2  •  Chemistry 39

Raw materials and fuel for our bodies

Atoms form molecules through bonding. 40

2.1

Everything is made of atoms. 40

2.2

An atom’s electrons determine whether (and how) the atom will bond with other atoms. 43

2.3

Atoms can bond together to form molecules or compounds. 45

Water has features that enable it to support all life. 48

2.4

Hydrogen bonds make water cohesive. 48

2.5

Water has unusual properties that make it critical to life. 49

2.6

Living systems are highly sensitive to acidic and basic conditions. 51

2.7

This is how we do it: Do anti-acid drugs impair digestion and increase the risk of food allergies? 53

Carbohydrates are fuel for living machines. 55

2.8

Carbohydrates include macromolecules that function as fuel. 55

2.9

Glucose provides energy for the body’s cells. 56

2.10

Many complex carbohydrates are time-release packets of energy. 58

2.11

Not all carbohydrates are digestible. 59

Lipids store energy for a rainy day. 61

2.12

Lipids are macromolecules with several functions, including energy storage. 61

2.13

Fats are tasty molecules too plentiful in our diets. 62

2.14

Cholesterol and phospholipids are used to build sex hormones and membranes. 65

Proteins are versatile macromolecules that serve as building blocks. 67

2.15

Proteins are bodybuilding macromolecules. 67

2.16

Proteins are an essential dietary component. 68

2.17

A protein’s function is influenced by its three-dimensional shape. 70

2.18

Enzymes are proteins that speed up chemical reactions. 72

2.19

Enzymes regulate reactions in several ways (but malformed enzymes can cause problems). 73

Nucleic acids store information on how to build and run a body. 75

2.20

Nucleic acids are macromolecules that store information. 75

2.21

DNA holds the genetic information to build an organism. 76

2.22

RNA is a universal translator, reading DNA and directing protein production. 77

StreetBIO: KNOWLEDGE YOU CAN USE

Melt-in-your-mouth chocolate may not be such a sweet idea. 78