Chapter 1: The Foundations of Biochemistry

Question 1

What are functional groups in biochemistry?

Answer 1

Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules.

Question 2

What are the three types of isomers in biochemistry?

Answer 2

Geometric isomers: Differ in the arrangement around a double bond (cis vs. trans)
Enantiomers: Mirror-image isomers that are non-superimposable
Diastereomers: Isomers that are not mirror images

Question 3

What is free energy change (delta G), and how does it relate to reaction energetics?

Answer 3

Free energy change (delta G) measures the amount of work a system can perform during a reaction. A negative delta G indicates an exergonic (spontaneous) reaction, while a positive delta G indicates an endergonic (non-spontaneous) reaction

Question 4

How is the standard free energy change (delta Gº) calculated from the equilibrium constant (Keq)?

Answer 4

delta Gº = -RT ln(Keq)

Where:
• R = gas constant (8.314 J/mol·K)
• T = temperature in Kelvin
• Keq = equilibrium constant

Question 5

How can reactions be coupled to allow both energetically favorable and unfavorable reactions to proceed?

Answer 5

Reactions are coupled by combining an exergonic reaction (negative delta G) with an endergonic reaction (positive delta). The overall delta G must be negative for the coupled process to be spontaneous.

Question 6

List the most common functional groups.

Answer 6

hydroxyl (-OH)
carbonyl (-C=O)
carboxyl (-COOH)
amino (-NH2)
phosphate (-PO4)