Question

Suppose that changes to an enzyme that made it work well at high concentrations of the substrate decrease its efficiency when the substrate is at low concentrations (and vice versa). What is the most likely way that an insect could evolve to be able to break down the substrate efficiently at both low and high substrate concentrations?

O Lateral gene transfer
O A gene duplication
O More intense purifying selection
O Muller's ratchet
O An increased point mutation rate

Answer 1

An insect could evolve to break down a substrate efficiently at both low and high substrate concentrations through gene duplication. This allows for the evolution of a new enzyme variant without affecting the original enzyme's function, enabling the organism to handle varying substrate concentrations.

Step-by-step explanation:

Potential Evolutionary Mechanisms for Enzyme Efficiency

To evolve to break down a substrate efficiently at both low and high concentrations, an insect might benefit from a process such as gene duplication. This evolutionary process could allow one copy of the duplicated gene to maintain its original function, while the second copy could accumulate mutations that would permit the enzyme it encodes to function efficiently at a different substrate concentration level. If this new enzyme is beneficial, natural selection could favor these mutant alleles, thus becoming more prevalent in the population over time.

Gene duplication provides a route for metabolic flexibility without compromising the original function of the enzyme, whereas other mechanisms, such as increased point mutation rates or lateral gene transfer, may not specifically target the function in question or may introduce potentially deleterious changes. A mechanism like Muller's ratchet or intense purifying selection is not likely to aid in the evolution of enzyme efficiency across a range of substrate concentrations. On the other hand, purifying selection would tend to remove deleterious mutations and not create new enzyme functionalities.