Final answer:
High temperatures can break apart complex molecules and denature proteins, while low temperatures affect membrane fluidity and slow down chemical reactions.
Step-by-step explanation:
Both high and low temperatures can have consequences on the function of macromolecules outside the range of temperatures that an organism is adapted to. High temperatures can cause complex molecules to break apart and proteins to denature, while low temperatures can affect the fluidity of membranes and slow down chemical reactions.
For example, at high temperatures, thermal energy can break apart big molecules into smaller ones, requiring stabilizing molecules with stronger bonds and special proteins. At low temperatures, cell membranes lose fluidity, proteins become too rigid, and chemical reactions slow down.