Outline, using a simple model, the process by which DNA controls the production of polypeptides.
Polypeptide synthesis involves a type of nucleic acid, called RNA (ribonucleic acid). RNA is the intermediary between DNA and polypeptide synthesis. It is a single strand of nucleotide bases. It has ribose sugar and the nitrogen base, thymine, is replaced by uracil which bonds with adenine.
There are two types of RNA that are involved in polypeptide synthesis, messenger RNA (mRNA) and transfer RNA (tRNA).
In the nucleus, the double stranded DNA molecules unzip and the DNA code is transcribed into the single stranded mRNA molecule. The mRNA moves out of the nucleus into the cytoplasm and attaches to a ribosome. In the cytoplasm, the mRNA is translated into amino acids.
At the ribosome, the messenger RNA lines up forming a template. A group of three bases, called a codon, codes for a specific amino acid. There are codes that start and stop the chain formation. AUG is the starting point for translation.
tRNA has an anticodon (a non-amino acid forming codon) on one end and an amino acid on the other. A polypeptide is formed as each amino acid is added from tRNA to a chain following the sequence on the mRNA.
Perform a first-hand investigation or process information from secondary sources to develop a simple model for polypeptide synthesis.
You could choose to perform a first hand investigation using beads and plasticine to model illustrate polypeptide synthesis. Include in your model the transfer of information from DNA.
These are from the Charles Sturt University notes on Blueprint Of Life.
