Making+Proteins

Making Proteins (Q 13-18) Read page 192-3 ( Section 11.3 ).
 * __Making proteins__ **

DNA strand carry instructions in the form of a three letter 'code words' which are called triplets. They are made up of three bases.

Triplets provide coding for different amino acids. In genetic coding, triplets are the ordering of nucleotides in DNA molecules that carry the genetic information in living cells.

DNA does not necessarily leave the nucleus in its original form. A process called Transcription (cross writing), transcribes a base sequence in the DNA into another base sequence, mRNA (messenger RNA). Once mRNA has been made, it leaves the Nucleus, and travels to ribosomes. mRNA passes the code from the nucleus to the ribosomes.

The message on the DNA is copied onto RNA (mRNA). The mRNA leaves the nucleus and goes to a ribosome. Inside the ribosome the message on the mRNA is read and a protein  is built. 

(17) Copy the diagram on the top half of page 193 (end of Section 11.3 )



It only takes about 10 seconds for a ribosome to build up a molecule of haemoglobin (containing over 600 amino acids) so it is an extremely rapid process. The protein haemoglobin gives the characteristic of oxygen transport to red blood cells.

Here is a good video describing the process: [] DNA Transcription Process Animation