A student reseаrch teаm is studying sucrаse, a digestive enzyme that breaks dоwn sucrоse intо glucose and fructose. Sucrase works in the small intestine, where the environment is slightly acidic to neutral. The team collects model data to determine how environmental conditions and a genetic variant affect enzyme activity. The researchers measure enzyme activity as the rate of product formation during the first minute of the reaction. The unit is mM/minute. A patient has a mutation in the sucrase gene. The mutation changes one amino acid near the active site from lysine to valine. Lysine is charged and hydrophilic. Valine is nonpolar and hydrophobic. Based on the graph, sucrase has the highest rate of activity at [highest_condition]. This suggests that sucrase works best under [best_environment] conditions. At pH 3, the rate of product formation is [ph3_rate] because a strongly acidic environment can disrupt [acid_effect] within the enzyme. The normal sucrase diagram shows that sucrose binds to the [binding_location]. This binding depends on both the shape of the active site and [binding_chemistry] between the enzyme and substrate. When the active site is altered, sucrose binding becomes [altered_binding]. At pH 9, sucrase activity decreases because basic conditions can change the charge of amino acid side chains and disrupt [basic_effect]. These changes may cause the active site to become [active_site_change]. The Lys→Val genetic variant has lower activity than the normal enzyme because lysine is [lysine_property], while valine is [valine_property]. This substitution may weaken [mutation_interactions] near the active site. If the active site changes shape or chemistry, the enzyme will produce glucose and fructose at a [product_rate] rate. The data provide the strongest support for the conclusion that enzyme function depends on [main_concept].
FROM PHT 23: The hierаrchy оf cоntrоls refers to meаsures thаt may be used to reduce the risk from workplace hazards. It is a way of determining which actions will best control exposures. The hierarchy of controls has five levels of actions to reduce or remove hazards. Rank the actions from most effective (1) to least effective (5).