AP Biology Practice Quiz: Cellular Energy
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Test your understanding with short quizzes. This quiz has 15 questions to check your progress.
Question 1 of 15
All Questions (15)
A) The ability to move
B) A constant input of energy
C) The presence of a cell nucleus
D) A stable, unchanging environment
Correct Answer: B
The text explicitly states, 'All living systems require a constant input of energy to maintain order and power cellular processes.'
A) The sequential nature of energy transfer
B) The common ancestry of all life
C) The requirement of energy input to exceed energy loss
D) The efficiency of single-step energy reactions
Correct Answer: B
The content states that 'Core metabolic pathways, such as glycolysis, are conserved across all recognized domains of life, supporting the concept of common ancestry.'
A) Energy input must be less than energy loss.
B) Energy input must be equal to energy loss.
C) Energy input must exceed energy loss.
D) Energy input is unrelated to energy loss.
Correct Answer: C
The text specifies that 'Life requires a highly ordered system... where energy input must exceed energy loss to maintain order.'
A) To increase the total amount of energy lost as heat
B) To allow for a more controlled and efficient transfer of energy
C) To ensure the pathway is unique to each species
D) To decrease the overall order of the biological system
Correct Answer: B
The provided content directly states that pathways are sequential 'to allow for a more controlled and efficient transfer of energy.'
A) The cell is a closed system that is exempt from the laws of thermodynamics.
B) The cell maintains order by continuously using energy, ensuring its energy input is greater than its energy loss.
C) The cell decreases its internal order to release energy to the environment.
D) The cell achieves order by making energy-related pathways less efficient.
Correct Answer: B
The content states that to maintain order, 'energy input must exceed energy loss.' This constant use of energy allows the cell to overcome the natural tendency towards disorder, in accordance with the laws of thermodynamics.
A) Spontaneous generation
B) Convergent evolution
C) Acquired characteristics
D) Common ancestry
Correct Answer: D
The text directly states that 'shared, conserved processes and features support the concept of common ancestry for all organisms.'
A) Its internal order and organization will decrease.
B) It will evolve new, more efficient metabolic pathways.
C) The efficiency of its energy transfer will spontaneously increase.
D) It will begin to reproduce more rapidly to compensate.
Correct Answer: A
The content specifies that to 'maintain order,' energy input must exceed energy loss. Therefore, if loss exceeds input, the system's high level of order cannot be maintained.
A) Photosynthesis
B) Glycolysis
C) The Krebs Cycle
D) Cellular respiration
Correct Answer: B
The text explicitly names glycolysis: 'Core metabolic pathways, such as glycolysis, are conserved across all recognized domains of life...'
A) this complex, efficient process likely evolved once in a common ancestor.
B) every domain of life independently evolved the exact same sequential pathway.
C) the common ancestor of all life used a much less efficient, single-step process.
D) sequential pathways are a recent evolutionary development.
Correct Answer: A
This question synthesizes the concepts of conserved pathways (glycolysis), sequential structure, and common ancestry. The most logical conclusion is that such a specific and efficient system arose once in a common ancestor and was inherited.
A) Sequential pathways allow cells to defy the laws of thermodynamics by creating new energy.
B) By releasing energy in small, manageable steps, sequential pathways maximize the energy captured and minimize the energy lost, helping to maintain order.
C) Sequential pathways increase the overall energy loss of a system, which is required to power cellular processes.
D) The sequential nature of pathways is unrelated to thermodynamic efficiency and is only a product of common ancestry.
Correct Answer: B
Sequential pathways are for 'controlled and efficient transfer' (Point 5). This efficiency is crucial for ensuring that energy input exceeds energy loss to 'maintain order' (Point 4), a concept rooted in thermodynamics. Releasing energy in small steps minimizes the amount lost as unusable heat.
A) The tendency towards disorder
B) The conservation of metabolic pathways
C) The efficiency of sequential reactions
D) The process of common ancestry
Correct Answer: A
The text links the 'constant input of energy' with the need to 'maintain order.' This implies that energy is used to fight against the natural tendency of systems to become more disordered (increase in entropy), a key concept in thermodynamics.
A) To create new genetic material
B) To eliminate all waste products
C) To power cellular processes and maintain order
D) To decrease the complexity of biological systems
Correct Answer: C
The text states that a constant input of energy is required 'to maintain order and power cellular processes.'
A) is a closed system that does not exchange energy with its surroundings.
B) has an energy input from photosynthesis that exceeds the energy it loses through metabolic processes.
C) has stopped all cellular processes to conserve its ordered state.
D) violates the second law of thermodynamics to maintain its structure.
Correct Answer: B
This question applies the abstract principle to a concrete example. To maintain its 'highly ordered system,' the tree must have an 'energy input' (photosynthesis) that 'must exceed energy loss' (respiration, heat loss), as stated in the content.
A) Sequential pathways eliminate the need for a constant energy input.
B) Sequential pathways make energy transfer less efficient, thus increasing the total energy required.
C) By efficiently managing energy transfer, sequential pathways help the cell make the most of its constant energy input.
D) The constant energy requirement is only necessary for non-sequential pathways.
Correct Answer: C
Living systems need a constant input of energy. Sequential pathways are structured for efficient transfer. Therefore, the efficient structure helps the system effectively utilize the constant energy it must acquire to maintain order.
A) Life requires a constant input of energy to maintain order, and the conservation of efficient, sequential energy pathways like glycolysis across all domains provides strong evidence for a common ancestor that solved this fundamental problem.
B) The laws of thermodynamics dictate that all systems must become more disordered, proving that the concept of common ancestry is flawed because life has become more complex over time.
C) All living systems require energy, but because energy pathways are so different across species, there is little evidence to support common ancestry.
D) Sequential pathways evolved to make energy transfer less efficient, forcing organisms to constantly seek more energy and driving the evolution of new species.
Correct Answer: A
This option correctly combines the key concepts: the need for energy to maintain order (Points 1, 3, 4), the structure of pathways for efficiency (Point 5), and the use of conserved pathways (glycolysis) as evidence for common ancestry (Points 2, 6).