Unit 2 Study Guide
Biomolecules, Enzymes, Digestive System
1) Water is classified as an inorganic compound because it does not contain ________________
2) A chemical analysis of organisms from each kingdom shows that living things are primarily composed of
the elements
3) Luciferin is a molecule that, when broken down in fireflies, produces heat and light. The rate at which
luciferin is broken down in cells is controlled by
4) Which statement about enzymes is not correct?
A)
B)
C)
D)
Enzymes are composed of polypeptide chains.
Enzymes form a temporary association with a reactant.
Enzymes are destroyed when they are used and must be synthesized for each reaction.
Enzymes are specific because of their shape and catalyze only certain reactions.
5) Base your answer to the following question on Hydrogen peroxide (H 2O2) is a toxic by-product of cellular
metabolism in aerobic organisms. The reaction below occurs within the cells to prevent the accumulation of
hydrogen peroxide.
In this reaction, catalase functions as an
6) Base your answer to the following question on The graph below shows the results of an action of the
enzyme catalase on a piece of meat. Evidence of enzyme activity is indicated by bubbles of oxygen.
What is the optimal temperature for catalyase activity?
7) Meat tenderizer contains an enzyme that interacts with meat. If meat is coated with tenderizer and then
placed in a refrigerator for a short time, how would the enzyme be affected?
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8) The graph below shows the effect of temperature on the relative rate of action of enzyme X on a protein.
Which change would not affect the relative rate of action of enzyme X?
A)
B)
C)
D)
the addition of cold water when the reaction is at 50°C
an increase in temperature from 70°C to 80°C
the removal of the protein when the reaction is at 30°C
a decrease in temperature from 40°C to 10°C
9) The enzyme amylase will affect the breakdown of carbohydrates, but it will not affect the breakdown of
proteins. The ability of an enzyme molecule to interact with specific molecules is most directly determined
by the
10) Base your answer to the following question on the diagram below, which represents a chemical reaction
that occurs in the human body, and on your knowledge of biology.
Substances X and Y are examples of which kind of molecule?
11) Which compound is a polysaccharide?
A) glucose
B) maltase
C) ribose
D) starch
12) More energy can be released from a fat molecule than from a glucose molecule because the fat molecule
contains more
13) Which organic compound is produced when three fatty acid molecules bond to one glycerol molecule?
14) In living organisms, lipids function mainly as
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15) Vegetable oils, such as corn oil, belong to which general class of organic substances?
16) The way a protein molecule is folded determines the shape of the molecule, which determines the
17) The shape of a protein is originally determined by the
18) Base your answer to the following question on Three structures are represented in the diagram below.
What is the relationship between these three structures?
19) The digestion of starch begins in the
20) Base your answer to the following question on The diagram below represents a portion of the human body.
The principal function of structure X is to
21) In humans, structures that absorb most of the products of digestion are the
22) Choking on food is most likely caused by an interference with the proper functioning of the
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23) Which structure produces a substance that aids in the mechanical breakdown of fats?
24) In humans, structures that release digestive secretions directly into the small intestine include both the
25) Base your answer to the following question on the diagram below. For each statement select the organ, that
is most closely associated with the statement below. [A number may be used more than once or not at all.]
label each organ above with the name of the structure and its function..
26) Within which structure of an animal cell does DNA replication take place?
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27) Base your answer to the following question on the diagram below. For each of the following phrases, select
the molecule, chosen from those shown below, which is best described by that phrase.
Label the above molecules (lipid, carbohydrates, water, amino acid, and proteins)
28) Which substance is an inorganic molecule?
A) starch
B) DNA
C) water
D) fat
29) Which statement describes all enzymes?
A)
B)
C)
D)
They control the transport of materials.
They provide energy for chemical reactions.
They affect the rate of chemical reactions.
They absorb oxygen from the environment.
30) The sweet taste of freshly picked corn is due to the high sugar content in the kernels. Enzyme action
converts about 50% of the sugar to starch within one day after picking. To preserve its sweetness, the
freshly picked corn is immersed in boiling water for a few minutes, and then cooled.
Which statement most likely explains why the boiled corn kernels remain sweet?
A)
B)
C)
D)
Boiling destroys sugar molecules so they cannot be converted to starch.
Boiling kills a fungus on the corn that is needed to convert sugar to starch.
Boiling activates the enzyme that converts amino acids to sugar.
Boiling deactivates the enzyme responsible for converting sugar to starch
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Base your answers to questions 31 and 32 on the graph below and your knowledge of biology.
31) Neither enzyme works at a pH of
A) 1
B) 5
C) 3
D) 13
32) Pepsin works best in which type of environment?
A) acidic, only
C) neutral
B) basic, only
D) sometimes acidic, sometimes basic
33) Base your answer to the following question on the graph below and on your knowledge of biology. The
graph shows the relative rates of action of four enzymes, A, B, C, and D.
Which two enzymes would function in a region of the human body having a neutral pH?
A) A and B
B) B and C
C) C and D
D) B and D
34) In the enzyme-controlled reaction represented by the word equation below, which molecules are
considered the substrate?
monosaccharide + monosaccharide ® disaccharide + water
A) monosaccharide and monosaccharide
C) monosaccharide and water
B) disaccharide and water
D) monosaccharide and disaccharide
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35) Base your answer to the following question on In the reaction illustrated in the diagram below, which
structure represents the enzyme?
A) A
B) B
C) C
D) D
36) Base your answer to the following question on the information below and on your knowledge of biology.
Organisms living in a bog environment must be able to tolerate nitrogen-poor, acidic
conditions. Bog plants such as the Venus flytrap and sundew are able to obtain their nitrogen
by attracting and consuming insects. These plants produce chemicals that break down the
insects into usable compounds.
Which compounds present in insects are composed of the amino acids that provide the Venus flytrap and
sundew with much of their nitrogen?
A) proteins
B) sugars
C) carbohydrates
D) fats
Base your answers to questions 37 through 40 on the information below and on your knowledge of
biology.
Where is the Beef? Out Being Irradiated E. coli bacteria in food cause an estimated 73,000 cases of infection leading to some deaths in the
United States each year. Until recently, the only way to guarantee meat free of E. coli was to heat it to
160°F, which kills E. coli. The rare hamburgers preferred by many people are not heated to this
temperature, and just a few E. coli may cause severe illness.
Recently, ground beef has been decontaminated by irradiation using electron beam technology. The
packaged ground beef is scanned by an electron beam that disrupts the genetic structure of the
pathogens. This kills them or leaves them unable to reproduce.
This process is considered safe and has been endorsed by various governmental groups in this
country as well as the World Health Organization. Irradiation is effective in preserving only certain
foods, such as herbs, wheat flour, fresh fruits, vegetables, and some meats. Although some methods of
irradiation can change the taste of some foods, this is not an effect of electron beam technology on
ground beef.
Opponents of irradiating food are concerned that the process may result in the formation of
chemicals that may be harmful or result in a loss of vitamins. Supporters claim that irradiation is safe
and should be considered as just another technique for preservation of food.
37) Explain how irradiation could interfere with the process of reproduction in bacteria that survive the
irradiation.
38) Explain how irradiation helps preserve meat.
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39) Identify the specific group of molecules in bacteria whose function would be interfered with by heating
them to 160°F.
40) Identify one specific pathogen found in ground beef.
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Base your answers to questions 41 through 44 on the information below and on your knowledge of
biology.
Hydrogen peroxide is a toxic substance produced in an organism as a result of certain metabolic processes.
Catalase, a biological catalyst produced by cells, speeds the breakdown of hydrogen peroxide into less
harmful substances.
In an investigation, 2-gram pieces of liver (which contains catalase) were added to separate dishes. Each
dish contained the same amount of a 3% solution of hydrogen peroxide, but at different temperatures. The
relative activity of the catalase was determined. The results were recorded and are shown in the data table
below.
41) Plot the data, surround each point with a small circle, and connect the points
42) What type of organic substance is catalase?
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43) At which temperature does catalase work most effectively? Support your answer.
44) Mark an appropriate scale on each axis