Question

1. people who have alzheimers disease experience an increasing loss of brain function and cognition over time. alzheimers is characterized by a buildup of abnormal protein fragments that damage brain cells. recently scientists have discovered an enzyme, bace2, that decreases these abnormal protein fragments in the brain of a person with alzheimers disease. which statement explains how bace2 most likely works? a) bace2 is a reactant that combines with the abnormal protein fragments b) bace2 molecules link several abnormal protein fragments together forming a complete protein c) bace2 breaks down into smaller pieces that react with the abnormal protein fragments, forming more complex molecules d) bace2 speeds up the reaction that breaks down the abnormal protein fragments 7. fireflies emit light. the production of light by an organism is called bioluminescence. to generate visible light, cells in a fireflys tail produce thousands of luciferase enzymes. luciferase binds to a chemical called luciferin. once bound, the luciferase enzyme speeds up a chemical reaction that combines an oxygen molecule and luciferin to produce oxyluciferin. this reaction requires energy and releases light. which of the following best describes how the luciferase enzyme speeds up the chemical reaction? a) luciferase decreases the temperature of the environment inside the body of the firefly b) luciferase decreases the amount of energy required for the reaction to start c) luciferase increases the amount of time the light is visible d) luciferase increases the number of sites on luciferin that must bind to oxygen 8. lactose is found in milk products. it is converted by the body into a usable form in a species of chemical reactions. the diagram shows the series of reactions that convert lactose into a usable form. if enzyme 2 is denatured, the levels of which substance will increase? a) galactose b) galactose - 1 - phosphate c) lactose d) glucose - 6 - phosphate

Explanation:

1. Enzymes are biological catalysts. BACE2, as an enzyme that decreases abnormal protein fragments in Alzheimer's - it likely speeds up the reaction that breaks down these fragments. Option d is correct as it aligns with the role of an enzyme as a catalyst.
2. Luciferase, as an enzyme, speeds up a chemical reaction by decreasing the activation energy required for the reaction to start. Option b is correct as activation - energy reduction is a common way enzymes catalyze reactions.
3. If Enzyme 2 is denatured, it cannot perform its function of converting galactose to galactose - 1 - phosphate. So, galactose will accumulate. Option a is correct.

Answer:

1. d) BACE2 speeds up the reaction that breaks down the abnormal protein fragments
2. b) Luciferase decreases the amount of energy required for the reaction to start
3. a) Galactose