Modified True/False
Indicate
whether the sentence or statement is true or false. If false, change the identified word or
phrase to make the sentence or statement true.
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1.
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When
Mendel crossed purebred short plants with purebred tall plants, all of the offspring were
short. _________________________
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2.
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A pea
plant that is heterozygous for tall stems has the alleles Tt.
_________________________
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3.
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An
organism’s physical appearance is its phenotype. _________________________
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4.
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The
sex cells produced by meiosis have twice the number of chromosomes as the parent cells.
_________________________
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Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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5.
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What
did Gregor Mendel do to study different characteristics in his genetics experiments? a. | He studied only
asexual animals. | b. | He studied only self-pollinating
plants. | c. | He cross-pollinated plants. | d. | He
cross-pollinated animals. | | |
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6.
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In
Mendel’s experiments, what proportion of the plants in the F2 generation had a trait
that had been absent in the F1 generation? a. | none | b. | one fourth | c. | half | d. | three fourths | | |
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7.
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Factors that control traits are called a. | genes. | b. | purebreds. | c. | recessives. | d. | parents. | | |
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8.
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Scientists call an organism that has two different alleles for a trait
a a. | hybrid. | b. | trait. | c. | purebred. | d. | factor. | | |
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9.
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What
does the notation TT mean to geneticists? a. | two dominant alleles | b. | two recessive
alleles | c. | at least one dominant allele | d. | one dominant and
one recessive allelle | | |
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10.
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What
does the notation Tt mean to geneticists? a. | two dominant alleles | b. | two recessive
alleles | c. | at least one recessive allele | d. | one dominant
allele and one recessive allelle | | |
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11.
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What
is probability? a. | the actual
results from a series of events | b. | the likelihood that a particular event will
occur | c. | the way the results of one event affect the next
event | d. | the number of times a coin lands heads
up | | |
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12.
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What
did Mendel predict was the probability of producing a tall plant from a genetic cross of two hybrid
tall plants? a. | one in
four | b. | two in
four | c. | three in
four | d. | four in
four | | |
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13.
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What
does a Punnett square show? a. | all the possible outcomes of a genetic
cross | b. | only the dominant alleles in a genetic
cross | c. | only the recessive alleles in a genetic
cross | d. | all of Mendel’s discoveries about genetic
crosses | | |
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14.
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If a
homozygous black guinea pig (BB) is crossed with a homozygous white guinea pig (bb),
what is the probability that an offspring will have black fur? a. | 25
percent | b. | 50 percent | c. | 75
percent | d. | 100 percent | | |
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15.
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An
organism’s physical appearance is its a. | genotype. | b. | phenotype. | c. | codominance. | d. | heterozygous. | | |
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16.
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What
does codominance mean in genetics? a. | Both alleles are dominant. | b. | Both alleles are
recessive. | c. | The alleles are neither dominant nor
recessive. | d. | Each allele is both dominant and
recessive. | | |
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17.
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What
happens during meiosis? a. | Each sex cell loses half of its
chromosomes. | b. | Chromosome pairs separate to form new sex
cells. | c. | Each sex cell copies itself to form four new
chromosomes. | d. | Chromosome pairs remain together when new sex cells are
formed. | | |
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18.
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When
sex cells combine to produce offspring, each sex cell will contribute a. | one fourth of
the normal number of chromosomes. | b. | half the normal number of
chromosomes. | c. | the normal number of chromosomes. | d. | twice the normal
number of chromosomes. | | |
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19.
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What
is the genetic code? a. | the order of nitrogen bases along a
gene | b. | the number of
nitrogen bases in a DNA molecule | c. | the order of amino acids in a protein | d. | the number of
guanine and cytosine bases in a chromosome | | |
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20.
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What
does messenger RNA do during protein synthesis? a. | copies the coded message from the DNA and carries it into the
cytoplasm | b. | copies the coded message from the DNA and carries it into the
nucleus | c. | carries amino acids and adds them to the growing
protein | d. | copies the coded message from the protein and carries it into
the nucleus | | |
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21.
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What
do transfer RNA molecules do during protein synthesis? a. | copy the coded
message from the protein and carry it into the nucleus | b. | copy the coded
message from the DNA and carry it into the nucleus | c. | carry amino
acids and add them to the growing protein | d. | copy the coded message from the DNA and carry it into the
cytoplasm | | |
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22.
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What
is a mutation? a. | any change that
is harmful to an organism | b. | any change in a gene or chromosome | c. | any change that
is helpful to an organism | d. | any change in the phenotype of a cell | | |
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23.
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A
mutation is harmful to an organism if it a. | changes the DNA of the organism. | b. | changes the
phenotype of the organism. | c. | reduces the organism’s chances for survival and
reproduction. | d. | makes the organism better able to avoid
predators. | | |
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24.
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The
different forms of a gene are called a. | alleles. | b. | factors. | c. | masks. | d. | traits. | | |
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25.
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Where
does protein synthesis take place? a. | in the ribosomes in the nucleus of the
cell | b. | on the ribosomes
in the cytoplasm of the cell | c. | in the chromosomes in the nucleus of the
cell | d. | on the
chromosomes in the cytoplasm of the cell | | |
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26.
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What
does the notation tt mean to geneticists? a. | two dominant alleles | b. | two recessive
alleles | c. | at least one dominant allele | d. | one dominant and
one recessive allelle | | |
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27.
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An
organism’s genotype is its a. | genetic makeup | b. | feather
color | c. | physical appearance | d. | stem
height | | |
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28.
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Which
nitrogen base in RNA is NOT part of DNA? a. | adenine | b. | guanine | c. | cytosine | d. | uracil | | |
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29.
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An
organism that has two identical alleles for a trait is a. | codominant. | b. | tall. | c. | homozygous. | d. | heterozygous. | | |
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30.
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A
heterozygous organism has a. | three different alleles for a trait. | b. | two identical
alleles for a trait. | c. | only one allele for a trait. | d. | two different
alleles for a trait. | | |
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Completion
Complete each sentence or
statement.
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31.
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The
offspring of a ____________________ plant will always have the same alleles for a trait as the
parent.
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32.
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If
D represents the dominant allele of a gene, then ____________________ represents the recessive
allele.
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33.
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A
chart used to predict results of genetic crosses is known as a(n) ____________________.
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34.
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In a
cross between two hybrid Tt pea plants, ____________________ percent of the offspring will be
Tt.
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Short Answer
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Use the diagram to answer each question.
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35.
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Identify structure A and state what it is made of.
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36.
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Identify structures B and C.
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37.
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Identify structure D and state where it is made.
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38.
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Identify structure E and describe its function.
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39.
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What
are the three nitrogen bases in transfer RNA that pair with bases A-G-U in messenger
RNA?
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40.
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If
one of the nitrogen bases on structure D were replaced by a different base, what effect might that
have on protein synthesis?
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