CHAPTER 2: The Chemistry of Life

BIO 121

Chemistry is relevant…(even if we don’t like it)

Understanding biology is impossible without an introduction to chemistry.

Learning Outcomes

• Explain the chemical nature of biological molecules

• Identify the primary elements in living organisms

• Describe the structure of atoms• Compare and contrast the different types of

bonds• Differentiate between atoms, molecules, and

compounds

Learning Outcomes

• Explain how the structure of water affects its chemical properties

• Explain how acids and bases affect pH• Explain how monomers are used to form

polymers• Compare and contrast the structure and

function of the four classes of biological molecules

2.1 Atoms Make Up All Matter

• Matter– Takes up space

• Energy– Ability to do work

Matter

Elements

All people (and things) are made up of matter

Everything is made up of matter…

• Matter? What’s the matter wit you?– Anything that takes up space and has

mass

• Many different forms of matter:– Rocks– Metals– Oils– Gases

2.1 Atoms Make Up All Matter

• A. Elements Are Fundamental Types of Matter– Element cannot be broken down– Periodic table– Bulk elements

• 25 elements essential to life• Minerals• Trace elements

Figure 2.2 The Periodic Table of Elements.

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H

1

3

11

K

19

37

55

87

4

12

20

38

56

88

21

Y

39

La

57

Ac

89

Ti

22

Zr

40

Hf

72

Rf

104

V

23

Nb

41

Ta

73

Db

105

Cr

24

Mo

42

W

74

Sg

106

Mn

25

Tc

43

Re

75

Bh

107

Fe

26

Ru

44

Os

76

Hs

108

Co

27

Rh

45

Ir

77

Mt

109

Ni

28

Pd

46

Pt

78

Ds

110

Cu

29

Ag

47

Au

79

Rg

111

Zn

30

Cd

48

Hg

80

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112 113 114 115 116

B

5

AI

13

Ga

31

In

49

Tl

81

C

6

Si

14

Ge

32

Sn

50

Pb

82

N

7

P

15

As

33

Sb

51

Bi

83

O

8

S

16

Se

34

Te

52

Po

84

F

9

Cl

17

Br

35

I

53

At

85

He

2

Ne

10

Ar

18

Kr

36

Xe

54

Rn

86

Bulk elements

Trace elementsPossibly essential trace elementsLi

Na

Rb

Cs

Fr

Be

Mg

Ca

Sr

Ba

Ra

Sc

Basic ingredients for all things

Elements

• Fundamental substance• Can’t be broken down into a simpler

substance• Examples include – Carbon, Oxygen,

Hydrogen, Calcium, Gold, Iron, Silver

Image Source:http://education.jlab.org/qa/pen_number.html

Elements essential for life:

• Carbon• Oxygen• Hydrogen• Nitrogen

• Calcium• Phosphorus• Potassium• Sulfur• Sodium• Chlorine• Magnesium

96% of living matter

2.1 Atoms Make Up All Matter

• B. Atoms Are Particles of Elements– Atom

• Protons– Atomic number

• Neutrons• Electrons

Atoms

• Smallest unit of matter that still retains all the properties of an element

• Made up of protons (+), neutrons and electrons (-).

• Neutrons and Protons form atomic nucleus (dense core)

• Electrons form a cloud around the nucleus moving at nearly the speed of light

Image Source: http://www.hk-phy.org/articles/laser/laser_e.html

Figure 2.3 Atom Anatomy.

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Electron (e)

Nucleus

6 protons (p)

6 neutrons (n)

6 total

2.1 Atoms Make Up All Matter

• C. Isotopes Have Different Numbers of Neutrons– Mass number

• Protons plus neutrons

– Isotope• 12C• 13C• 14C• Radioactive

CCarbon

Atomic numberElementSymbol

Atomic mass

6

12.0 112

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Question

• The mass number tells usA. The number of protons onlyB. The number of electrons onlyC. The number of protons and electronsD. The number of protons and neutrons