2. why are enzymes necessary in order for chemical reactions to occur in living systems and organisms?

Animal bodies (and even plant bodies for that matter) are complex enough that life couldn't exist without enzymes. enzymes are usually large, complex biological catalysts that are expensive to make. enzymes speed up the rate of chemical reactions without being used up during the reaction (they can be reused many times). they are highly specific in the reactions they regulate. knowing what enzymes are and how they function, why does this explain why complex life forms could not exist if there were no enzymes.

Lactic acid and energy are produced in muscle cells during choose 1 aerobic respiration cellular respiration anaerobic respiration cellular division

What is the similarities and differences between bacteria and eukaryote?