Question

1. how do enzymes function in chemical reactions? a. they completely change the reactants b. they slow down the reaction process c. they speed up reactions by lowering activation energy d. they require no conditions to function 1. what is a metabolic pathway? a. a series of unrelated reactions b. a series of enzymes helping to build or break down molecules c. a single reaction in isolation d. a pathway for energy storage 1. which of the following statements is true regarding cells? a. cells never die b. dead cells are replaced constantly c. cells do not need energy to function d. cells only perform one type of chemical reaction

Explanation:

• First question: Enzymes are biological catalysts. Catalysts speed up reactions by lowering the activation energy (the energy required to start a reaction). They don't change the reactants (a is wrong), they speed up not slow down reactions (b is wrong), and they do require certain conditions (like proper temperature and pH, so d is wrong).
• Second question: A metabolic pathway is a series of enzyme - catalyzed reactions. Enzymes in these pathways help build (anabolic) or break down (catabolic) molecules. It's not a series of unrelated reactions (a is wrong), not a single reaction (c is wrong), and not specifically just for energy storage (d is wrong as it's more about the series of reactions with enzymes).
• Third question: Cells do die (a is wrong). Cells need energy (usually in the form of ATP) to function (c is wrong). Cells perform multiple chemical reactions (d is wrong). Dead cells (like skin cells) are constantly replaced.

Answer:

1. c. They speed up reactions by lowering activation energy
2. b. A series of enzymes helping to build or break down molecules
3. b. Dead cells are replaced constantly