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All the organisms on your campus make up
Which of the following is a correct sequence of levels in life’s
hierarchy, proceeding downward from an individual animal?
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an ecosystem.
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a community.
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a population.
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a taxonomic domain.
Frage 2
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Which of the following is a correct sequence of levels in life’s
hierarchy, proceeding downward from an individual animal?
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organism, brain, organ system, nerve cell
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organ system, nervous tissue, brain, nerve cell
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organism, organ system, tissue, cell, organ
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nervous system, brain, nervous tissue, nerve cell
Frage 3
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Which of the following correctly list the levels of biological organization from largest to smallest?
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Organelles → Cells → Tissues → Organs & Organ Systems → Organisms → Populations → Communities → Ecosystems → Biosphere
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Cells → Tissues → Organelles → Organs & Organ Systems → Organisms → Populations → Communities → Ecosystems → Biosphere
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Biosphere → Ecosystems → Communities → Populations → Organisms → Organs & Organ Systems → Tissues → Molecules → Cells → Organelles
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Biosphere → Ecosystems → Populations → Communities → Organisms → Organs & Organ Systems → Tissues → Molecules → Cells → Organelles
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Biosphere → Ecosystems → Populations → Communities → Organisms → Organs & Organ Systems → Organelles → Molecules → Tissues → Cells
Frage 4
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In the term trace element, the adjective trace means that
Antworten
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the element is required in very small amounts.
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the element can be used as a label to trace atoms through
an organism’s metabolism.
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the element is very rare on Earth.
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the element enhances health but is not essential for the organism’s
long-term survival.
Frage 5
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Compared with 31 P, the radioactive isotope 32 P has
Frage 6
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The reactivity of an atom arises from
Antworten
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the average distance of the outermost electron shell from
the nucleus.
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the existence of unpaired electrons in the valence shell.
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the sum of the potential energies of all the electron shells.
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the potential energy of the valence shell.
Frage 7
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Which statement is true of all atoms that are anions?
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The atom has more electrons than protons.
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The atom has more protons than electrons.
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The atom has fewer protons than does a neutral atom of the
same element.
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The atom has more neutrons than protons.
Frage 8
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Which of the following statements correctly describes any
chemical reaction that has reached equilibrium?
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The concentrations of products and reactants are equal.
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The reaction is now irreversible.
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Both forward and reverse reactions have halted.
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The rates of the forward and reverse reactions are equal.
Frage 9
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We can represent atoms by listing the number of protons,
neutrons, and electrons—for example, 2p + , 2n 0 , 2e - for helium.
Which of the following represents the 18 O isotope of oxygen?
Antworten
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7p + , 2n 0 , 9e -
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8p + , 10n 0 , 8e -
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9p + , 9n 0 , 9e -
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10p + , 8n 0 , 9e -
Frage 10
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The atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur
atom, predict the molecular formula of the compound.
Frage 11
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What coefficients must be placed in the following blanks so
that all atoms are accounted for in the products?
C 6 H 12 O 6 -----> ____ C 2 H 6 O + ____ CO 2
Frage 12
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Draw Lewis dot structures for each hypothetical
molecule shown below, using the correct number of valence
electrons for each atom. Determine which molecule makes
sense because each atom has a complete valence shell and each
bond has the correct number of electrons. Explain what makes
the other molecules nonsensical, considering the number of
bonds each type of atom can make. (which is wrong)
Frage 13
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We can be sure that a mole of table sugar and a mole of vitamin
C are equal in their
Antworten
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Mass
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Volume
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Number of Atoms
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Number of Molecules
Frage 14
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Measurements show that the pH of a particular lake is 4.0.
What is the hydrogen ion concentration of the lake?
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4.0 M
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10^ (-10) M
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10^ (-4) M
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10^ (4) M
Frage 15
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What is the hydroxide ion concentration of the lake described
in question 3 (pH of a particular lake is 4.0)?
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10^(-10) M
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10^(-4) M
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10^(-7) M
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10.0 M
Frage 16
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A slice of pizza has 500 kcal. If we could burn the pizza and use
all the heat to warm a 50-L container of cold water, what would
be the approximate increase in the temperature of the water?
(Note: A liter of cold water weighs about 1 kg.)
Frage 17
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Draw the hydration shells that form around a potassium
ion and a chloride ion when potassium chloride (KCl)
dissolves in water. Label the positive, negative, and partial
charges on the atoms.
The image below correctly display this.
Frage 18
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QUESTION:
In agricultural areas, farmers pay close attention to the weather
forecast. Right before a predicted overnight freeze, farmers
spray water on crops to protect the plants. Use the properties
of water to explain how this method works. Be sure to mention
why hydrogen bonds are responsible for this phenomenon.
ANSWER:
Due to intermolecular hydrogen bonds, water has a [blank_start]high[blank_end] specific heat (the
amount of heat required to increase the temperature of water by 1°C). When water
is heated, much of the heat is absorbed in [blank_start]breaking[blank_end] hydrogen bonds before the
water molecules increase their motion and the temperature increases. Conversely,
when water is cooled, many H bonds are [blank_start]formed[blank_end], which [blank_start]releases[blank_end] a significant
amount of heat. This [blank_start]release[blank_end] of heat can provide some protection against freezing
of the plants’ leaves, thus protecting the cells from damage.
Antworten
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high
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low
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breaking
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forming
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formed
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broken
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releases
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absorbs
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release
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absorbsion
Frage 19
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Which functional group is not present in this molecule?
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Carboxyl
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sulfhydryl
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hydroxl
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amino
Frage 20
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Which of the following hydrocarbons has a double bond in its
carbon skeleton?
Frage 21
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Which chemical group is most
likely to be responsible for an organic molecule behaving as a
base
Antworten
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hydroxyl
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amino
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carbonyl
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phosphate
Frage 22
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Which action could produce a carbonyl group?
Antworten
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the replacement of the —OH of a carboxyl group with
hydrogen
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the addition of a thiol to a hydroxyl
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the addition of a hydroxyl to a phosphate
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the replacement of the nitrogen of an amine with oxygen
Frage 23
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Which of the following categories includes all others in the
list?
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monosaccharide
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polysaccharide
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starch
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carbohydrate
Frage 24
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The enzyme amylase can break glycosidic linkages between
glucose monomers only if the monomers are in the α form.
Which of the following could amylase break down?
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glycogen, starch, and amylopectin
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glycogen and cellulose
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cellulose and chitin
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starch, chitin, and cellulose
Frage 25
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Which of the following is true of unsaturated fats?
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They are more common in animals than in plants.
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They generally solidify at room temperature.
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They have double bonds in the carbon chains of their fatty
acids.
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They contain more hydrogen than do saturated fats having
the same number of carbon atoms.
Frage 26
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The structural level of a protein least affected by a disruption
in hydrogen bonding is the
Antworten
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primary level.
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secondary level.
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tertiary level.
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quaternary level.
Frage 27
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Enzymes that break down DNA catalyze the hydrolysis of the
covalent bonds that join nucleotides together. What would
happen to DNA molecules treated with these enzymes?
Antworten
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The two strands of the double helix would separate.
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The phosphodiester linkages of the polynucleotide backbone
would be broken.
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The pyrimidines would be separated from the deoxyribose
sugars.
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All bases would be separated from the deoxyribose sugars.
Frage 28
Frage 29
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Which of the following pairs of base sequences could form a
short stretch of a normal double helix of DNA?
Antworten
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5′-AGCT-3′ with 5′-TCGA-3′
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5′-GCGC-3′ with 5′-TATA-3′
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5′-ATGC-3′ with 5′-GCAT-3′
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All of these pairs are correct.
Frage 30
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Which structure is not part of the endomembrane system?
Antworten
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nuclear envelope
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chloroplasts
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Golgi apparatus
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plasma membrane