Question 1

Which of the following statements best explains why carbon is the chemical foundation of life rather than silicon?

Accepted Answer

Carbon-to-carbon bonds are stronger and more stable than silicon-to-silicon bonds, allowing for more complex and durable biomolecules.

Question 2

A researcher synthesizes a drug with two chiral centers. Which of the following is most likely to occur regarding its biological activity?

Accepted Answer

Different stereoisomers may have distinct biological activities, with some potentially causing harmful effects.

Question 3

Which functional group is most likely to exist in different protonation states depending on pH, affecting the properties of biomolecules?

Accepted Answer

Carboxyl group

Question 4

Which of the following best describes the difference between conformation and configuration in biomolecules?

Accepted Answer

Configuration refers to the fixed spatial arrangement of atoms (due to double bonds or chiral centers), while conformation is the flexible arrangement that can change without breaking covalent bonds.

Question 5

Which equation correctly represents the relationship between Gibbs free energy, enthalpy, entropy, and temperature?

Accepted Answer

$G = H - TS$

Question 6

A reaction in a cell has $\Delta G = +5$ kJ/mol. What does this indicate about the reaction?

Accepted Answer

The reaction is endergonic and requires input of free energy to proceed.

Question 7

Which of the following is a major advantage of constructing biomolecules as polymers from simple building blocks?

Accepted Answer

It allows for simple and conserved reactions for synthesis and degradation, recycling, and generation of molecular diversity.

Question 8

Which statement best describes the central dogma of biochemistry?

Accepted Answer

Genetic information flows from DNA to RNA to protein.

Question 9

Which of the following is NOT a correct comparison between prokaryotic and eukaryotic cells?

Accepted Answer

Prokaryotes are generally larger and more complex than eukaryotes.

Question 10

Which of the following best explains why experiments performed in vitro may not always reflect in vivo biological processes?

Accepted Answer

In vitro experiments lack the complex, organized interactions present within living cells and organisms.

Question 11

Which of the following is a correct statement about the four major classes of biomolecules?

Accepted Answer

Proteins are linear polymers of amino acids.

Question 12

A mutation causes a change in the DNA sequence of a gene. Which of the following is the most direct consequence?

Accepted Answer

The structure and function of the corresponding protein may change.

Question 13

Which of the following statements about ATP is correct?

Accepted Answer

ATP serves as a common energy currency, linking catabolic and anabolic reactions.

Question 14

Which of the following best describes the role of entropy in the second law of thermodynamics as it applies to living systems?

Accepted Answer

Living systems increase the total entropy of the universe while maintaining local organization.

Question 15

Which of the following is a real-world example of the importance of stereochemistry in biochemistry?

Accepted Answer

The use of thalidomide, where one stereoisomer caused birth defects while the other did not.

Question 16

Which of the following statements about the genetic basis of living organisms is correct?

Accepted Answer

DNA provides instructions for forming all cellular components and serves as a template for its own replication.

Question 17

Which of the following is a correct application of energy coupling in biological reactions?

Accepted Answer

An endergonic reaction is driven by coupling it to an exergonic reaction so that the overall $\Delta G$ is negative.

Question 18

Which of the following elements is most limiting for plant growth and food production due to its availability in the biosphere?

Accepted Answer

Nitrogen

Question 19

Which of the following best illustrates the concept of the 'Ship of Theseus' in the context of molecular biology?

Accepted Answer

The constant turnover and replacement of molecules within an organism raises questions about identity over time.

Module 1: Biochemistry and the Unity of Life – Foundations for Anatomy & Physiology

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