How many hydrogen bonds form when adenine and cytosine each bind to their complementary bases?

6.2.1 state that a polypeptide is coded for by a gene and that a gene is a sequence of nucleotides that forms part of a DNA molecule

6.2.2 describe the principle of the universal genetic code in which different triplets of DNA bases either code for specific amino acids or correspond to start and stop codons

6.2.3.1 RNA polymerase

6.2.3.2 messenger RNA (mRNA)

6.2.3.3 codons

6.2.3.4 transfer RNA (tRNA)

6.2.3.5 anticodons

6.2.3.6 ribosomes

6.2.4 state that the strand of a DNA molecule that is used in transcription is called the transcribed or template strand and that the other strand is called the non-transcribed strand

6.2.5 explain that, in eukaryotes, the RNA molecule formed following transcription (primary transcript) is modified by the removal of non-coding sequences (introns) and the joining together of coding sequences (exons) to form mRNA

6.2.6 state that a gene mutation is a change in the sequence of base pairs in a DNA molecule that may result in an altered polypeptide

6.2.7 explain that a gene mutation is a result of substitution or deletion or insertion of nucleotides in DNA and outline how each of these types of mutation may affect the polypeptide produced