Question

which of the following defines metabolic pathways?
a) a series of chemical reactions in which mechanical energy converts into chemical energy
b) a series of chemical reactions in which the product of one reaction is the substrate for the next reaction
c) a series of chemical reactions in which organic molecules are broken down to release energy
d) a series of chemical reactions in which light energy converts into chemical energy

Explanation:

Metabolic pathways are a series of chemical reactions where the product of one reaction serves as the substrate for the next reaction. Option A describes energy conversion (mechanical to chemical), which is not the general definition of metabolic pathways. Option C refers to catabolic reactions (breaking down organic molecules for energy), which is a type of metabolic pathway but not the overall definition. Option D is about light - energy conversion (like in photosynthesis), which is also a specific type. Option B correctly captures the essence of a metabolic pathway as a sequential series where the product of one reaction is the substrate for the next.

Answer:

B. a series of chemical reactions in which the product of one reaction is the substrate for the next reaction