Final answer:
The true statements are that enzymes are biological catalysts, they are composed of proteins, and their activity is contingent upon specific temperature and pH ranges. The statement that enzymes are consumed in reactions is false; they act as catalysts and are not used up in the reaction.
Step-by-step explanation:
Regarding the question which of the following statements about enzymes are true, the correct statements are:
- Enzymes are biological catalysts.
- Enzymes are made up of proteins.
- Enzymes can only function in specific temperature and pH ranges.
The statement that enzymes are consumed during chemical reactions is not true. In fact, enzymes are not consumed; they catalyze reactions and remain unchanged after the reaction is complete.
As biological catalysts, enzymes speed up biochemical reactions by lowering the activation energy required for the reaction. They are typically composed of one or more polypeptide chains, and their structure enables them to bind selectively to specific substrates with an induced fit. This selective binding explains why enzymes are highly specific in their function. Furthermore, the activity of enzymes is influenced by environmental conditions such as temperature and pH. Outside of their optimal range, enzymes may denature and lose their catalytic abilities.