Biology 1 1
Chapter 2 The Chemistry of Life
Summary ....................................................................................................................................................... 2
Vocabulary Review ........................................................................................................................................ 4
Protons, Neutrons, and Electrons ................................................................................................................. 5
Isotopes ......................................................................................................................................................... 6
Section Assessment 2-1 The Nature of Matter ............................................................................................. 9
Workbook Section 2–1 The Nature of Matter (pages 35–39) .................................................................... 10
Section Review 2-1 ...................................................................................................................................... 12
Section Assessment 2-2 Properties of Water ............................................................................................. 13
Workbook Section 2–2 Properties of Water (pages 40–43) ...................................................................... 14
Section Review 2-2 ...................................................................................................................................... 17
Enrichment 2-2 Special Solutions: Suspensions and Colloids ..................................................................... 18
A LITTLE CHEMISTRY REVIEW...................................................................................................................... 19
Section Assessment 2-3 Carbon Compounds ............................................................................................. 23
Workbook Section 2–3 Carbon Compounds (pages 44–48) ....................................................................... 24
More Review Questions 2-3........................................................................................................................ 28
Concept Map Chapter 2 .............................................................................................................................. 34
Chapter 1 Assessment................................................................................................................................. 35
SUBUNITS/MOLECULES............................................................................................................................... 38
MOLECULES................................................................................................................................................. 39
Biology 1 2
Chapter 2 The Chemistry of Life
Summary
2–1 The Nature of Matter
2–2 Properties of Water
The basic unit of matter is the atom. The
subatomic particles that make up atoms are
protons, neutrons, and electrons. Protons
and neutrons have about the same mass.
Protons are positively charged particles (+),
and neutrons carry no charge. Protons and
neutrons together form the nucleus, at the
center of the atom. The electron is a
negatively charged particle (_). Atoms have
equal numbers of electrons and protons,
and therefore atoms do not have a charge.
A chemical element is a pure substance
that consists entirely of one type of atom.
The number of protons in an atom of an
element is the element’s atomic number.
Atoms of an element can have different
numbers of neutrons. Atoms of the same
element that differ in the number of
neutrons they contain are known as
isotopes. Because all the isotopes of an
element have the same number of
electrons, they all have the same chemical
properties. A chemical compound is a
substance formed by the chemical
combination of two or more elements in
definite proportions. Atoms in compounds
are held together by chemical bonds. An
ionic bond is formed when one or more
electrons are transferred from one atom to
another. A covalent bond forms when
electrons are shared between atoms. The
structure that results when atoms are joined
together by covalent bonds is called a
molecule. Unequal sharing of electrons
creates regions of positive and negative
charges in molecules. Slight attraction can
develop between the oppositely charged
regions of nearby molecules. Such
intermolecular forces of attraction are called
van der Waals forces.
The water molecule (H2O) is neutral. Yet,
the oxygen end of the molecule has a slight
positive charge, and the hydrogen end has
a slight negative charge. A molecule in
which the charges are unevenly distributed
is called a polar molecule. Polar molecules
can attract each other. The attraction
between the hydrogen atom on one water
molecule and the oxygen atom on another
water molecule is called a hydrogen bond.
Cohesion is an attraction between
molecules of the same substance.
Adhesion is an attraction between
molecules of different substances. A
mixture is a material composed of two or
more elements or compounds that are
physically mixed together—the substances
are not chemically combined. A solution is a
mixture in which all the components are
evenly distributed throughout the mixture. In
a solution, the substance that is dissolved is
called the solute. The substance in which
the solute dissolves is called the solvent.
Water is the greatest solvent on Earth. A
water molecule can react to form ions. A
water molecule (H2O) can form a hydrogen
ion (H+) and a hydroxide ion (OH_). The pH
scale indicates the concentration of H+ ions
in a solution. Pure water has a pH of 7. An
acid is any compound that forms H+ ions in
solution. Acidic solutions contain higher
concentrations of H+ ions than pure water. A
base is a compound that produces OH_ ions
in solution. Basic, or alkaline, solutions
contain lower concentrations of H+ ions than
pure water and have pH values above 7.
2–3 Carbon Compounds
Organic chemistry is the study of all
compounds that contain bonds between
carbon atoms. Carbon compounds are also
called organic compounds. Many of the
molecules in living things are so large that
Biology 1 3
Chapter 2 The Chemistry of Life
they are known as macromolecules.
Macromolecules are formed in a process
called polymerization. Smaller units, called
monomers, join together to form
macromolecules, or polymers. Four groups
of organic compounds found in living things
are carbohydrates, lipids, nucleic acids, and
proteins. Carbohydrates are compounds
made up of carbon, hydrogen, and oxygen
atoms. Living things use carbohydrates as
their main source of energy. Plants and
some animals use carbohydrates in
structures. Starches and sugars are
examples of carbohydrates. Lipids are
made mostly from carbon and hydrogen
atoms. Fats, oils, and waxes are lipids.
Lipids are used in living things to store
energy. Some lipids are important parts of
biological membranes and waterproof
coverings. Lipid molecules are made up of
compounds called fatty acids and glycerol.
Nucleic acids contain hydrogen, oxygen,
nitrogen, carbon, and phosphorus.
Nucleotides are the monomers that make
up nucleic acids. Each nucleotide consists
of a 5-carbon sugar, a phosphate group,
and a nitrogenous base. Nucleic acids store
and transmit hereditary, or genetic,
information. There are two kinds of nucleic
acids: ribonucleic acid (RNA) and
deoxyribonucleic acid (DNA). Proteins
contain nitrogen as well as carbon,
hydrogen, and oxygen. Proteins are
polymers of molecules called amino acids.
Some proteins control the rate of reactions
and regulate cell processes. Some are used
to form bones and muscles. Others
transport substances into or out of cells or
help to fight disease.
Biology 1 4
Chapter 2 The Chemistry of Life
Vocabulary Review
Crossword Puzzle Use the clues below to fill in the spaces in the puzzle with the correct
words.
Across
17. macromolecule formed when monomers
1. elements or compounds that enter into
join together
Down
a chemical reaction
4. process that changes one set of
2. negatively charge subatomic particle
3. compound that produces hydroxide
chemicals into another
7. positively charged subatomic particle
ions in solution
8. substance formed by the chemical
5. bond formed when one or more electrons
combination of two or more elements in
are transferred from one atom to another
6. monomer of nucleic acid
definite proportions
11. positively and negatively charged
9. monomer of protein
10. compound that forms hydrogen ions in
atoms
12. carbon compound that stores and
solution
13. atom of same element that differs in
transmits genetic information
14. the center of an atom
number of neutrons compared to other
16. bond formed when electrons are shared
atoms of the element
15. basic unit of matter
between atoms
Biology 1 5
Chapter 2 The Chemistry of Life
2-1 The nature of matter
Protons, Neutrons, and Electrons
The diagram shows a model of an atom. It shows the nucleus, protons, neutrons, and
electrons. The diagram is not to scale. Label a proton, a neutron, an electron, and the
nucleus. Then, color the protons green, the neutrons purple, and the electrons orange.
Use the diagram to answer the questions.
1. What are the negatively charged electrons attracted to?
___________________________________________________________________________
___________________________________________________________
2. Which of the following describes the charge of a neutron?
Circle the correct answer.
Positive
negative
no charge
Biology 1 6
Chapter 2 The Chemistry of Life
Isotopes
Isotopes are atoms of an element that have the same number of protons but a different
number of neutrons. The number of protons plus the number of neutrons in an isotope is
called its mass number. Carbon-12, for example, has 6 protons and 6 neutrons so its mass
number is 12.
Draw the correct number of protons and neutrons for each isotope. Indicate protons with a
plus sign (_). Write the number of protons and neutrons in each isotope.
Use the diagram to answer the questions.
1. Name one difference between carbon-12 and carbon-14.
___________________________________________________________________
___________________________________________________________________
______________________________________________
2. Name one way in which carbon-12 and carbon-14 are alike.
___________________________________________________________________
___________________________________________________________________
__________________________________________________________________
Biology 1 7
Chapter 2 The Chemistry of Life
Ionic Bonds
In an ionic bond, one atom transfers one or more electrons to another atom. The atom that
loses the electron(s) becomes a positively charged ion. The atom that gains the electron(s)
becomes a negatively charged ion.
Count the electrons in each atom or ion. Write this number in the space provided. Then
determine the charge of the atom or ion.
Use the diagram to answer the questions. Circle the correct answer.
1. Which of these is negatively charged?
sodium atom
chloride ion
2. Which of these is positively charged?
sodium ion
chlorine atom
3. The diagram above shows the formation of sodium chloride.
What kind of substance is sodium chloride?
a compound
an element
Biology 1 8
Chapter 2 The Chemistry of Life
Covalent Bonds
In a covalent bond, two atoms share electrons. The electrons move in the orbitals of both atoms. In
a single covalent bond, they share two electrons. One oxygen atom can form single covalent
bonds with two hydrogen atoms to make water.
Color the electrons in the oxygen atom orange. Use purple to fill in the electrons in both hydrogen
atoms.
Use the illustrations to answer the question.
1. What is the name of the structure formed when atoms are joined by covalent bonds?
__________________________________________________________________________________________
__________________________________________________________________________________________
Biology 1 9
Chapter 2 The Chemistry of Life
Section Assessment 2-1 The Nature of Matter
1Describe the structure of an atom.
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
2Why do all isotopes of an element have the same chemical properties? In what way do isotopes
of an element differ?
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
________________________________________________________________________________
3What is a covalent bond? An ionic Bond?
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
4What is a compound? How are compounds related to molecules?
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
Biology 1 10
Chapter 2 The Chemistry of Life
Workbook Section 2–1 The Nature of Matter (pages 35–39)
This section identifies the three particles that make up atoms. It also explains how atoms of the same element can have
a different number of neutrons and describes the two main types of chemical bonds.
Atoms (page 35)
1. The basic unit of matter is called a(an) ____________________ .
2. Describe the nucleus of an atom. _________________________________________________________________
______________________________________________________________________________________________
3. Complete the table about subatomic particles.
SUBATOMIC PARTICLES
4. Why are atoms neutral despite having charged particles? _______________________________________________
_______________________________________________________________________________________________
Elements and Isotopes (page 36)
5. What is a chemical element? ______________________________________________________________________
_______________________________________________________________________________________________
6. What does an element’s atomic number represent? ____________________________________________________
_______________________________________________________________________________________________
7. Atoms of the same element that differ in the number of neutrons they contain are known as
_________________________.
8. How are isotopes identified? ____________________________________________.
9. Why do all isotopes of an element have the same chemical properties? ____________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
Chemical Compounds (page 37)
10. What is a chemical compound? __________________________________________________________________
_______________________________________________________________________________________________
11. What does the formula for table salt indicate about that compound? ______________________________________
_______________________________________________________________________________________________
Biology 1 11
Chapter 2 The Chemistry of Life
Chemical Bonds (pages 38–39)
12. What holds atoms in compounds together? _________________________________________________________
_______________________________________________________________________________________________
13. Complete the table about the main types of chemical bonds. ____________________________________________
_______________________________________________________________________________________________
14. What is an ion? _______________________________________________________________________________
_______________________________________________________________________________________________
15. Is the following sentence true or false? An atom that loses electrons has a negative charge. _________________
16. The structure that results when atoms are joined together by covalent bonds is called a(an) ________________.
17. Circle the letter of each sentence that is true about covalent bonds.
a. When atoms share two electrons, it is called a double bond.
b. In a water molecule, each hydrogen atom forms a single covalent bond.
c. Atoms can share six electrons and form a triple bond.
d. In a covalent bond, atoms share electrons.
18. The slight attractions that develop between oppositely charged regions of nearby molecules are called
______________________________ .
Biology 1 12
Chapter 2 The Chemistry of Life
Section Review 2-1
Completion On the lines provided, complete the following sentences.
1. The nucleus, the center of the atom, is made up of _________________ and ____________________.
2. The negatively charged particles in atoms are called ____________________.
3. Different isotopes of the same element have different numbers of ____________________.
4. Isotopes of the same element have the same chemical properties because they have the same number of
____________________.
5. In a(an) ____________________ bond, electrons are transferred from one atom to another.
Short Answer On the lines provided, answer the following questions.
6. Describe the two main types of chemical bonds that are found in compounds.
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
7. Explain how an atom becomes an ion.
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
Reviewing Key Skills
8. Comparing and Contrasting. What are the similarities and differences between electrons and protons?
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
9. Applying Concepts What is the relationship between atoms and molecules?
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
10. Inferring What property of radioactive isotopes allows them to be used to determine the age of rocks and fossils?
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
Biology 1 13
Chapter 2 The Chemistry of Life
Section Assessment 2-2 Properties of Water
1Use the structure of a water molecule to explain why it is polar.
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
2Compare acidic and basic solutions in terms of their H+ ions and OH- ion concentrations
__________________________________________________________________________________
__________________________________________________________________________________
_________________________________________________________________________________
3What is the difference between a solution and a suspension?
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
4What does pH measure?
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
5The strong acid hydrogen fluoride (HF) can be dissolved in pure water. Will the pH of the
solution be greater of less than 7?
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
Draw a concept map on the properties of water. Include the following terms in your concept map:
hydrogen bonds, polarity, cohesion, adhesion, capillary action, and solvent.
Biology 1 14
Chapter 2 The Chemistry of Life
Workbook Section 2–2 Properties of Water (pages 40–43)
This section describes the makeup of water molecules. It also explains what acidic solutions and basic solutions
are.
The Water Molecule (pages 40–41)
1. Is the following sentence true or false? A water molecule is neutral. _________________
2. What results from the oxygen atom being at one end of a water molecule and the hydrogen atoms being at
the other end?
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
3. Why is a water molecule polar?________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
4. Circle the letter of each sentence that is true about hydrogen bonds.
a. A hydrogen bond is stronger than an ionic bond.
b. The attraction between the hydrogen atom on one water molecule and the oxygen atom on another
water molecule is an example.
c. A hydrogen bond is stronger than a covalent bond.
d. They are the strongest bonds that form between molecules.
5. Complete the table about forms of attraction.
6. Why is water extremely cohesive? ______________________________________________________
_____________________________________________________________________________________
7. The rise of water in a narrow tube against the force of gravity is called _________________________ .
8. How does capillary action affect plants? _____________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
Biology 1 15
Chapter 2 The Chemistry of Life
Solutions and Suspensions (pages 41–42)
9. What is a mixture? ___________________________________________________________________________________
_________________________________________________________________________________________________________
10. A mixture of two or more substances in which the molecules of the substances are
evenly mixed is called a(an) _______________________.
11. The greatest solvent in the world is _______________________.
12. What is a suspension? ________________________________________________________________________________
_________________________________________________________________________________________________________
13. Complete the table about substances in solutions.
Acids, Bases, and pH (pages 42–43)
14. Two water molecules can react to form __________________________.
15. Why is water neutral despite the production of hydrogen ions and hydroxide ions?
_______________________________________________________________________________________________
_______________________________________________________________________________________________
16. What does the pH scale indicate? ________________________________________________________
_____________________________________________________________________________________
17. On the pH scale below, indicate which direction is increasingly acidic and which is
increasingly basic.
18. How many more H+ ions does a solution with a pH of 4 have than a solution with a
pH of 5? ____________________________
Biology 1 16
Chapter 2 The Chemistry of Life
19. Circle the letter of each sentence that is true about acids.
a. Acidic solutions have pH values below 7.
b. An acid is any compound that forms H+ ions in solution.
c. Strong acids have pH values ranging from 11 to 14.
d. Acidic solutions contain higher concentrations of H+ ions than pure water.
20. Circle the letter of each sentence that is true about bases.
a. Alkaline solutions have pH values below 7.
b. A base is a compound that produces OH– ions in solution.
c. Strong bases have pH values ranging from 11 to 14.
d. Basic solutions contain lower concentrations of H+ ions than pure water.
21. What are buffers?
__________________________________________________________________________________
__________________________________________________________________________________
_______________________________________________________
Biology 1 17
Chapter 2 The Chemistry of Life
Section Review 2-2
Reviewing Key Concepts
Matching Match each term with its appropriate description. Write the letter of the correct term on the lines
provided. A term may be used more than once.
a. polarity
b. acidic
c. basic
_____________ 1. unequal sharing of electrons
_____________ 2. lemon juice, pH 1.5
_____________ 3. lower concentrations of H_ ions than pure water
_____________ 4. ammonia, pH 11.5
_____________ 5. a slight negative charge at one end of a molecule, a slight positive charge at the other
end
_____________ 6. pH values that are below 7
_____________ 7. alkaline solutions
Short Answer On the lines provided, answer the following questions.
8. What causes polarity in a water molecule?
_____________________________________________________________________________________
___________________________________________________________________
9. What determines whether a solution is acidic or basic?
_____________________________________________________________________________________
___________________________________________________________________
10. What is the relationship between cohesion and capillary action?
_____________________________________________________________________________________
___________________________________________________________________
11. Name two types of mixtures and describe how they are different.
_____________________________________________________________________________________
___________________________________________________________________
Reviewing Key Skills
12. Applying Concepts What is the relationship between a base and a basic solution?
_____________________________________________________________________________________
___________________________________________________________________
13. Comparing and Contrasting Describe how acidic solutions differ from pure water.
_____________________________________________________________________________________
___________________________________________________________________
14. Applying Concepts What are buffers and why are they important to cells?
_____________________________________________________________________________________
___________________________________________________________________
Biology 1 18
Chapter 2 The Chemistry of Life
Enrichment 2-2 Special Solutions: Suspensions and Colloids
Colloids and suspensions may look like solutions, but they are actually significantly different from
solutions. As you know, particles in a solution do not settle; they are in constant motion. The particles in a
solution are also small enough to pass through the fine pores of a membrane.
A suspension is a liquid or gas containing an evenly dispersed solid. Due to gravity, the solid
particles eventually settle out of the liquid or gas. For example, if you shake a piece of clay in water, the clay
particles become suspended. When you stop shaking the suspension, the particles of clay begin to settle.
The particles in a typical suspension are much larger than the particles in solution. The particles in a colloid
are smaller than suspension particles and larger than solution particles. Colloid particles do not settle as
suspension particles do. Colloid particles cannot pass through the pores of a membrane, and they diffuse
very slowly.
There are several different types of colloids. Colloids may be classified according to the materials of
which they are made. For example, many salad dressings, when shaken, are temporary colloids, made by
combining two liquids. If the dressing includes egg yolk, the mixture emulsifies and becomes a stable colloid
called an emulsion. An emulsion is a dispersion of nonsoluble drops of one liquid into another liquid. Smoke
is another kind of colloid, formed by solids dispersed in a gas.
Evaluation On the lines provided, answer the following questions.
1. Examine the table of types of colloids. What kinds of colloids are found in living things? In nonliving
things?
_____________________________________________________________________________________
_____________________________________________________________________________________
__________________________________________________________
2. What are some similarities between colloids and suspensions? What are some differences?
__________________________________________________________________________________
__________________________________________________________________________________
_______________________________________________________
Biology 1 19
Chapter 2 The Chemistry of Life
A LITTLE CHEMISTRY REVIEW
Chapter 2-1 and 2-2
MULTIPLE CHOICE:
Circle the letter for ALL the answers that are TRUE. THERE MAY BE MORE THAN ONE CORRECT
ANSWER.
The attraction between the hydrogen atom in one water molecule and the oxygen molecule in another is an
example of a ____________________ bond.
A. polymer
B. acidic
C. hydrogen
D. ionic
Which of the following is/are TRUE about water?
A. It is a good solvent because it dissolves many kinds of molecules.
B. It helps in homeostasis because it doesn’t change temperature easily.
C. It is polar and forms hydrogen bonds that help water molecules stick together.
D. It makes up approximately 70% of all living things and is an important participant/product in
many chemical reactions.
ATOMS with an electric charge are called ________________
A. molecules
B. electrons
C. polar
D. ions
MOLECULES that have an uneven pattern of electric charge (more positive in one area; more negative in
another) are said to be _____________________
A. nucleic
B. polar
C. non-polar
D. ionic
A water molecule is made up of ___________________________.
A. two hydrogen atoms and one oxygen atom
B. one hydrogen atom and two oxygen atoms
C. one hydrogen atom and 3 carbon atoms
D. two hydrogen atoms and 1 sodium ion
Circle all of the molecules which are made by joining subunits using dehydration synthesis.
Biology 1 20
Chapter 2 The Chemistry of Life
A. proteins
B. nucleic acids
C. lipids
D. polysaccharides
LABEL THE FOLLOWING CHEMICAL REACTIONS:
______________________________________
___________________________________
MODIFIED TRUE or FALSE
Circle T if the statement is TRUE.
Circle F if the statement is FALSE and use the blank provided to correct the underlined word/phrase.
T
F The slight attractions that develop between oppositely charged regions of nearby molecules
are called van Leuwenhoek forces. __________________________
T
F Molecules that are really, really large are called micromolecules. ____________________
T
F Hydrophilic molecules are “water fearing” and try to stay away from water or other polar
molecules. ______________________
Biology 1 21
Chapter 2 The Chemistry of Life
T
F Reactants are written on the left hand side of the arrow in a chemical equation. __________
T
F Non-polar molecules are hydrophilic. _______________________
MATCH THE DESCRIPTION WITH THE
CORRECT LETTER FOR EACH PARTICLE
OR PARTICLES:
You can use them more than once!
E for ELECTRON
_______ positively charged
_______ orbits the nucleus in energy levels
_______ uncharged or neutral
P FOR PROTON
_______ negatively charged
N FOR NEUTRON
_______ & ______ found in the nucleus
FILL IN THE CHARTS BELOW FOR ATOMS/IONS IMPORTANT TO LIVING THINGS:
ATOM NAME
SYMBOL
CARBON
SYMBOL
CALCIUM ION
N
K+
O
Cl-
HYDROGEN
SODIUM ION
P
SULFUR
IONS
HYDROGEN
ION
Biology 1 22
Chapter 2 The Chemistry of Life
Types of Molecules 2-3
Living things need organic compounds called carbohydrates, lipids, nucleic acids,
and proteins.
Fill in the missing cells in the table. Identify the function of the molecule or the
main components (types of atoms) that make up the molecule. The first row has
been done for you.
Use the table to answer the question.
1. Which of the types of molecules in the table contain carbon?
_________________________________________________________________________
_________________________________________________________________________
Biology 1 23
Chapter 2 The Chemistry of Life
Section Assessment 2-3 Carbon Compounds
1Name four groups of organic compounds found in living things.
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
2Describe at least one function of each group of organic compounds.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
3What properties of carbon explain carbon’s ability to form many different
macromolecules?
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
4Explain why proteins are considered polymers but lipids are not.
_________________________________________________________________________
_________________________________________________________________________
5Compare the structures and functions of the biomolecules lipids and starches.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
Biology 1 24
Chapter 2 The Chemistry of Life
Workbook Section 2–3 Carbon Compounds (pages 44–48)
This section explains how the element carbon is able to form millions of carbon, or organic,
compounds. It also describes the four groups of organic compounds found in living things.
The Chemistry of Carbon (page 44)
1. How many valence electrons does each carbon atom have? ______________________
_____________________________________________________________________________________
2. What gives carbon the ability to form chains that are almost unlimited in length?
_________________________________________________________________________
_________________________________________________________________________
Macromolecules (page 45)
3. Many of the molecules in living cells are so large that they are known as
____________________..
.
4. What is the process called by which macromolecules are formed? ____________________.
5. When monomers join together, what do they form? _______________________
6. What are four groups of organic compounds found in living things?
a. ________________________
b. ________________________
c. ________________________
d. ________________________
Carbohydrates (pages 45–46)
7. What atoms make up carbohydrates? ________________________________________
8. Circle the letter of each sentence that is true about carbohydrates.
a. Starches and sugars are examples of carbohydrates.
b. Living things use them as their main source of energy.
c. The monomers in sugar polymers are starch molecules.
d. Plants and some animals use them for strength and rigidity.
9. Single sugar molecules are also called ______________________.
10. Circle the letter of each monosaccharide.
a. galactose
b. glycogen
c. glucose
d. fructose
11. What are polysaccharides? _______________________________________________
12. How do plants and animals store excess sugar?_______________________________
_________________________________________________________________________
Biology 1 25
Chapter 2 The Chemistry of Life
Lipids (pages 46–47)
13. What kinds of atoms are lipids mostly made of? _____________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
14. What are three common categories of lipids?
a.________________
b. ______________
c. _______________
15. Many lipids are formed when a glycerol molecule combines with compounds
called _________________________
16. Circle the letter of each way that fats are used in living things.
a. As parts of biological membranes
b. To store energy
c. To give plants rigidity
d. As chemical messengers
17. Complete the table about lipids.
Nucleic Acids (page 47)
18. Nucleic acids contain what kinds of atoms? _________________________________________
_____________________________________________________________________________________
19. The monomers that make up nucleic acids are known as ________________________.
20. A nucleotide consists of what three parts? __________________________________________
_____________________________________________________________________________________
Biology 1 26
Chapter 2 The Chemistry of Life
21. What is the function of nucleic acids in living things?____________________________
_________________________________________________________________________
_________________________________________________________________________
22. What are two kinds of nucleic acids?
a._____________________________________________________
b. _____________________________________________________
Proteins (pages 47–48)
23. Proteins contain what kinds of atoms? _______________________________________
_____________________________________________________________________________________
24. Proteins are polymers of molecules called ______________________________.
25. What are four roles that proteins play in living things?
a. ___________________________________________________________________________________
b. __________________________________________________________________________________
c. ___________________________________________________________________________________
d. __________________________________________________________________________________
Biology 1 27
Chapter 2 The Chemistry of Life
Section Review 2-3
Reviewing Key Concepts
Identifying On the lines provided, identify each statement as describing carbohydrates, lipids,
nucleic acids, or proteins.
______________ 1. the main source of energy for living things
______________ 2. help carry out chemical reactions
______________ 3. important parts of biological membranes
______________ 4. contain hydrogen, oxygen, nitrogen, phosphorus, and carbon
______________ 5. transport substances in and out of cells
______________ 6. composed of amino acids
______________ 7. sugar and starches
______________ 8. store and transmit hereditary information
Completion On the lines provided, complete the following sentences.
9. Lipids are made up of fatty acids and ________________________.
10. Glucose, galactose, and fructose are carbohydrates called _________________________ .
11. The two basic kinds of nucleic acids are and ______________.
12. ______________ are polymers of amino acids.
13. A fatty acid with the maximum number of hydrogen atoms possible is ______________.
Reviewing Key Skills
14. Applying Concepts No other element can form the amount and variety of molecules that
carbon can form. What characteristics does carbon have that explain this characteristic?
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
15. Comparing and Contrasting Plastics are synthetic, organic polymers. How are plastics
similar to polysaccharides? How are they different?
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
Biology 1 28
Chapter 2 The Chemistry of Life
More Review Questions 2-3
BIOMOLECULES
MULTIPLE CHOICE:
Circle the letter for ALL the answers that are TRUE. THERE MAY BE MORE THAN ONE
CORRECT ANSWER.
NO other kind of atom can form the number and variety of molecules that
___________________ can because it can bond to 4 other atoms at the same time to make
carbohydrates, lipids, nucleic acids, and proteins.
A. hydrogen
B. oxygen
C. carbon
D. sodium
A ____________________ is made up of a sugar, a nitrogen base, and a phosphate group.
A. amino acid
B. nucleotide
C. phospholipid
D. glycoprotein
Circle the nitrogen base found in DNA but NOT RNA is _____________________
Adenine
Thymine
Guanine
Cytosine
Uracil
Lipids are different from other macromolecules because they ___________________
A. are hydrophobic and don’t dissolve in water
B. contain carbon, hydrogen and oxygen in a ratio of 1:2:1
C. dissolve easily in water
D. form large protein molecules
E. are hydrophilic
Glycogen, cellulose, and starch are all __________________.
A. proteins
B. polysaccharides
C. nucleic acids
D. lipids
E. phospholipids
Which 2 kinds of molecules combine to form cell membranes?
A. nucleic acids and carbohydrates
B. phospholipids and proteins
C. carbohydrates and nucleic acids
D. polysaccharides and RNA
Biology 1 29
Chapter 2 The Chemistry of Life
Adenine, thymine, guanine, cytosine, and uracil are all _____________________
A. amino acids used to make proteins
B. carbohydrates used to make polysaccharides
C. lipids used to make phospholipids
D. nitrogen bases used to make nucleotides
Which part of a phospholipid molecule is NON-POLAR & HYDROPHOBIC?
A. the lipid “tails”
B. the glycerol/phosphate “head”
This molecule is a(n) ________________________
A. nucleic acid
B. amino acid
C. phospholipid
D. carbohydrate
This molecule is ___________________
A. insulin
B. hemoglobin
C. glucose
D. a phospholipid
E. ATP
*
*
*
*
*
*
*
*
*
*
*
*
*
MATCH THE MOLECULE WITH THE SUBUNIT THAT BUILDS IT:
________ POLYSACCHARIDES
________ NUCLEIC ACIDS
________ PROTEINS
A
*
*
*
*
*
*
*
B
*
*
*
C
*
*
*
Biology 1 30
Chapter 2 The Chemistry of Life
TRUE or FALSE
Circle T if the statement is TRUE
Circle F if the statement in FALSE and use the blank provided to correct the underlined
word/phrase.
T
F
The 20 different polysaccharides used to make proteins differ in what is attached
in their R group position.
_____________________
T
F
Cellulose is a structural polysaccharide that makes plants sturdy.
___________________
T
F
One function of proteins is to provide insulation. __________________
T
F
People with diabetes can’t make hemoglobin to control their blood sugar.
__________________________
Match the molecule with its description:
LIPIDS
CARBOHYDRATES
PROTEINS NUCLEIC ACIDS
____________________________ made by joining amino acid subunits in long chains which
provide a wide variety of functions in cells
____________________________ made from carbon, hydrogen, and oxygen atoms in a 1:2:1
ratio
____________________________ made from nucleotide subunits which store and carry
information
____________________________ Hydrophobic fats, oils, waxes, & steroids made mainly from
carbon and hydrogen atoms in long chains or multiple rings
COMPARE:
KINDS OF
CARBOHYDRATES
MONOSACCHARIDES
POLYSACCHARIDES
# of SUGARS it
contains
GIVE 3 EXAMPLES
Biology 1 31
Chapter 2 The Chemistry of Life
MACROMOLECULES
GIVE SOME FUNCTIONS OF EACH
1.
CARBOHYDRATES
2.
1.
NUCLEIC ACIDS
2.
1.
LIPIDS
2.
1.
PROTEINS
2.
Believe it or not there are
even more than these!
3.
4.
5.
Biology 1 32
Chapter 2 The Chemistry of Life
COMPARE NUCLEIC ACIDS:
DNA
RNA
Is it Single/double stranded?
Which Nitrogen bases does it
contain?
Which Sugar does it contain?
Function(s)?
NAME THE MOLELCULE
DESCRIBED BELOW
Protein hormone that tells animal cells to store blood glucose
as glycogen
Double stranded nucleic acid made from nucleotides subunits
containing A, T, G, and C that stores genetic info in cells
Protein found in red blood cells that carries oxygen to the body
Membrane protein with carbohydrates attached that helps cells
identify “self” and plays a role in blood types, organ
Biology 1 33
Chapter 2 The Chemistry of Life
transplants, and germ recognition
Macromolecule with a polar glycerol/phosphate “head” and 2
non-polar hydrophobic “tails” used to make cell membranes
Single stranded nucleic acid made from nucleotide subunits
containing A, U, C, and G which carries information from the
DNA to the cell for protein synthesis
Storage form of glucose used by plant cells
Storage form of glucose used by animal cells
Structural polysaccharide made from glucose subunits that
makes plants sturdy
Nucleotide subunit made from ribose sugar, adenine, and 3
phosphates which stores and transports ENERGY in cells
Polar molecule made from 1 oxygen and 2 hydrogen atoms
that is required by all living things
Biology 1 34
Chapter 2 The Chemistry of Life
Concept Map Chapter 2
Using the information from the chapter, complete the concept map below. If there is not enough
room in the concept map to write your answers, write them on a separate sheet of paper.
Biology 1 35
Chapter 2 The Chemistry of Life
Chapter 1 Assessment
1abcd-
The positively charged particle in an atom is the
Neutron
Ion
Proton
electron
abcd-
Two or more different atoms are combined in definite proportions in any
Symbol
Isotope
Element
Compound
abcd-
A covalent bond is formed by the
Transfer of electrons
Sharing electrons
Gaining of electrons
Losing of electrons
abcd-
When you shake sugar and sand together in a test tube, you cause them to form a
Compound
Mixture
Solution
Suspension.
abcd-
A compound that produces hydrogen ions in solutions is a(an)
Salt.
Acid.
Base.
polymer
abcd-
In polymerization, complex molecules are formed by the joining together of
Macromolecules
Carbohydrates
Polymers
monomers
2-
3-
4-
5-
6-
Biology 1 36
Chapter 2 The Chemistry of Life
7-
Which formula represents an amino acid?
8abcd-
Proteins are polymers formed from
Lipids
Carbohydrates
Amino acids
Nucleic acids.
9Explain the relationship among atoms, elements, are compounds.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
10What is a radioactive isotope?
_________________________________________________________________________
_________________________________________________________________________
Describe two scientific uses of radioactive isotopes.________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
11How are atoms in a compound held together?
_________________________________________________________________________
_________________________________________________________________________
Biology 1 37
Chapter 2 The Chemistry of Life
12Distinguish among single, double, and triple covalent bonds.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
13Explain the properties of cohesion and adhesion. Give an example of each property.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
14What is the relationship among solutions, solutes, and solvents?
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
15How are acids and bases different? ______________________________________
_________________________________________________________________________
_________________________________________________________________________
How do their pH values differ?_________________________________________________
_________________________________________________________________________
_________________________________________________________________________
16Explain the relationship between monomers and polymers, using polysaccharides as
an example._______________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
17Identify three major roles of proteins.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
18Describe the parts of a nucleotide.
_________________________________________________________________________
_________________________________________________________________________
19Name the two basic kinds of nucleic acids. What sugar does each contain?
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
20Suppose you wanted to increase the pH solution. What could you add to the solution
to increase the pH? Explain your prediction.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
Biology 1 38
Chapter 2 The Chemistry of Life
SUBUNITS/MOLECULES
ORGANIC MOLECULE
SUBUNIT
NUCLEOTIDE SUBUNITS
(A, T, G, C, or U)
MAKES THIS MACROMOLECULE
NUCLEIC ACIDS
(DNA OR RNA)
AMINO ACIDS
(20 different R groups)
PROTEINS
CARBOHYDRATES
SIMPLE SUGARS
MONOSACCHARIDES = 1 sugar
(Ex : glucose, fructose,
galactose, ribose, deoxyribose )
COMPLEX CARBO’s
1 carbon: 2 hydrogen: 1
oxygen
POLYSACCHARIDES=many sugars
(Ex : glycogen, starch, cellulose)
Mostly CARBON &
HYDROGEN ATOMS in long
chains or rings with
very little oxygen
LIPIDS
Includes: Fats, oils, waxes,
steroids
Biology 1 39
Chapter 2 The Chemistry of Life
MOLECULES
ADENOSINE
TRIPHOSPHATE
(ATP)
Stores energy
for cell activities
PHOSPHOLIPIDS
(polar head &
2 non-polar lipid tails)
Make cell
membranes
GLYCOPROTEINS
Cell identity;
Recognition
of “SELF”
(Protein with sugars
attached)
Biology 1 40
Chapter 2 The Chemistry of Life
Name: ________________________________________ Group: ______________________
You must have this page with you every class in order to get participation from your work. Do not lose it or you must cry at the
end of the semester.
Vocabulary Review
Protons, Neutrons and
Electrons
Isotopes
Ionic and Covalent Bond
Section Assessment 2-1
Workbook 2-1
Section Review 2-
Section Assessment 2-2
Workbook 2-2
Section Review 2-2
A little Chemistry Review
Section Assessment 2-3
Workbook 2-3
Section Review 2-3
Types of molecules 2-3
More Review Questions 2-3
\
Concept Map
Chapter Assessment 1
Biology 1 41
Chapter 2 The Chemistry of Life