Final answer:
The barriers to chemical reactions in living cells include low thermal energy within cells, energy required to break bonds, narrow survivable temperature ranges, and the need for energy to initiate reactions. Enzymes help to overcome these barriers by lowering activation energy.
Step-by-step explanation:
The barriers to chemical reactions in living cells are:
- Low thermal energy within cells: Cells typically operate at a temperature that is too low for chemical reactions to occur at a significant rate without assistance.
- The absorption of energy when breaking bonds: Chemical reactions often require energy to break existing bonds, which can be a barrier to the reaction proceeding.
- Narrow temperature range in which cells can survive: Cells can only tolerate a small range of temperatures, limiting the amount of thermal energy available for reactions.
- The need for energy to start a chemical reaction (activation energy): Chemical reactions, both endergonic and exergonic, require energy to overcome an activation barrier before they can proceed.
Enzymes are biological catalysts that help overcome these barriers by lowering the activation energy of reactions, thus increasing reaction rates and allowing cellular processes to occur efficiently under physiological conditions.