Chapter 14, Problem 22A

Summary Introduction

Introduction:

Scientists Stanley miller and Harold Urey were the first to show that simple organic molecules could be made from inorganic compounds. Many experiments were conducted under conditions that were similar to atmosphere of early Earth. The final reaction products in these experiments were amino acids and sugars as well as nucleotides.

Answer to Problem 22A

Correct answer:

The correct answer is option C. providing a framework for amino acid chains

Explanation of Solution

Explanation/justification for the correct answer:

Option C. providing a framework for amino acid chains − Wherever the first organic molecules originated, it was clear that the next important step would be the formation of proteins. Amino acids alone cannot produce life. Life requires proteins which are chains of amino acids. Amino acids could bind to one another but they would easily separate too. One mechanism for formation of proteins would be if amino acids were bound by clay particles. Clay could provide a framework for protein assembly.

Hence this is the correct option.

Explanation for incorrect answer:

Option A. producing the first oxygen in the atmosphere −The cyanobacteria are primitive prokaryotes that are found in rocks as old as 3.5 billion years. They produced the first oxygen in the atmosphere. The clay particles could provide a framework for amino acids to form proteins.

Hence this is not the correct option.

Option B. forming the first plasma membranes- The clay particles could provide a framework for amino acids to form proteins. They did not form the first plasma membranes. Hence this is not the correct option.

Option D. capturing prokaryotes for chloroplast evolution − The clay particles could provide a framework for amino acids to form proteins. They did not capture prokaryotes for chloroplast evolution. Hence this is not the correct option.