The document provides an overview of key concepts in introductory biology and chemistry. It covers the structure and properties of the four main macromolecules that make up living things: carbohydrates, lipids, proteins, and nucleic acids. For each topic, it defines important terms and concepts, describes the structure and functions of the macromolecule, and provides take-home messages that summarize the key learning points. The level of detail and examples included make it suitable as course material for an introductory biology or chemistry class.

1. Chemistry
BIOL 108
Intro to Bio Sci
Chapter 2
Rob Swatski
Assoc Prof Biology
HACC-York1

2. Learning Goals
Describe what
atoms are,
their structure,
& how they
bond.
Understand
water’s
features that
help it support
all life.
Describe the
structure &
function of
carbohydrates.
Describe the
structure &
function of
lipids.
Describe the
structure &
function of
proteins.
Describe the
structure &
function of
nucleic acids.
2

3. 3

4. 2.1–2.3
Atoms form
molecules through
bonding.
4

5. 2.1 Everything is
made of atoms.
An element is a
substance that cannot
be broken down
chemically into any
other substances.
An atom is a bit of
matter that cannot be
subdivided any further
without losing its
essential properties.
5

6. 6

7. Insert new figure 2.3
7

8. Radioactive Atoms
 A few atomic nuclei are not stable and break
down spontaneously.
 These atoms are radioactive.
 They release, at a constant rate, a tiny, high-
speed particle carrying a lot of energy.
8

9. insert new fig 2.4
9

10. 10

11. Take-Home Message 2.1
Everything around us,
living or not, is made
from atoms, the
smallest unit into which
material can be divided.
Atoms all have the same
general structure.
They are made up of
protons and neutrons in
the nucleus and
electrons, which circle
far around the nucleus.
11

12. 2.2 An atom’s
electrons
determine how
(and whether)
the atom will
bond with other
atoms.
12

13. Insert new fig 2-6
13

14. Insert fig 2-7
14

15. Insert new fig 2-8
15

16. Take-Home Message 2.2
The chemical
characteristics of an
atom depend upon
number of electrons in
their outermost shells.
Atoms are most stable
and least likely to bond
with other atoms when
their outermost
electron shell is full.
16

17. 2.3 Atoms can bond
together to form
molecules or
compounds.
17

18. 18

19. 19

20. Molecules = Products of Bonding
20

21. 21

22. 22

23. Insert fig 2-11
23

24. Insert fig 2-12
24

25. Take-Home Message 2.3
Atoms can be bound
together in three different
ways.
Covalent bonds, in which
atoms share electrons, are
the strongest.
In ionic bonds, the next
strongest, one atom transfers
its electrons to another and
the two oppositely charged
ions are attracted to each
other, forming a compound.
Hydrogen bonds, the
weakest, involve the
attraction between a
hydrogen atom and another
polar atom or molecule.
25

26. 26

27. 2.4 Hydrogen bonds make water cohesive.
27

28. 28

29. Take-Home Message 2.4
Water molecules easily
form hydrogen bonds,
giving water great
cohesiveness.
29

30. 2.5 Water has unusual
properties that make it
critical to life.
Cohesion
Large heat
capacity
Low density as a
solid
Good solvent
30

31. 31
Cohesion
How?

32. 32

33. 33

34. 34

35. 35

36. Take-Home Message 2.5
The hydrogen bonds between
water molecules give water
several of its most important
characteristics: cohesiveness,
low density as a solid, the ability
to resist temperature changes, &
broad effectiveness as a solvent
36

37. 2.6 Living systems are highly sensitive
to acidic and basic conditions.
37

38. Hydrogen Ions & Hydroxide Ions
Ionized Hydroxide
Molecule
OH-
Non-Ionized Water
Molecule
H2O
O O
H H H
38

39. pH Scale
The amount of H+
in a solution is a
measure of its
acidity & is called
pH.
Acids
Bases
39
Acidic
[H+] > [OH–]
Neutral
[H+] = [OH–]
Basic
[H+] < [OH–]
7
0
14

40. 40

41. H+ Ions & Acids
H+ very reactive
Acids can
donate H+ to
other chemicals
41

42. Bases
Low H+ & high
OH-
Antacids, baking
soda, milk of
magnesia
42

43. Buffers
Can quickly absorb
excess H+ ions to keep
a solution from
becoming too acidic
Can also quickly
release H+ ions to
counteract any
increases in OH-
concentration
43

44. Take-Home Message 2.6
The pH of a fluid is a
measure of how acidic or
basic a solution is and
depends on the
concentration of dissolved
H+ ions present.
Acids, such as vinegar, can
donate protons to other
chemicals while bases,
including baking soda, bind
with free protons.
44

45. 45

46. 2.7 Carbohydrates are macromolecules that
function as fuel.
46

47. Four Types of Macromolecules
Carbohydrates Lipids Proteins Nucleic Acids
47

48. Carbohydrates
C, H, and O
Primary fuel
for organisms
Cell structure
48

49. Take-Home Message 2.7
Carbohydrates are the
primary fuel for running all
cellular machinery and also
form much of the structure
of cells in all life forms.
Carbohydrates contain
carbon, hydrogen, and
oxygen, and generally have
the same number of carbon
atoms as they do H2O units.
The C-H bonds of
carbohydrates store a great
deal of energy and are
easily broken by organisms.
49

50. 2.8 Simple sugars are the
most effective source of
energy.
Monosaccharides
3-7 carbon atoms
Glucose &
fructose
50

51. Glucose
Most carbohydrates
are ultimately
converted into
glucose
Glucose provides
energy for the
body’s cells
Stored temporarily
as glycogen
51

52. What is “carbo-loading”?
52

53. 53

54. Take-Home Message 2.8
The simplest carbohydrates
are called monosaccharides
or simple sugars. They
contain from 3-7 carbon
atoms.
The sugar glucose is the most
important carbohydrate to
living organisms.
Glucose in the bloodstream
can be used as an energy
source, can be stored as
glycogen in the muscles
and liver for later use, or
can be converted to fat.
54

55. 2.9 Complex
carbohydrates are
time-released packets
of energy.
More than 1
sugar unit:
monosaccharide
Disaccharides:
sucrose, lactose
Polysaccharides:
starch, cellulose
55

56. Starch
100’s of glucose
molecules
joined together
Barley, wheat,
rye, corn, & rice
Glycogen:
“animal starch”
56

57. 57

58. Take-Home Message 2. 9
Multiple simple
carbohydrates sometimes
link together into more
complex carbohydrates.
Types of complex
carbohydrates include starch,
the primary form of energy
storage in plants, and
glycogen, a primary form of
energy storage in animals.
58

59. 2.10 Not all
carbohydrates
are digestible.
Cellulose
Chitin
59

60. 60

61. Fiber
“Roughage”
Colon cancer
prevention &
reduction
Termites
ecological
role
61

62. Take-Home Message 2.10
Some complex
carbohydrates, including
chitin and cellulose,
cannot be digested by
most animals.
Such indigestible
carbohydrates in the diet,
called fiber, aid in
digestion and have
numerous health benefits.
62

63. 2.11–2.13
Lipids store
energy for a rainy
day.
63

64. 2.11 Lipids are macromolecules with several functions,
including energy storage.
64

65. Why does a salad
dressing made with
vinegar and oil
separate into two
layers shortly after
you shake it?
Hydrophilic
Hydrophobic
65

66. Take-Home Message 2.11
Lipids are non-soluble in
water and greasy to the
touch.
They are valuable to
organisms in long-term
energy storage and
insulation, membrane
formation, and as
hormones.
66

67. 2.12 Fats are tasty
molecules too
plentiful in our diets.
Glycerol:
“head”
region
Fatty acid
“tails”
Triglycerides
67

68. 68

69. 69

70. Saturated &
Unsaturated
Fats
# of bonds in the
hydrocarbon chain
in a fatty acid
Health
considerations
70

71. 71

72. 72

73. 73

74. 74
Carotid artery
plaque

75. Take-Home Message 2.12
Fats, including the triglycerides
common in the food we eat, are
one type of lipid.
Characterized by long
hydrocarbon tails, fats effectively
store energy in the bonds
connecting the molecules.
Their caloric density is
responsible for humans’
preferring fats to other
macromolecules in the diet, and
is also responsible for their
association with obesity and
illness in the modern world.
75

76. 2.13 Cholesterol
and phospholipids
are used to build
sex hormones and
membranes.
Not all lipids
are fats
Sterols
76

77. 77

78. Cholesterol
Important
component of most
cell membranes.
Can attach to blood
vessel walls and
cause them to
thicken.
Cells in our liver
produce almost 90%
of the circulating
cholesterol.
78

79. Steroid
Hormones
Estrogen
Testosterone
79

80. Phospholipids
& Waxes
Phospholipids
are the major
component of
the cell
membrane.
Waxes are
strongly
hydrophobic.
80

81. 81

82. Take-Home Message 2.13
Cholesterol and
phospholipids are lipids
that are not fats.
Both are important
components in cell
membranes.
Cholesterol also serves
as a precursor to steroid
hormones, important
regulators of growth
and development.
82

83. 2.14–2.18
Proteins are
versatile
macromolecules
that serve as
building blocks.
83

84. 2.14 Proteins
are versatile
macromolecules
that serve as
building blocks.
84

85. Keratin:
structural
protein
85

86. Amino
Acids
20 different
amino acids
Strung
together to
make
proteins
86

87. 87

88. Nonpolar Amino Acids
Glycine
(Gly or G)
Alanine
(Ala or A)
Valine
(Val or V)
Leucine
(Leu or L)
Isoleucine
(Ile or I)
Methionine
(Met or M)
Phenylalanine
(Phe or F)
Tryptophan
(Trp or W)
Proline
(Pro or P)
88

89. Take-Home Message 2.14
Unique combinations of 20
amino acids give rise to
proteins, the chief building
blocks of physical structures
that make up all organisms.
Proteins perform myriad
functions, from assisting
chemical reactions to causing
blood clotting to building
bones to fighting
microorganisms.
89

90. 2.15 Proteins are an
essential dietary
component.
Growth
Repair
Replacement
90

91. Complete Proteins
Have all
essential amino
acids
Incomplete
proteins
Complementary
proteins
91

92. Insert new fig 2-38
92

93. Take-Home Message 2.15
Twenty amino acids make
up all the proteins
necessary for growth,
repair, and replacement of
tissue in living organisms.
Of these amino acids, about
half are essential for
humans: they cannot be
synthesized by the body so
must be consumed in the
diet.
Complete proteins contain
all essential amino acids,
while incomplete proteins
do not.
93

94. 2.16 Protein functions are influenced by their
three-dimensional shape.
94

95. 95

96. 96

97. 97Silk =  pleated sheet

98. 98
too freakin’ cute…
…it has eyelashes for
crying out loud! 

99. 99

100. 100

101. 101

102. Why do some people have curly hair and others
have straight hair?
102

103. Take-Home Message 2.16
The particular amino
acid sequence of a
protein determines
how it folds into a
particular shape.
This shape determines
many of the protein's
features, such as which
molecules it will
interact with.
When a protein's shape
is deformed, the
protein usually loses its
ability to function.
103

104. 2.17 Enzymes
are proteins
that initiate
and speed up
chemical
reactions.
104

105. Substrates
Active
Site
Enzyme
105
Enzymatic proteins =
Catalysts

106. 106

107. 107

108. Activation Energy
 Chemical reactions occurring in organisms
can either release energy or consume
energy.
 In either case, the reaction needs a little
“push” in order to initiate the
reaction―called activation energy.
 Enzymes act as catalyst by lowering the
activation energy.
108

109. Take-Home Message 2.17
Enzymes are proteins
that help initiate and
speed up chemical
reactions.
They aren't
permanently altered in
the process but rather
can be used again and
again.
109

110. 2-18 Enzymes regulate reactions in
several ways
(but malformed enzymes can cause
problems).
110

111. 111

112. 112

113. 113

114. 114

115. “Misspelled”
Proteins
Incorrect amino
acid sequence
Active site
disruptions
Phenylketonuria
115

116. 116

117. 117

118. Take-Home Message 2.18
Enzyme activity is influenced by
physical factors such as
temperature and pH, as well as
chemical factors, including
enzyme and substrate
concentrations.
Inhibitors and activators are
chemicals that bind to enzymes,
and by blocking the active site or
altering the shape or structure of
the enzyme can change the rate
at which the enzyme catalyzes
reactions.
118

119. 2.19–2.21
Nucleic acids
store information
on how to build
and run a body.
119

120. 2.19 Nucleic
acids are
macromolecules
that store
information.
120

121. Two Types of
Nucleic Acids
Ribonucleic acid
(RNA)
Deoxyribonucleic
acid (DNA)
Both play central
roles in directing
the production of
proteins.
121

122. 122

123. Information
Storage
The information in a
molecule of DNA is
determined by its
sequence of bases.
Adenine, Guanine,
Cytosine, &
Thymine
CGATTACCCGAT
123

124. Take-Home Message 2.19
The nucleic acids DNA and
RNA are macromolecules
that store information by
having unique sequences
of molecules.
Both play central roles in
directing protein
production in organisms.
124

125. 2.20 DNA
holds the
genetic
information
to build an
organism.
125

126. Base-Pairing
A & T
C & G
What is the
complimentary
strand to this strand:
CCCCTTAGGAACC?
126

127. Take-Home Message 2.20
DNA is like a ladder in which the
long vertical element of the
ladder is made from a sequence
of sugar-phosphate-sugar-
phosphate molecules and rungs
are nucleotide bases.
The sequence of nucleotide
bases contains the information
about how to produce a
particular protein.
127

128. 2.21 RNA is a universal translator, reading DNA
and directing protein production.
128

129. 129

130. RNA differs from
DNA in three
important ways.
The sugar
molecule of the
sugar-phosphate
backbone
Single-stranded
Uracil (U) replaces
thymine (T)
130

131. Take-Home Message 2.21
RNA acts as a middleman
molecule—taking the instructions
for protein production from DNA
to another part of the cell where,
in accordance with the RNA
instructions, amino acids are
pieced together into proteins.
131