The given graph shows the effect of substrate concentration on the rate of reaction of the enzyme green-gram-phosphatase. What does the graph indicate?

Enzymes are proteins. Proteins are long chains of amino acids linked to each other by peptide bonds. Amino acids have many functional groups in their structure. Many of these functional groups are ionisable. As they are weak acids and bases in chemical nature,this ionisation is influenced by the $pH$ of the solution. For many enzymes,activity is influenced by the surrounding $pH$. This is depicted in the curve below. Explain briefly.

At temperatures below the freezing point,an enzyme is .........

Which of the following processes are affected by temperature?

Which enzymes are responsible for changing the arrangement of atoms in substrate molecules?

Which enzyme catalyzes the transfer of a group from one substrate to another?