, which is where we get to the special properties of nucleic acids - complimentary base pairing. The DNA sequence is stored as two complimentary strands, so it is possible to pull the double helix apart and be left with two single strands; because the strands match or compliment each other, you can rebuild the complimentary sequence out of fresh nucleotides (the individual building blocks of DNA). If you do this on both strands, you end up with two duplicate copies of the DNA molecule, a process called replication.

In terms of doing something useful with genetic information, a similar process is used - part of the strand is pulled apart, and using that sequence matching of complimentary base pairing, the sequence is "copied" into a new strand - this time made out of RNA rather than DNA. This process is used to copy small, useful chunks of information - individual genes - off the very long DNA molecule, which may contain lots of genes. The RNA copy is called a "messenger RNA transcript".

The transcript is then fed through a large protein called a ribosome, which examines the mRNA a little bit at a time. The coded information on the mRNA transcript - in the form of a sequence of RNA nucleotides - is translated into a sequence of amino acids, the primary sequence of the protein coded by the gene.

The primary sequence of amino acids defines the shape that the finished protein takes. That shape defines the behaviour and function of the protein. The specific combination of proteins produced by a cell defines pretty much everything about it's shape, appearance, and how it behaves in response to its environment. In this way, the information stored as DNA gets turned into the function of the cell - DNA sequence is copied into mRNA sequence (transcription) which is converted into amino acid sequence (translation), which defines the protein shape, which defines protein behaviour, which defines cell behaviour. Bear in mind that each cell produces many thousands of different kinds of proteins (including proteins for deciding which proteins to make!) which all work together to make the cell function as a whole.

Quick Reply

Related discussions

Latest

Articles for you

Struggling at school? Five reasons not to worry

63 things students wish they had known about university

Edexcel A-Level Economics Paper 1 - Unofficial Mark Scheme - 18 May 2023

Should you choose a campus or city university?