Question

Answer these biology-based questions as if a freshman in high school answered them.

Why is enzyme specificity important for maintaining homeostasis in living organisms?

Describe how temperature and pH can affect enzyme activity. Provide an example.

Explain why living organisms need enzymes to survive, even though chemical reactions can occur without them.

How might a mutation in a gene that codes for an enzyme affect an organism?

Why is the shape of an enzyme crucial to its function?

Answer 1

1) Why is enzyme specificity important for maintaining homeostasis in living organisms?
Enzyme specificity means each enzyme only works on certain substrates (like a lock and key). This keeps chemical reactions happening in the right place and at the right time, so cells make or break down the right molecules. If enzymes weren’t specific, unwanted reactions could happen and the cell’s internal balance (homeostasis) would be disrupted.

2) Describe how temperature and pH can affect enzyme activity. Provide an example.
Temperature: Raising temperature usually speeds up enzyme activity to a point, but if it gets too hot the enzyme’s shape changes (denatures) and it stops working. Lower temperatures slow reactions down because molecules move less.
pH: Each enzyme has an optimal pH. Too acidic or too basic conditions change the enzyme’s shape and reduce activity.
Example: Pepsin, a stomach enzyme, works best at very acidic pH (~2). If it were in the neutral pH of the small intestine it would stop working. Human enzymes also work best near body temperature (about 37°C) and can be damaged by fever-level heat.

3) Explain why living organisms need enzymes to survive, even though chemical reactions can occur without them.
Enzymes lower the activation energy of reactions, so reactions happen much faster and at the temperatures cells can tolerate. Without enzymes, many essential reactions would be too slow to support life or would require temperatures that would destroy cells.

4) How might a mutation in a gene that codes for an enzyme affect an organism?
A mutation can change the enzyme’s amino acid sequence, which can change its shape and active site. This can make the enzyme work less well or not at all, causing a buildup or shortage of important molecules. For example, a mutation that reduces lactase production causes lactose intolerance because lactose can’t be broken down properly.

5) Why is the shape of an enzyme crucial to its function?
The shape determines the active site where the substrate fits. If the shape changes, the substrate may not fit and the enzyme can’t do its job. The “lock-and-key” or “induced fit” idea shows that the correct shape is essential for binding and catalysis.