$${C_{12}}{H_{22}}{O_{11}} + {H_2}O\buildrel {Enzyme\,A} \over \longrightarrow \mathop {{C_6}{H_{12}}{O_6}}\limits_{Glu\cos e} + \mathop {{C_6}{H_{12}}{O_6}}\limits_{Fructose} $$

$$\mathop {{C_6}{H_{12}}{O_6}}\limits_{Glu\cos e} \buildrel {Enzyme\,B} \over \longrightarrow 2{C_2}{H_5}OH + 2C{O_2}$$

In the above reactions, the enzyme A and enzyme B respectively are :

Fructose is an example of :

Which of the following is correct structure of tyrosine?

The secondary structure of protein is stabilised by: