cytosine and adenine

cytosine and guanine

cytosine and thymine

cytosine and uracil

$$C_5^{'}$$ and $$C_2^{'}$$ respectively of the sugar molecule

$$C_2^{'}$$ and $$C_5^{'}$$ respectively of the sugar molecule

$$C_1^{'}$$ and $$C_5^{'}$$ respectively of the sugar molecule

$$C_5^{'}$$ and $$C_1^{'}$$ respectively of the sugar molecule

Enzymes are specific biological catalysts that can normally function at very high temperature (T ~ 1000 K)

Enzymes are specific biological catalysts that the posses well – defined active sites

Enzymes are specific biological catalysts that can not be poisoned

Enzymes are normally heterogeneous catalysts that are very specific in their action

Uracil

Thymine

Guanine

Cytosine