In Humans the Nucleus contains 46 chromosomes (23 Pairs).
A DNA Molecule is in the shape of a Double Helix
DNA is made up of 4 bases each with a complimentary pairing to each other. Adenine links with Thymine and Cytosine links to Guanine.
The two strands are held together by hydrogen bonds between complementary base pairs.
Genes are the basic units of heredity and are located on chromosomes.
mRNA exists as a single stranded molecule until it is translated into a Polypeptide because it is complementary to the sequence of amino acids on the Ribosome. This is because DNA is to large leave the Nucleus and fit into the Ribosome.
Protein Synthesis occurs at ribosomes which are found in the cytoplasm.