Question

marissa is investigating a biochemical reaction involving carbon compounds. the reaction requires a specific enzyme. what is the role of the enzyme in this reaction?
to determine whether the reaction proceeds in the forward or reverse direction
to absorb the energy released by the reaction
to lengthen the carbon chain of each compound
to speed up the chemical reaction
to increase the activation energy of the reaction
what is the effect of an enzyme on the energy of a chemical reaction?
enzymes increase the free energy of the products.
enzymes decrease the activation energy of the reaction.
enzymes decrease the free energy of the reactants.
enzymes decrease the difference in energy between products and reactants.
glucose is an example of a
polysaccharide
disaccharide
monosaccharide

Explanation:

• Enzymes are biological catalysts. Catalysts speed up chemical reactions by lowering the activation energy. They do not determine the direction of a reaction (thermodynamics does that), absorb energy released (enzymes don't absorb reaction - released energy in this context), lengthen carbon chains (not a general role of enzymes in all reactions), or increase activation energy (they lower it). So for the first question, the role of the enzyme is to speed up the chemical reaction.
• Enzymes lower the activation energy of a reaction. They do not change the free energy of products or reactants (that is determined by the nature of the substances and the reaction conditions). The difference in energy between products and reactants (ΔG) is also not changed by enzymes (it is a thermodynamic property). So for the second question, enzymes decrease the activation energy of the reaction.
• Glucose is a simple sugar. Polysaccharides are long - chain carbohydrates (e.g., starch, cellulose). Disaccharides are made of two monosaccharides (e.g., sucrose = glucose + fructose). A monosaccharide is the simplest form of a carbohydrate, and glucose is a monosaccharide.

Answer:

• First question: to speed up the chemical reaction
• Second question: Enzymes decrease the activation energy of the reaction
• Third question: monosaccharide