Chapter 2: Introductory Chemistry—KEY 50 points
Focus on Wellness…DID YOU KNOW? (Pages 25 and 43)
1. Your Aunt Mary tells you she is taking an herbal weight-loss supplement. “It’s natural, so it’s
safe,” she says. In fact, it’s not working as well as it was two weeks ago, so she is now taking
double the recommended dose. What do you say to her? 1 point
_Natural does not necessary mean safe; natural chemicals are still chemicals. Something that is
effective cannot be simultaneously harmless; anything can have harmful physiological effects at
some dose. All drugs are toxic if you take too much!!! Note: herbal supplements are not
regulated and their makers can say whatever they want.________________________________
I. Introduction To Chemistry ¼ each = 2 ½ points
1. Define chemistry: _science of the structure and interactions of matter_____________________
2. Define matter: _anything that occupies space and has mass______________________________
3. Define mass: _amount of matter in any living thing_____________________________________
A. Chemical Elements and Atoms
4. _Chemical elements_ are substances that cannot be broken down into a simpler form by
ordinary chemical means.
5. How many elements are recognized by scientists according to your textbook? _112_____
6. How many different elements are found in the human body? _26_____
7. Which four elements make up about 96% of the human body (list their name and
chemical symbol)?
_carbon_______________ __C__
_hydrogen_______________ __H__
_oxygen_______________ __O__
_nitrogen________________ __N__
8. Which elements make up about 3.8% of the human body (list their name and chemical
symbol)?
_calcium______________ _Ca_
_sodium____________ _Na_
_phosphorus___________ _P_
_chlorine___________ _Cl_
_potassium ____________ _K_
_magnesium_________ _Mg_
_sulfur ________________ _S_
_iron_______________ _Fe_
9. Which elements make up about 0.2% of the human body (list their name and chemical
symbol)?
_aluminum____________ _Al_
_manganese___________ _Mn_
_boron_______________ _B_
_molybdenum__________ _Mo_
_chromium____________ _Cr_
_selenium_____________ _Se_
_cobalt_______________ _Co_
_silicon_______________ _Si_
_copper_______________ _Cu_
_tin__________________ _Sn_
_fluorine______________ _F_
_vanadium____________ _V_
_iodine________________ _I_
_zinc_________________ _Zn_
10. What are the 14 elements listed in number 7 above called? _trace elements________
B. Ions, Molecules, and Compounds
11. Distinguish between an ion, a molecule, and a compound. ¼ point
_ion: charged ion, gained or lost e-__________________________________________
_molecule: 2 or more atoms share electrons__________________________________
_compound: a molecule containing 2 or more different elements_________________
12. Look at the molecular chemical formula given below: Identify the elements in it by
underlining them, next identify the subscript by circling it, and finally identify the
coefficient by drawing a rectangular shape around it. ¼ point
2H2 O
2
13. What is a free radical? ¼ point —
_ion or molecule with an unpairedK electron in its outermost shell; highly unstable;
destructive to other nearby _
E
Example: _superoxide________________________________
Y
;
CHECKPOINT: 2 each = 4 points
1. Compare the meanings of atomic number, mass number, ion, and molecule.
_atomic number = number of protons n nucleus; mass number = protons +
neutrons; ions are charged particle (atom) that has lost or gained an e-; molecule
are formed when two or more atoms share electrons________________________
2. What is the significance of the valence (outer) electron shell of an atom?
_Chemically stable atoms have 8 electrons in their outer shells, and unlikely to form
chemical bonds. Atoms without 8 electrons in their outer shell form chemical bonds
easily because they want eight (octet rule)__________________________________
C. Chemical Bonds ¼ each = 1 point
14. Define chemical bond: _forces that bind the atoms of molecules and compounds
together, resisting their separation___________________________________________
15. When is an atom chemically stable?
_an atom with eight electrons in its outer electron shell___________________________
16. Will chemically stable atoms form chemical bonds? _NO_______
17. What is the octet rule? _atoms that do not have eight electrons in their outer shell,
given the right conditions, two or more of them can bond in ways the produce
chemically stable arrangements of eight electrons in the outer shell of each atom_____
1. Ionic Bonds a-e ¼ point each = 1 ¼ points
a. Define ionic bond: _force of attraction between ions of opposite charges_________
b. What is a cation? _protons exceeds electrons= positively charged atom__________
c. What is an anion? _ electrons exceeds protons= negatively charged atom ________
d. In the human body, where are ionic bonds mainly found and for what purpose?
_In teeth and bones, where they give strength to the tissue____________________
e. What is an electrolyte?
_an ionic compound that breaks down into cations and anions when dissolved____
f. Below are diagrams of a Lithium atom with 1 electron in its outer shell and a
Fluorine atom with 7 electrons in its outer shell. Using Figure 2.4 on page 26 of your
textbook for help, in the space below depict with labels how an ionic bond would
form between the lithium atom and the fluorine atom. Identify valence electron(s),
cation, and anion. 1 point
Lithium atom
Fluorine atom
Electron
donated
Valence electrons: in
outer shell
Li = 1
F=7
Cation
Anion
2. Covalent Bonds a-e ¼ each = 1 ¼ points
2
a. How do covalent bonds form?
_Neither atom loses or gains electrons; atoms form a molecule by sharing one, two,
or three pairs of their outer shell electrons__________________________________
b. Do covalent bonds easily break apart in water? _NO__________
c. What type of bond is shown here
O=O? _Double covalent bond__________
d. Explain the differences between structural formulas and molecular formulas.
_Structural formulas show the covalent bonds by a straight line between chemical
symbols for two atoms; molecular formulas the number of atoms in each molecule
is noted by subscripts___________________________________________________
e. Describe the difference between nonpolar and polar covalent bonds.
_Nonpolar covalent: atoms share the electrons equally-one does not attract the
shared electrons more strongly than the other atom; always nonpolar between two
identical atoms._______________________________________________________
_Polar covalent: sharing of electrons between atoms is unequal- one atom attracts
the shared electrons more strongly than the other; partial charge indicated by
lowercase Greek delta ( δ) with a minus or plus sign__________________________
Figure 2.5; Page 31:What is the main difference between an ionic bond and a covalent bond? _In
ionic bonds atoms gain or lose electrons; in covalent bonds they share electrons__1 point__________
3. Hydrogen Bonds ¼ each = ½ point
a. Are hydrogen bonds nonpolar covalent bonds or polar covalent bonds? _Polar ____
b. Why are hydrogen bonds so weak and what is their function in molecules, like DNA?
_formed from attraction of oppositely charged parts of molecules rather than
sharing electrons; cannot bind atoms into molecules but do form links between
molecules of different parts of a large molecule like DNA______________________
D. Chemical Reactions ¼ each = ½ point
18. How do chemical reactions occur?
_They occur when new bonds form and/or old bonds break between atoms; process
involves the transfer of energy__________________________________________________
19. What things are able to happen in human bodies because of chemical reactions?
_Body structures are built and body functions are carried out______________________
1. Forms of Energy and Chemical Reactions ¼ each = ½ point
a. List the two main forms of energy. _potential_ and _kinetic_
b. What is chemical energy and where is it stored?
_It is a form of potential energy that is stored in the bonds of molecules__________
2. Synthesis Reactions
These topics will be completed independently on the
3. Decomposition Reactions
‘Chemical Reactions and Compounds’ worksheet, under
4. Exchange Reactions
‘Chemical Reactions’, which will be due on the same day
5. Reversible Reactions
as your packet…
CHECKPOINT: 2 each = 4 points
1. Distinguish among ionic, covalent, and hydrogen bonds. _ionic bond: attraction between ions of
opposite charge; gain or lose e-. covalent bonds: no electrons lost or gained; atoms form
molecules by sharing one, two, or three pairs of their outer shell electrons. Hydrogen bonds:
Polar covalent bonds between hydrogen and other atoms is the third type of chemical bond;
hydrogen is slightly positively charged and attracts another atom with a slightly negative charge/
attraction between oppositely charged parts of molecules rather than sharing of electron. _____
2. Explain the difference between anabolism and catabolism. Which involves synthesis reactions?
Which involves decomposition reactions? _All synthesis reactions are collectively referred to as
anabolism; they built large molecules from small molecules; store energy. Decomposition
reactions are collectively referred to as catabolism; they break down large molecules into
smaller molecules; release energy________________________________________________
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II. Chemical Compounds and Life Processes ¼ point
1. Explain the main difference between inorganic and organic compounds and give examples of
each type.
_Inorganic compounds lack carbon, are structurally simple, held together by ionic or covalent
bonds; examples: water, many salts, acids, bases, and two-carbon containing compounds,
carbon dioxide (CO2 ) and bicarbonate ions (HCO3-)_____________________________________
_Organic compounds contain carbon, usually also contain hydrogen, always have covalent
bonds; examples: carbohydrates, lipids, proteins, nucleic acids, and adenosine triphosphate____
A. Inorganic Compounds ¼ each = 1 ¼ point
1. Water
a. List and briefly discuss five reasons why water is vital to human health.
1. _Excellent solvent: liquid or gas in which some other material (solute) has been
dissolved. Water carries nutrients, oxygen, and waste throughout the body___
2. _Participates in chemical reaction; decomposition (hydrolysis: loosens or breaks
apart; enables nutrients to be absorbed into the body) and synthesis_________
3. _Absorbs and releases heat very slowly; moderates the effects of changes in
environmental temperature; maintaining homeostasis_____________________
4. _Needs a large amount of heat to change from a liquid to a gas; thus when
sweat evaporates off the human body it takes large quantities of heat with it;
excellent cooling mechanism__________________________________________
5. _Serves as a lubricant; major part of saliva, mucus, and other lubricating fluids;
enables organs to slide over one another and is needed in joints where bones ,
ligaments, and tendons rub against one another__________________________
2. Inorganic Acids, Bases, and Salts ¼ each = 1 ¼ point
a. Chemicals that produce H+ ions in water are acids / bases (circle one)
Ex: HCl  _H+___ + _Cl____ hydrochloric acid
b. Chemicals that produce OH- ions in water are acids / bases (circle one)
Ex: NaOH  _Na___ + _OH-___ sodium hydroxide (lye)
c. Circle the compound(s) below that will become acid in water:
Acids will disassociate into one or more H+ ions in water; bases disassociate into
OH- ions in water; salts disassociate into cations and anions (Na+, Cl-)in water
KOH
H2SO4
NaCl
HNO3
d. How are salts formed? _salts disassociate into cations and anions when dissolved in
water; formed when cations and anions join together________________________
e. Complete the “Chemical Compound’ portion part of your ‘Chemical Reactions and
Compounds’ worksheet, now if you have not already done so.
3. Acid-Base Balance: The Concept of pH
a. Draw a simple pH scale below and place the following substances at the correct
places: bile, blood, saliva, spinal fluid, stomach juices, and urine. 1 point
b. Which of these substances is the most acidic?
_Stomach juices; saliva_ basic? _urine @8.0; bile, blood, spinal fluid__1/2 point___
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4. Maintaining pH: Buffer Systems
a. How does the body compensate for the intake of extremely acidic or alkaline foods?
_Buffers convert strong acids or bases into weak acids and bases__1/4 point______
A. Organic Compounds
1. Carbohydrates ¼ each = 3 points
a. Elements composed of: _C, H, O_________________________________________
b. Ratio of elements: approximately and usually 1:2:1
c. What three major groups are carbohydrates divided into based on size?
_monosaccharides, disaccharides, and polysaccharides_______________________
d. Which group(s) are the simple sugars? _monosaccharides and disaccharides_______
e. Which group(s) are the complex carbohydrates? _polysaccharides_______________
-Monosaccharides:
Monomer or building block of carbohydrates.
What is the primary function of glucose? _serve as source of chemical energy
for generating ATP to fuel metabolic reactions___________________________
Examples of monosaccharides: _glucose, ribose, deoxyribose_______________
-Disaccharides:
What do they consist of? and what type of bond holds them together?
_two monosaccharides joined covalently________________________________
What is lost when they are formed? and what is this type of reaction called?
_ formed through dehydration synthesis (water molecule lost)______________
-Polysaccharides:
What type of reaction forms them? and what are they composed of?
_Dehydration synthesis; tens or hundreds of monosaccharides______________
What type of reaction breaks down polysaccharides and disaccharides? and
what is added in order for this type of reaction to occur?
_Decomposition/hydrolysis-water is added to cut the molecules apart________
What is the main polysaccharide in the human body, where is it stored, and
what is its function?
_Glycogen; cells of the liver and skeletal muscles; when energy demands are
high it is broken down into glucose, when energy demands are low glucose is
built back up into glycogen___________________________________________
Humans cannot digest a plant polysaccharide called cellulose, so why would we
consume plants? _It provides bulk/roughage or fiber that helps feces move
through large intestine______________________________________________
2. Lipids a-g ¼ each = 1 ¾ points
a. Elements composed of: _C, H, O__________________________________________
b. Ratio of hydrogen to oxygen atoms smaller than in carbohydrates, thus fewer polar
covalent bonds and lipids are hydrophobic
c. What does it mean to be ‘hydrophobic’? _insoluble in water____________________
d. What is the most plentiful type of lipid in the human body? _triglycerides_________
e. What form of matter does the lipid in item ‘d’ above exhibit at room temperature?
_Either solids (fats) or liquids (oils)________________________________________
f. How much energy does this particular lipid store compared to proteins and
carbohydrates? _more than twice as much chemical energy per gram___________
g. What is adipose tissue? _Fat tissue_______________________________________
h. Draw and label the structure of a triglyceride molecule below, you do not need to
show every single atom…show the molecules it is composed of. 1 point
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Rest ¼ each = 3 points
i.
Fatty acids chains of triglycerides can be saturated, monounsaturated, or
polyunsaturated. Describe the basic structure of each type below and list examples
of products they are found in.
Saturated fats: _only single covalent bonds between fatty acid carbon atoms;
saturated with hydrogen atoms; Example(s): cocoa, palm and coconut oils_______
Monounsaturated fats: _one double covalent bond between two fatty acid carbons;
Example(s): olive oil, peanut oil___________________________________________
Polyunsaturated fats: _more than one double covalent bond between fatty acid
carbon atoms; Example(s): margarine, vegetable shortening____________________
j. How is the structure of a phospholipid different from that of a triglyceride?
_Glycerol with only two fatty acids instead of three___________________________
k. Below is a picture of a phospholipid cell membrane that has two layers arranged
nonpolar tail to nonpolar tail with the polar heads on the outer surfaces. The tails
are hydrophobic and the heads are hydrophilic, what important property does this
give to phospholipid bilayers(not in textbook, you’ll have to ponder)?
_Waterproofing and control of enters and leaves_____________________________
l. What is unique about the structure of steroids? _four rings of carbon atoms______
m. Which steroid can be synthesized by the human body into other steroids?
_cholesterol _________________________________________________________
n. What is estradiol? _one of the estrogens of female sex hormones______________
o. What is testosterone? _main male sex hormone____________________________
p. What other three types of steroids can be synthesized by the human body?
_cortisol, bile salts, and vitamin D________________________________________
3. Proteins a-b ¼ each = ½ point
a. Elements composed of: _C, H, O, N, and sometimes S________________________
b. What are the roles of proteins in the human body?
_acts as enzymes that speed up chemical reactions_____________________
_responsible for contractions of muscles_____________________________
_act as antibodies to help defend to body against invading microbes_______
_act as hormones or responsible for structure of body cells______________
c. Amino acids are the monomers or building blocks of proteins, label the three parts
of their structure (side chain, amino group, and carboxyl group) below: ½ point
Rest ¼ each =1 ½ points
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d. Which is the only part of the amino acid structure that varies from amino acid to
amino acid? _R-side chain______________________________________________
e. Describe what peptides, dipeptides, tripeptides, and polypeptides are below:
Peptides: _union or two or more amino acids_______________________________
Dipeptides: _name given to the molecule when two amino acids unite__________
Tripeptides: _Adding another amino acid to a dipeptide forms a tripeptide, now
three amino acids united_______________________________________________
Polypeptides: _contains three or more amino acids, large amount of amino acids__
f. What is denaturation? _if protein encounter hostile environments in which
temperature, pH, or ion concentration is significantly altered, it may unravel and
lose its characteristics, no longer functional________________________________
4. Enzymes ¼ each =1 ¼ points
a. What do enzymes do? _speed up chemical reactions by increasing the frequency of
collisions between molecules and by properly orienting the colliding molecules____
b. Enzymes are catalysts. What does this statement mean? _They are substances that
can speed up chemical reactions without being used up themselves or altered_____
c. List the three important properties of enzymes below and briefly explain each one:
(1). _Specificity: enzymes are specific in that each different type catalyzes particular
chemical reactions that involve specific substrates (molecules upon which the
enzymes act) and that they give rise to specific products (molecules produced by the
reaction). Enzymes fit the substrate like a lock-and-key fit one another or they
change shape to fit snugly around the substrate once the enzyme and substrate
come together; over 1000 types known each with a characteristic 3-D shape______
(2). _Efficiency: under optimal conditions(right temperature, pH, inhibitors,
concentration, genetics/PKU, chemical environment, cofactors/coenzymes),
catalyze at a rate of millions to billions of times more rapidly than would occur
without enzyme. Single enzyme produce molecules at rate of 600,000/second____
(3). _Control: subject to variety of cellular controls; i.e. rate of synthesis, their
concentration at any given time=>cells’ genes control this. Exist in active and
inactive forms, most require a cofactor or coenzyme to operate properly.
Cofactors=ions of iron, zinc, magnesium, or calcium. Coenzymes= niacin, riboflavin,
derivatives of B vitamins.________________________________________________
5. Nucleic Acids: Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA)
a. Elements composed of: _C, H, O, P, and N____1/4 point_______________________
b. Nucleotides are the monomers or building blocks of nucleic acids. In the table
below list the three parts of nucleotides found in DNA and RNA: 1 point
DNA;double helix
RNA;single strand
5-C sugar/deoxyribose
5-C sugar/ribose
4 nitrogenous bases= Adenine, Cytosine, 4 nitrogenous bases= Adenine, Cytosine,
Guanine, and Thymine
Guanine, and Uracil
Phosphate group
Phosphate group
c. We will discuss the functions of both of these molecules in detail in Chapter 3.
6. Adenosine Triphosphate ¼ each = 1 ¼ points
a. What is the main function of ATP? _’energy currency’ of the living organisms______
b. List some of its cellular activities below:
_transfer energy from energy-releasing reactions to energy-requiring reactions that
maintain cellular activities___________________________________________
_Activities include: contraction of muscles, movement of chromosomes during cell
division, movement of structures within a cell, transport of substances across cell
membrane, and synthesis of larger molecules from small ones__________________
c. What is adenosine composed of? _Adenine & ribose__________________________
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d.
What energy-transferring reaction releases energy from ATP? _hydrolysis_________
CHECKPOINT: 2 points each = 14 points
1. How do inorganic compounds differ from organic compounds? _ Inorganic compounds lack carbon,
are structurally simple, held together by ionic or covalent bonds; examples: water, many salts, acids,
bases, and two-carbon containing compounds, carbon dioxide (CO2 ) and bicarbonate ions (HCO3-)
_Organic compounds contain carbon, usually also contain hydrogen, always have covalent bonds;
examples: carbohydrates, lipids, proteins, nucleic acids, and adenosine triphosphate_
2. What functions does water perform in the body? _catabolic and anabolic reactions aided by it
(decomposition and synthesis reactions),excellent solvent, absorbs and releases heat very slowly as well
as requires a great deal of heat to change from liquid to gas thus aiding to maintain homeostasis, and
acts as a lubricant for and among body structures_____________________________________________
3. What is a buffer? _ a solution that resists changes in pH when acid or alkali is added to it. Buffers
typically involve a weak acid or alkali together with one of its salts_
4. Distinguish among saturated, monounsaturated, and polyunsaturated fats. _Saturated fats: _only
single covalent bonds between fatty acid carbon atoms; saturated with hydrogen atoms; Example(s):
cocoa, palm and coconut oils. Monounsaturated fats: _one double covalent bond between two fatty
acid carbons; Example(s): olive oil, peanut oil. Polyunsaturated fats: _more than one double covalent
bond between fatty acid carbon atoms; Example(s): margarine, vegetable shortening._
5. What are the important properties of an enzyme? _(1). _Specificity: enzymes are specific in that each
different type catalyzes particular chemical reactions that involve specific substrates (molecules upon
which the enzymes act) and that they give rise to specific products (molecules produced by the
reaction). Enzymes fit the substrate like a lock-and-key fit one another or they change shape to fit snugly
around the substrate once the enzyme and substrate come together; over 1000 types known each with
a characteristic 3-D shape_(2). _Efficiency: under optimal conditions (right temperature, pH, inhibitors,
concentration, genetics/PKU, chemical environment, cofactors/coenzymes), catalyze at a rate of millions
to billions of times more rapidly than would occur without enzyme. Single enzyme produce molecules at
rate of 600,000/second_(3). _Control: subject to variety of cellular controls; i.e. rate of synthesis, their
concentration at any given time=>cells’ genes control this. Exist in active and inactive forms, most
require a cofactor or coenzyme to operate properly. Cofactors=ions of iron, zinc, magnesium, or calcium.
Coenzymes= niacin, riboflavin, derivatives of B vitamins._
6. How do DNA and RNA differ?
DNA;double helix
5-C sugar/deoxyribose
4 nitrogenous bases= Adenine, Cytosine,
Guanine, and Thymine
Phosphate group
RNA;single strand
5-C sugar/ribose
4 nitrogenous bases= Adenine, Cytosine,
Guanine, and Uracil
Phosphate group
7. Why is ATP biologically important? _’energy currency’ of the living organisms_
Critical thinking applications: 2 points each for 2 = 4 points
1. While having a tea party, your three-year old cousin Sabrina added milk, lemon juice, and lots of
sugar to her tea. The tea now has strange white lumps floating in it. What caused the milk to
curdle?
ANS: the protein in the milk is denatured by the acid in the lemon juice.
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2. Joy is very proud of her healthy diet. “I drink only pure spring water and eat organic foods. I
have a chemical-free body.” Sonia replied, “Ever hear of H2O?” Explain the error in Joy’s
reasoning.
ANS: Human body composed of 26 elements; H2O over half the body’s mass
3. Albert Jr. was trying out the new Super Genius Home Chemistry Kit that he got for his birthday.
He decided to check the pH of his secret formula: lemon juice and diet cola. The pH was 2.5.
Next he added tomato juice. Now he had a really disgusting mix with a pH of 5. “Wow!” That’s
twice as strong!” Does Albert Jr., have the makings of a “Super Genius”? Explain.
ANS: Al Jr. does not understand pH. Each increase of one whole number on the pH scale
represents a 10-fold increase in H+ concentration. The pH of 5 is over 100 times less acidic or
over 100 times more alkaline than 2.5.
4. There’s been a mix up at the hospital. Little Dennis snuck into the nursery and cut off the babies’
identification bracelets. How can the hospital be sure to match the babies with the correct
parents using the information you learned in this chapter?
ANS: small tissue sample from each baby and parents for comparison; DNA fingerprinting
comparisons
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