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ACTIVITY 2-2. ORGANIC CHEMISTRY
Name
~
carbon bonds
Question
Date_____
All organic compounds contain carbon. The outer shell of the carbon atom
contains four electrons. In organic compounds, each carbon atom fills its
outer shell by sharing four pairs of electrons with other atoms. That is,
each carbon atom forms four covalent bonds. Some of these bonds may
form between one carbon atom and another. A framework of carbon-tocarbon bonds forms the basic structure in most organic compounds. A
carbon atom may be joined to another atom by a single bond, a double
bond, or a triple bond.
The following structural formulas show three different compounds of carbon and hydrogen.
Below each structural formula, write the empirical formula for that compound. Label the double
and triple bonds in these structures.
Ii’
H—C~C—H
H—C=C—H
H_?_lf_H
RH
t
Ct~Jq
—
Carbohydrates are organic compounds composed of carbon, hydrogen,
carbohydrates and
oxygen. The proportion of hydrogen atoms to oxygen atoms in carbohydrates is the same as in water—two hydrogens to one oxygen. There
are three basic types of carbohydrates—monosaccharides, disaccharides,
and polysaccharides.
mono-Monosaccharides, or simple sugars, are the least complicated carbohydrates. In biology the three most common simple sugars are glucose,
saccharides galactose, and fructose. These three sugars all have the same empirical
formula (C6H1206), but their atoms are arranged differently (see below).
H
GALACTOSE
FRUCTOSE
‘3 LLJCOSE
H
H—C—OH
H—C—OH
H—C—OH
/H
~
H/~OH
H/ \?H
~
t/ ~C-OH
Questions
1. In what way do glucose and gaiactose differ from each other? Circle the parts of both compounds that show this difference,
2. Another name for &ucose is /iiO/~oça~~ha r~ic.
&‘~~)li~y:2(t
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3. The simplest possible formula that illustrates the proportion of elements in monosaccharides
is
25
dehydration
synthesis
and hydrolysis
Carbohydrates, proteins, and lipids are all synthesized and broken down
by the same types ofreactions. In dehydration synthesis, a hydrogen atom
from one molecule joins with a hydroxyl group from another molecule to
form water, leaving the two molecules bonded to the same oxygen atom.
For example, when two molecules of glucose are joined by dehydration
synthesis, they form maltose and water (see below).
In hydrolysis, complex organic molecules are broken down by the addition of the components of water
H’4- and OH-. Both dehydration synthesis and hydrolysis require certain conditions of pH and temperature
and the presence of particular enzymes.
—
H
H
H—C—OH
H
H—C--OH
H
H—C—OH
H—C—OH
0
H
H
OH
Glucose
+
OH
H
OH
Glucose
‘-
OH
Maltose
Water
+
Questions
1. In the space below show the hydrolysis of maltose. (The reaction is the reverse of the
dehydration synthesis of maltose.)
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k
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a
p
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2. What are the products of the hydrolysis of maltose?
3. In what life process does hydrolysis occur?
28
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___________
When two monosaccharides combine, they form a disaccharide. .A disac.
can consist either of two molecules of the same simple sugar
combined or of two different simple sugars combined. Some common
disaccharides are maltose, sucrose, and lactose.
-
disaccharIdes charide
m
tO
n.
Questions
nre
I. Name the monosaccharides that make up the following disaccharides:
C/
,.
maltose:
sucrose
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2. What is the empirical formula for maltose, sucrose, and lactose?
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3. Why is the empirical formula not double that of the monosaccharides?
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4.
What are the common names for sucrose and lactose?
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The most complex carbohydrates are the polysaccharides, which are made
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po ysacc ar e up of long chains of glucoselike units. Starch, cellulose, and glycogen are
and polymers polysaccharides. Large molecules made up ofchains ofrepeating units are
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called polymers. Polysaccharides, such as the ones mentioned above, are
polymers.
Questions
I. What substance is the repeating unit that makes up starch, cellulose, and glycogen?
a
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t/~~
2. Starch, cellulose, and glycogen are all made up of the same repeating unit. In what way do
these three substances differ from one another?
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3. Name another type 4
of compound (beside polysaccharides) that fits the definition of a polymer.
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Lipids
a group oforganic
compounds
oils, waxes,
and
related are
substances.
Lipids are
composedthat
of include
carbon, fats,
hydrogen,
and oxygenobut there is no definite ratio of hydrogen to oxygen atoms in lipids as
there is in carbohydrates. Simple lipids, which are the most common type,
are made up of three fatty acid molecules and one glycerol molecule.
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27
r
Questions
1. Label each of the components in the equation below. What type of reaction is shown in the
equation?
H
0
II
0
H— ~—~o~”~o—
~
C~H31
r-~
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9
H— C—LOH +
I-C—c
I
9
—
____
—
C15H31
~‘
H—C-—0—C—C15H31
+
3H20
o
H_C_ILOHMO_
3
(~
H—C—-0-4—C15H31
C15H31
—
cC4
EArn, hc/4):s
2. What type of compound is glycerol? ~
3. Write the empirical formula for fatty acids.
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4. What is the difference between a saturated and an~ saturate fatty acid?
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rote in
Questions
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Proteins
typemolecules
of organic
compound
in cells.
They
are madeare
upthe
of most
manyabundant
amino acid
bonded
together.
Proteins,
which may be very large and complex, play a wide variety of roles in the
cell. Some are structural, others are hormones, neurohumors, enzymes, or
pigments.
Amino acids are made up of carbon, hydrogen, oxygen, and nitrogen;
some also contain sulfur. Amino acids are bonded together to form proteins by dehydration synthesis. The type of bond formed between amino
acids is called a peptide bond. It involves a carboxyl group from one
molecule and an amino group from the other.
1. Name three foods that are high in protein.
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2. Below is the general formula for an amino acid. Circle the amino group and the carboxyl
group.
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H
3. Using the general formula foramino acids, in the space below show the formation of a peptide
bond.
A
*3/
a
.
p
—
C
T
28
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(
Maine
4.
Class
Date
___________
___________
,...._.—~
What does the R represent in the general fonnuia for amino acids?
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5. If the R is a hydrogen atom, what amino acid is formed?
6. If the R is a methyl group (CH3), what amino acid is formed?
ALAN! ,W4-E
Enzymes are proteins that act as catalysts in living cells. A catalyst increases the rate of a chemical reaction, allowing it to proceed rapidly when
it would otherwise occur only very slowly. Enzymes are highly specific in
their catalytic activity. The specificity of enzyme action is the result of a
“lock-and-key” arrangement in which the enzyme and the substance it
reacts with (the substrate) join together to form an enzyme-substrate complex. When the reaction is completed, the enzyme and the newly formed
reaction products separate, leaving the enzyme unchanged. Enzymes are
highly efficient catalysts, and only small quantities are needed to catalyze
the reaction of relatively large amounts of materials. Each enzyme has an
optimum range of temperature and pH at which it operates most efficiently.
enzymes
hey
ins,
the
,or
Iromo
ne
Questions
I. Is an enzyme “used up” by the reaction it catalyzes? Explain.
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2. In what way does an enzyme affect the reaction it catalyzes? How does the enzyme produce
this effect?
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3. What is meant by enzyme specificity?
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4. What is the active site of an enzyme?
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5. The substance with which an enzyme reacts is its
a
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6, Could life as we know it exist without enzymes? Explain.
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A
I
0
10
I
20
30
405060
Temperature{°C)
C
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pH
D
CE
mc
Enzyme concentration
—
Substrate concentration
Questions 7-10 are based on the graphs above.
7. According to graph A, at what temperature is enzyme activity the greatest?
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37°c
According to graphB, what is the optimum pH for pepsin? As pH increases above that point,
what happens to enzyme activity?
A,
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9. According to graph C, how does increasing enzyme concentration affect the rate of enzyme
action when the substrate concentration remains constant?
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10. According to graph D, how does increasing substrate concentration affect the rate of enzyme
action when enzyme concentration remalns constant?
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8.
D
nucleic acids
There are two types of nucleic acids found in living organisms—DNA
(deoxyribonucleic acid) and RNA (ribonucleic acid). Both are giant
molecules of high molecular weight, consisting of a series of nucleotide
units bonded together. Each nucleotide consists of a five-carbon sugar
bonded to a nitrogen base and a phosphate group. DNA contains the
hereditary information, while RNA functions in protein synthesis.
Questions
I, What are the three basic components of the nucleotides that make up nucleic acids?
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2. Where is DNA found in the cell?
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3. Describe the basic functions of DNA.
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4, Describe the basic functions of RNA.
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3:
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Nam.
Clue__________ Oat.__________
REVIEW EXERCISES~UNIT 2
-
A. Using the vocabulary terms in the following list, fill in the blanks in the statements below.
atom
atomic number
carbohydrate
colloid
compound
covalent bonding
dehydration synthesis
disaccharide
electron
element
hydrolysis
ionic bonding
isotope
lipid
mass number
mixture
monosaccharide
neutron
nucleic acid
nucleus
pH
polymer
polysaccharide
protein
proton
radioactive decay
radioactivity
solution
suspension
I. A material with definite properties and definite chemical composition is a
E~e’~~t
NC
-
2. A substance that cannot be broken down into other substances by ordinary chemical means
isa(n)
4YdAi
3. A substance formed by the chemical combination of two or more elements is a(n)
4.
t
4J4/’ \
The basic unit of structure of all elements is the
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5. Atoms are made up of three types of particles:
/3
/
,and
6. The dense central portion of the atom is the
A-’ ~?t( 3:494/5
7. The number of protons in the nucleus of its atoms is the
4.-r9ps~:
,VpJA1t~
of an element.
8. The number of protons plus the number oi neutrons in the nucleus of an atom is its
frn4c( /1
9. Different varieties of the same element having different numbers of neutrons in their nuclei
are called __________________________
10. The breakdown of an unstable isotope to an isotope of another element with the release of
radiation is called
or
714P4. /
)fr~7 9
..
7/
~:
/.N
./\~//?
/3
11. Chemical bonding in which there is a transfer of electrons from one atom to another is
Fi C.
c~.
12. Chemical bonding in which there is a sharing of electrons between atoms is
31
13. Measurement of the hydrogen ion concentration of a solution may be given in terms of
14. A purely physical association of substances is a /4,
15. Three types of mixtures are
~j~1~{ /34
and
yi~•2#’e’3’•
_____________________________
________________________
_________________________
16. The four most important types of organic compounds found in living cells are
9a..~
041/4
flLk. C, t.7’C Pt 3: .S
( p Pt
and
17. Glucose is a
_______________
5i
((4/49
; maltose is a
and starch is a
f2b
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-4/
4v1/~.~
18. The type of reaction by which proteins are synthesized is
19. The type of reaction by which carbohydrates are broken down is
cc
20. Large molecules made up of chains of repeating units are
B. Place the letter of the definition in the space to the left of the term it defines.
I~k 1. amino acids
A. Type of reaction by which complex molecules are
C 2. enzymes
synthesized from simple molecules.
—
B. A substance composed of similar repeating units.
~
3. nucleic acids
• C. Proteins that act as organic catalysts.
4. unsaturated fat
D. Digestion is accomplished by this type of reaction.
.
—~
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5. amino group
41
6. hydrolysis
7. carboxyl group
______
8. dehydration synthesis
9. glycerol
19
,_it...10. polymer
_______
_______
E. COOH
F. RNA and DNA
G. Alcohol found in lipids.
H. Units of which proteins are composed.
I. A lipid containing carbon atoms with double bonds
between them.
.1.
iMfl
2
C. In the answer space for each question, write the letter of the choice that best completes the
statement.
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‘
The unit of structure of all elements is the (a) neutron (b) atom (c) proton (d)
electron
2. The mass number of an atom is (a) the number of protons in the nucleus (b) the
number of neutrons in the nucleus (c) the number of protons plus the number of
neutrons in the nucleus (d) the number of electrons in the nucleus
3. Isotopes of the same element differ from one another in the (a) number of protons in
the nucleus (b) number of neutrons in the nucleus (c) number of electrons (d)
location of electrons
32
Name
Class
_—~—~
____________
--
Date
____________
____________
4, Chemical bonds in which electrons are shared between atoms are called (a) ionic
(b) covalent (c) divalent (d) electronic
5. Chemical bonds in which there is a transfer of electrons from one atom to another are
called (a) ionic (b) covalent (c) divalent (d) electronic
6, A pH of? indicates a (a) strong acid (b) strong base (c) neutral solution (d) weak
base
,.,....L. 7. Organic compounds always contain (a) oxygen (b) proteins (c) nitrogen (d)
carbon
8. Carbohydrates are composed of (a) carbon, nitrogen, and oxygen (b) nitrogen,
oxygen, and hydrogen (c) carbon, hydrogen, and oxygen (d) sulfur, nitrogen, and
carbon
9. Glucose and fructose are both
_____
are
r
‘
4
_______
A
ids
_______
(a) monosaccharides
(b) disaccharides
(c)
polysaccharides (d) starches
Maltose and sucrose are both (a) monosaccharides (b) disaccharides (c)
polysaccharides (d) starches
Monosaccharides join to form disaccharides by (a) hydrolysis (b) hydration (c)
dehydration synthesis (d) dehydrolysis
12. Disaccharides are broken down into their component monosaccharides by (a) hydrolysis (b) hydration (c) dehydration synthesis (d) dehydrolysis
13. Cellulose and glycogen are (a) proteins (b) fatty acids (c) polysaccharides (d)
disaccharides
14. Simple lipids consist of (a) three fatty acid molecules and one glycerol (b) fatty
acids only (c) glycerol only (d) amino acids
15. The bonds between amino acids in proteins are (a) peptide bonds (b) unsaturated
(c) hydrolytic (d) carboxylic
16. Enzymes are (a) carbohydrates (b) lipids (c) proteins ~ hormones
1.’. Enzymes (a) decrease reaction rates (b) increase reaction rates (c) are involved
only in synthetic reactions (d) are involved only in hydrolytic reactions
18. Nucleic acids are composed of (a) a nitrogen base, five-carbon sugar, and phos-
1?
“
phate (b) a nitrogen base, six-carbon sugar, •and phosphate group (c) a nitrogen
base, five-carbon sugar, and carboxyl group (d) a nitrogen base, phosphate group,
and glucose
19. DNA (a) is the site of protein synthesis (b) contains the hereditary information (c)
is found only in the cytoplasm (d) is found only in animal cells
.__izc...20. RNA is involved in (a) lipid synthesis (b) carbohydtate synthesis (c) protein synthesis (d) DNA synthesis
33
PUZZLE: UNIT 2
Across
I. Number of protons in nucleus is
number.
3. Glucose is a simple
8. Proteins are made up of
acids.
9. Positively charged particles found in nucleus.
11. Substance that cannot be broken down by ordinary chemical reactions.
12. Type of chemical bond in which electrons are shared.
IS. Number of protons plus neutrons in nucleus is
number.
16. Substances formed by chemical combination of two or more elements.
17. Type of reaction by which proteins and carbohydrates are broken down.
19. Negatively charged particles found outside nucleus.
________
________
Down
2. Element that rusts.
4, Substance with pH of 2 is strong
5. Substance made up of three fatty acid molecules and one glycerol molecule.
6. Homogeneous mixtures of two or more substances that do not settle on standing.
7. Substances in which particles larger than those of solutions are dispersed within a medium.
10. NaCI is common table
II. Proteins that act as catalysts within cells.
13. Basic units of structure of elements.
14. Type of bond in which there is a transfer of electrons.
18. Atom or group of atoms with electrical charge.
34