How Life Works

Contents

Foreword

Preface

Acknowledgements

1 The fantastic nature of matter

The living unit of organisms is the cell

Biology is dependent on chemistry

The Big Bang

What are atoms made of?

Where did atoms other than hydrogen come from?

The structure of atoms

Arrangement of components in atoms

What are molecules?

The chemical properties of the elements are determined by the electrons

2 The problem of how to supply energy to living processes

What do living organisms need energy for?

The universal energy currency unit of all life forms

What makes the structure of ATP so suitable for its central role in all of life?

How is ATP used in the body to drive the synthesis of the large molecules of living matter?

A long research controversy: how is ATP produced in mitochondria?

3 Enzymes overcome the chemical reaction barrier problem

Enzymes bring about all the reactions of life

Enzymes often need a vitamin derivative or a trace metal to function

If the activities of enzymes were not regulated there would be metabolic chaos

Why don’t digestive enzymes digest the body?

4 Proteins: the wonder molecules of life

How can one type of molecule have so many different functions?

A single wrong amino acid out of hundred scan cause a genetic disease

Folding of the proteins

Complex structures of life form from protein molecules by a process of self-assembly

The evolutionary record is written in the amino acid sequence of proteins

5 The genetic problem and DNA

Replication of DNA

6 Deciphering the genetic code

How are amino acids represented by the base sequence of mRNA?

Gene mutations affect the amino acid sequences of proteins, causing genetic diseases

7 The life and death of cells

Strict control of cell multiplication is necessary in animals

Stem cells

Programmed cell death

The human genome project gave startling information about human DNA

8 The origin of life

Where did the first biological molecules come from?

The ancient RNA world

Why has RNA been replaced by DNA in all cellular life?

How were cell membranes formed?

Index