Iron is present in which one of the following?

Which of the following is a loosely bound coenzyme?

What are the co-factors called that are loosely bound to enzymes?

Which of the following enzymes are activated in the presence of $Mg^{++}$?
$(A)$ Pyruvate dehydrogenase
$(B)$ $DNA$ polymerase
$(C)$ Hexokinase
$(D)$ Rubisco
$(E)$ Catalase
$(F)$ $PEP$ carboxylase
$(G)$ Amylase
Options:
$(a)$ $B, C, D, E$
$(b)$ $A, F, C, D$
$(c)$ $G, F, B, E$
$(d)$ $A, F, C, B$

Organic compounds bound to an enzyme,which are essential for its catalytic activity,are called .........

Assertion $(A)$: The structure of an enzyme consists of an apoenzyme and a coenzyme.
Reason $(R)$: $A$ coenzyme is a non-protein part that makes the enzyme active.