Energy is required for reactions (synthesis of complex molecules).
Energy is required for reactions (synthesis of complex molecules).
Energy is needed for active transport across membranes.
Mechanical work, such as muscle contraction and flagellar movement, requires energy.
Maintaining body temperature (in endotherms) and generating electrical impulses also consume energy.
Examiner Tip
When asked to 'outline' or 'explain' the need for energy, provide specific examples of cellular processes that directly consume ATP.
The total energy expenditure of an organism is known as its metabolic rate, which can vary significantly based on activity level, age, and environmental factors.
