BIOENERGETICS

• What is the primary energy currency that cells use to perform immediate work?

• • A. Glucose (C_6​H_12​O₆​)

• • B. Water (H_2​O)

• • C. Adenosine Triphosphate (ATP)

• • D. Carbon Dioxide (CO_2​)

Answer explanation

• Correct Answer: C.
  The text states, "cells use molecules of ATP as energy currency to perform immediate work."

What is the process that plants use to convert light energy into chemical energy stored in glucose?

• A. Cellular Respiration

• B. Catabolism

• C. Bioenergetics

• D. Photosynthesis

Answer explanation

Correct Answer: D. The text defines photosynthesis as the process where plants "take in energy in the form of light (solar energy) and convert it into chemical energy in the form of glucose."

Which of the following describes an anabolic pathway?

• A. Breaking down complex molecules into simpler ones and releasing energy.

• B. Synthesizing complex molecules from simpler ones, requiring an input of energy.

• C. The breakdown of glucose in the presence of oxygen.

• D. The process of chemiosmosis.

Answer explanation

Correct Answer: B.

The text defines anabolic pathways as those that "require an input of energy to synthesize complex molecules from simpler ones."

Which type of organism performs the majority of global photosynthesis?

• A. Animals

• B. Land plants

• C. Planktonic algae

• D. Fungi

Answer explanation

Correct Answer: C. The text states, "Photosynthesis is the primary pathway in which photosynthetic organisms like plants (the majority of global synthesis is done by planktonic algae) harvest the sun’s energy..."

What substance is a by-product of photosynthesis that is required for cellular respiration in some cells?

• A. Water (H_2​O)

• B. Glucose (C₆​H_12​O₆​)

• C. Oxygen (O₂​)

• D. Carbon Dioxide (CO₂​)

Answer explanation

Correct Answer: C.


The text notes that "The by-product of photosynthesis is oxygen, required by some cells to carry out cellular respiration."

Given the energetic descriptions in the text, which pair correctly matches a metabolic process with its energetic classification?

• A. Cellular Respiration: Anabolic and Endergonic

• B. Photosynthesis: Catabolic and Exergonic

• C. Cellular Respiration: Catabolic and Exergonic

• D. Photosynthesis: Catabolic and Endergonic

Answer explanation

Correct Answer: C. The text states, "Energetically, photosynthesis is anabolic and endergonic, while cellular respiration is catabolic and exergonic."

What is the significance of the fact that all branches of life share some of the same metabolic pathways?

• A. It proves that all modern life forms still rely exclusively on anaerobic metabolism.

• B. It suggests that all organisms evolved from the same ancient common ancestor.

• C. It indicates that the metabolic pathways of eukaryotes and prokaryotes are identical.

• D. It shows that specialized enzymes are not necessary for cellular functions.

Answer explanation

Correct Answer: B.

The text states that researchers have found that all branches of life share some of the same metabolic pathways, "suggesting that all organisms evolved from the same ancient common ancestor."

According to the text, how do the energy requirements for the synthesis of one glucose molecule compare to the energy yield from its breakdown?

• A. Photosynthesis requires 18 ATP and 12 NADPH, while breakdown yields 54 ATP and 12 NADPH.

• B. Photosynthesis requires 54 ATP equivalents, while breakdown yields 36 to 38 ATP molecules.

• C. Both processes require and yield an equal number of ATP molecules to achieve energy balance.

• D. Breakdown requires 18 ATP equivalents, while synthesis yields 36 to 38 ATP molecules.

Answer explanation

• Correct Answer: B.
  
  The text states that "a total of 54 molecule equivalents [18 ATP + 12 NADPH] required for the synthesis of one molecule of glucose." In contrast, the breakdown of one glucose molecule is noted to "store enough energy to make a great deal of ATP, 36 to 38 molecules."

What do the metabolic processes of photosynthesis and cellular respiration have in common, despite their opposite overall chemical formulae?

• A. Both involve the production of CO_2​ and H₂​O.

• B. Both are considered anabolic and endergonic.

• C. Both produce ATP using the same mechanism, chemiosmosis.

• D. Both require a catalyst called ATP.

Answer explanation

Correct Answer:

C. The text points out a key similarity: "One of the most important is that ATP is produced by the same mechanism — chemiosmosis — in both of these metabolic pathways."

The goal of cellular respiration (the breakdown of glucose) is to harvest the energy stored in sugar molecules. How is this harvested energy immediately utilized by the cell?

• A. It is used to create high-energy ATP molecules to perform work.

• B. It is used to synthesize CO₂​ and H₂​O.

• C. It is stored as starch or glycogen for later use.

• D. It is immediately released as heat.

Answer explanation

Correct Answer:
C. The text states the goal of the breakdown of sugar is to harvest energy, which "is used to make high-energy ATP molecules, which can be used to perform work, powering many chemical reactions in the cell."