DNA contains deoxyribose sugar but RNA contains ribose sugar
DNA contains a double strand (double helix) but RNA contains a single strand
DNA contains thymine but RNA contains uracil
What are the two types of RNA?
mRNA - messenger RNA
tRNA - transfer RNA
What are the two stages of protein synthesis?
Transcription - involving mRNA
Translation - involving tRNA
Describe protein synthesis
In the nucleus DNA is unzipped by an enzyme
One section of one strand of DNA is exposed and a molecule of mRNA is transcribed using free nucleotides present in the nucleus. Complementary base pairing (G-C, C-G, A-U, T-A) determines the sequence of the bases on the mRNA molecule. When the mRNA molecule is complete, it leaves the nucleus through the nuclear pores and enters the cytoplasm
In the cytoplasm there are tRNA molecules which bear a triplet (anticodon) of bases corrosponding to a particular amino acid. Each tRNA molecule picks up the appropriate amino acid from the cytoplasm.
The mRNA molecule becomes attached to a ribosome. Its triplet code is read and a tRNA anticodon links with each complementary codon of bases on the mRNA molecule.
Peptide bonds form between adjacent amino acids.
The completed protein is then released into the cytoplasm