AP Biology : 3.4 Cellular Energy - Exam Style questions with Answer- MCQ

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Question

European flycatchers feed caterpillars to their hatchlings. Graph 1 shows the average dates of hatching and fledging (leaving the nest), and the biomass of the caterpillars between early May (when flycatcher young hatch) and June (when fledging of young occurs).

The figure presents two graphs of curves in two coordinate planes. One graph is above the other, and the graphs are related by dates indicated on the horizontal axes. A vertical line runs through the two graphs and is labeled with the date May twenty eighth. The graphs are described as follows. The upper graph consists of curves representing the distribution of flycatcher Hatching and Fledging dates and Hatchling Food Needs over a time period. The horizontal axis has no label, and the dates May fifteenth and June second are indicated along it. The vertical axis is labeled Frequency, and no numbers are indicated along it, although it ends in an arrowhead. The first curve, labeled Date of Hatching, is a bell curve which begins on the horizontal axis to the left of May fifteenth, peaks at May fifteenth, and ends on the horizontal axis to the right of May fifteenth but to the left of May twenty eighth. The second curve, labeled Date of Fledging, is a bell curve which begins on the horizontal axis to the right of May twenty eighth but to the left of June second, peaks at June second at the same height as the first curve, and ends on the horizontal axis to the right of June second. A third bell curve that is broader than the other two curves begins on the horizontal axis immediately before May fifteenth, peaks at May twenty eighth at the same height as the other two curves, and ends on the horizontal axis immediately to the right of June second. This broader curve is labeled Hatchling Food Needs. The lower graph consists of a curve representing the biomass of caterpillars over the same time frame as in the upper graph. The horizontal axis has no label, and the date May twenty eighth is midway along it. The vertical axis is labeled Biomass of Caterpillars, and no numbers are indicated along it, although it ends in an arrowhead. The curve is a bell curve which begins on the horizontal axis immediately before May fifteenth, peaks at May twenty eight, and ends on the horizontal axis at immediately before June second. The curve has approximately the same dimensions as the Hatchling Food Needs curve of the upper graph. The beginning of the curve is labeled Hatching, the peak is labeled Peak Mass, and the end of the curve is labeled Pupae.

Graph 1. Comparison of European flycatcher hatching and fledging dates and caterpillar biomass

Based on the data, scientists claim that the reproductive behavior of European flycatchers is influenced by the availability of energy sources. Which of the following statements best justifies this claim?

A. Young European flycatchers hatch from eggs when caterpillar biomass is available for the young birds to consume and convert into energy for growth.

B. European flycatcher hatchlings begin to need energy to leave the nest only after the caterpillars have turned into pupae.

C. Female European flycatchers require energy to lay eggs, so they lay their eggs when the caterpillar biomass is maximal.

D. The energy requirements for hatching European flycatchers and caterpillars are proportional to each other.

▶️Answer/Explanation

Ans: A
The date of European flycatchers hatching matches the date when the peak biomass of caterpillars is available, ensuring better odds of survival for young flycatchers.

Question

A researcher claims that the incorporation of carbon dioxide into organic molecules during photosynthesis does not violate the second law of thermodynamics.

Which of the following statements best helps justify the researcher’s claim?

A. Organisms contain enzymes that lower the activation energies of specific chemical reactions.

B. An ecosystem is formed by the interaction of a community of organisms with their surrounding environment.

C. Photosynthetic organisms use the organic molecules produced during photosynthesis for growth and repair.

D. The total system that includes photosynthetic organisms and the Sun becomes less ordered over time.

▶️Answer/Explanation

Ans: D
Because the total system that includes photosynthetic organisms and the Sun becomes less ordered over time, the incorporation of carbon dioxide molecules into organic molecules that occurs during photosynthesis does not violate the second law of thermodynamics.

Question

Brown fat is a type of fat tissue found in hibernating mammals. Inside the mitochondria of these fat tissue cells, these mammals have an uncoupling protein embedded in the inner mitochondrial membrane. This uncoupling protein allows hydrogen ions to leak from the intermembrane space back into the mitochondrial matrix. Figure 1 shows details of the processes in the inner mitochondrial membrane.

The figure presents an image of processes that occur across the inner mitochondrial membrane. A cross section of a mitochondrion is shown as well as an enlargement of a boxed region of the Inner Mitochondrial Membrane with the Intermembrane Space on one side and the Mitochondrial Matrix on the other side. One region of the enlargement is labeled Oxidative Phosphorylation. In this region, the Inner Mitochondrial Membrane contains an ATP Synthase enzyme and circles that represent the components of an Electron Transport Chain. Arrows represent the movement of protons (H with a positive charge) from the Mitochondrial Matrix via components of the Electron Transport Chain to the Intermembrane Space. A second arrow represents a proton moving from the Intermembrane Space through the ATP Synthase to the Mitochondrial Matrix. Another arrow touches the end of the ATP Synthase in the Mitochondrial Matrix and indicates the conversion of ADP to ATP. In another region of the enlargement, the Inner Mitochondrial Membrane contains an Uncoupling Protein. An arrow represents a proton moving from the Intermembrane Space through the Uncoupling Protein to the Mitochondrial Matrix. A jagged arrow points from the uncoupling protein to the label Heat in the Mitochondrial Matrix.

Figure 1. Processes in the inner mitochondrial membrane

Which of the following statements provides reasoning that supports the claim that brown fatty tissue keeps an animal warm?

A. The uncoupling protein in this tissue increases the production of $ATP$ and causes more body heat to be produced to warm the animal.

B. The uncoupling protein in this tissue reduces the proton gradient across the membrane and thus produces heat to warm the animal without $ATP$ production.

C. The uncoupling protein in this tissue causes an increase in the proton gradient, which causes more $ATP$ to be produced that helps to warm the animal.

D. The uncoupling protein in this tissue reduces the production of $ATP$ and creates an increase in the proton gradient that allows more heat energy to be produced to warm the animal.

▶️Answer/Explanation

Ans: B
The uncoupling protein causes a reduction in the proton gradient across the inner mitochondrial membrane because protons constantly leak into the matrix. Heat energy is released as the protons move, but less $ATP$ is made because of the decreased concentration of hydrogen ions available to move across $ATP$ synthase.

Question

A researcher claims that the synthesis of $ATP$ from $ADP$ and inorganic phosphate $(P_{i})$ is essential to cellular function.
Which of the following statements best helps justify the researcher’s claim?

A. $ADP$ is a small molecule that some cells release into their environment as a way of communicating with other cells.
B. $ATP$ hydrolysis is an energy-releasing reaction that is often coupled with reactions that require an input of energy.
C. Inorganic phosphate $(P_{i})$ is a substance that cells typically acquire from their environment.
D. $ATP$ synthase is a mitochondrial enzyme that catalyzes the conversion of $ADP$ and \( $P_{i}$ to $ATP$ .

▶️Answer/Explanation

Ans: B
Many cellular processes necessary for maintaining the internal organization of the cell are coupled with the hydrolysis of $ATP$ . Without a supply of $ATP$ , these activities will stop and the cells will die.

Question

A researcher claims that only a portion of the light energy captured by green plants is available for growth and repair.
Which of the following observations best helps justify the researcher’s claim?

A. Light-capturing pigment molecules in green plants absorb red, blue, and violet light but reflect green light.
B. The energy of a photon of light is proportional to its frequency and inversely proportional to its wavelength.
C. As light energy is converted to chemical energy by metabolic processes, some of the energy is lost as heat.
D. Captured energy is stored in the molecular bonds of organic molecules, including simple sugars and starch.

▶️Answer/Explanation

Ans: C
During photosynthesis, some of the captured light energy is lost to the environment in the form of heat energy. As a result, only some of the captured light energy is converted to chemical energy and stored for later use in growth and repair.

AP Biology : 3.4 Cellular Energy – Exam Style questions with Answer- MCQ

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