Chapter 2, Problem 16Q

A. (a)

Summary Introduction

To determine: How many different molecules that are composed of two amino acids and are linked together by peptide bonds can be made from 20 naturally occurring amino acids.

Introduction: Proteins are made up of amino acids. Twenty-two amino acids are naturally incorporated into polypeptides and are called natural or proteogenic amino acids. Out of these, 20 amino acids are encoded by the genetic code.

(b)

Summary Introduction

To determine: How many different molecules that are composed of three amino acids and are linked together by peptide bonds can be made from 20 naturally occurring amino acids.

Introduction: Proteins are made up of amino acids. Twenty-two amino acids are naturally incorporated into polypeptides and are called natural or proteogenic amino acids. Out of these, 20 amino acids are encoded by the genetic code.

(c)

Summary Introduction

To determine: How many different molecules that are composed of four amino acids and are linked together by peptide bonds can be made from 20 naturally occurring amino acids.

Introduction: Proteins are made up of amino acids. Twenty-two amino acids are naturally incorporated into polypeptides and are called natural or proteogenic amino acids. Out of these, 20 amino acids are encoded by the genetic code.

B1.

Summary Introduction

To calculate: The weight of a given mixture consisting of one molecule each of all possible sequences of a small protein of molecular weight 4800 Daltons, if the average molecular weight of an aminoacid is given as 120 Daltons.

Introduction: Amino acids are organic compounds containing amine and carboxyl functional groups, along with a side chain (R group) specific to each amino acid. The average molecular weight of an amino acid is 110Da.

B2.

Summary Introduction

To explain: What size of the container is needed to hold the given sample.

Introduction: Amino acids are organic compounds containing amine and carboxyl functional groups, along with a side chain (R group) specific to each amino acid. The average molecular weight of an amino acid is 110Da.

C.

Summary Introduction

To explain: What does the above calculation tell about the fraction of possible proteins that are currently in use by living organisms if the average molecular weight of the protein is about 30,000 Daltons.

Introduction: Proteins are made up of amino acids. Twenty-two amino acids are naturally incorporated into polypeptides and are called natural or proteogenic amino acids. Out of these, 20 amino acids are encoded by the genetic code.