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
hybrid is the offspring of parents that have different alleles for a trait.
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3.
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A pea
plant that is heterozygous for tall stems has the alleles Tt.
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4.
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A
Punnett square shows all the possible combinations of alleles in parents.
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5.
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An
organism’s physical appearance is its phenotype.
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6.
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The
sex cells produced by meiosis have twice the number of chromosomes as the parent
cells.
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7.
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Chromosomes carry genes from parents to offspring.
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8.
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The
number of DNA bases forms a genetic code.
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9.
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Transfer RNA carries coded messages from the nucleus to the
cytoplasm.
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10.
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A
mutation in a sex cell can be passed to offspring.
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11.
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Even
if a gene has multiple alleles, a person cannot have more than three of those
alleles.
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12.
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Trait
such as height and skin color that have many different phenotypes are often controlled by a single
gene.
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13.
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A
person’s environment can affect his or her genotype for certain traits, such as
height.
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14.
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Sex-linked traits that are controlled by recessive alleles are more likely to
show up in males.
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15.
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A
male is represented by a square in a pedigree.
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16.
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A
genetic disorder in which an abnormal form of hemoglobin is produced is
hemophilia.
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17.
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A
doctor can look at the chromosomes of a cell in a karyotype.
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18.
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The
technique called cloning produces an organism that is genetically identical to its
parent.
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19.
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Except for identical twins, all people have the same DNA.
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20.
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The
goal of DNA fingerprinting is to prepare an encyclopedia that shows the DNA sequence of every
gene.
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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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21.
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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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22.
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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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23.
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Factors that control traits are called a. | genes. | b. | purebreds. | c. | recessives. | d. | parents. | | |
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24.
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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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25.
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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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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 recessive allele | d. | one dominant
allele and one recessive allelle | | |
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27.
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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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28.
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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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29.
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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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30.
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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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31.
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An
organism’s physical appearance is its a. | genotype. | b. | phenotype. | c. | codominance. | d. | heterozygous. | | |
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32.
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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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33.
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What
is the chromosome theory of inheritance? a. | Chromosomes are carried from parents to offspring on
hybrids. | b. | Genes are carried from parents to offspring on
chromosomes. | c. | Hybrid pairs of chromosomes combine to form
offspring. | d. | Codominant genes combine to form new
hybrids. | | |
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34.
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Walter Sutton discovered that the sex cells of grasshoppers have
exactly a. | 12 times the
number of chromosomes found in the body cells. | b. | twice the number
of chromosomes found in the body cells. | c. | the same number of chromosomes found in the body
cells. | d. | half the number of chromosomes found in the body
cells. | | |
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35.
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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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36.
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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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37.
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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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38.
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The
order of the bases along a gene determines the order in which a. | sugars are put
together to form a carbohydrate. | b. | genes are arranged on a chromosome. | c. | amino acids are
put together to form a protein. | d. | chromosomes are arranged in the
nucleus. | | |
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39.
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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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40.
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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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41.
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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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42.
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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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43.
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Which
term refers to physical characteristics that are studied in genetics? a. | traits | b. | offspring | c. | generations | d. | hybrids | | |
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44.
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The
different forms of a gene are called a. | alleles. | b. | factors. | c. | masks. | d. | traits. | | |
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45.
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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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46.
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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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47.
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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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48.
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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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49.
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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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50.
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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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51.
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Which
of these traits is controlled by a gene with multiple alleles? a. | straight
hairline | b. | smile dimples | c. | widow’s
peak | d. | blood
type | | |
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52.
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What
are multiple alleles? a. | more than two genes that control a
trait | b. | three or more forms of a gene that code for a single
trait | c. | three or more chromosomes that determine a
trait | d. | more than two codominant genes in a
chromosome | | |
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53.
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Why
does height in humans have such a wide variety of phenotypes? a. | Height is
controlled by at least four genes. | b. | The gene for height has only two
alleles. | c. | Height is controlled by sex-linked
genes. | d. | Height is controlled by a recessive
allele. | | |
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54.
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What
controls variations in skin color among humans? a. | a person’s diet | b. | at least three
genes | c. | multiple alleles of a single gene | d. | two alleles of a
single gene | | |
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55.
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Which
of these human traits is altered by variations in environment? a. | hairline | b. | height | c. | smile
dimples | d. | blood type | | |
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56.
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What
factors can affect a person’s height? a. | genes only | b. | environmental
factors only | c. | both genes and environmental factors | d. | the sex
chromosomes a person inherits | | |
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57.
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Which
combination of sex chromosomes results in a male human being? a. | XX | b. | YY | c. | XY | d. | either XX or YY | | |
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58.
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Why
are sex-linked traits more common in males than in females? a. | All alleles on
the X chromosome are dominant. | b. | All alleles on the Y chromosome are
recessive. | c. | A recessive allele on the X chromosome will always produce the
trait in a male. | d. | Any allele on the Y chromosome will be codominant with the
matching allele on the X chromosome. | | |
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59.
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How
does a geneticist use pedigrees? a. | to create genetic crosses | b. | to replicate
identical strings of DNA | c. | to prove that sex-linked traits are caused by codominant
alleles | d. | to trace the inheritance of traits over generations of
families | | |
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60.
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What
is a pedigree? a. | a chart that
tracks which members of a family have a particular trait | b. | a geneticist who
studies the inheritance of traits in humans | c. | a picture of all
of the chromosomes in a cell | d. | an allele passed from parent to child on a sex
chromosome | | |
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61.
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Genetic disorders are caused by a. | pedigrees. | b. | mutations. | c. | dominant alleles. | d. | sickle-shaped
cells. | | |
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62.
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Which
genetic disorder causes the body to produce unusually thick mucus in the lungs and
intestines? a. | hemophilia | b. | Down syndrome | c. | cystic
fibrosis | d. | sickle-cell disease | | |
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63.
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What
is a karyotype? a. | blood from a
newborn baby | b. | a picture of a baby before it is born | c. | a picture of the
chromosomes in a cell | d. | fluid that surrounds a baby before it is
born | | |
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64.
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How
can genetic counselors predict genetic disorders? a. | by studying karyotypes and pedigree
charts | b. | by taking pictures of a baby before it is
born | c. | by exploring new
methods of genetic engineering | d. | by eliminating codominant alleles in the
parents | | |
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65.
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Cloning results in two organisms that are a. | both adult
mammals. | b. | produced from cuttings. | c. | genetically
similar. | d. | genetically identical. | | |
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66.
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Which
of these is an example of the benefits of genetic engineering? a. | cross-breeding
to create disease-resistant crops | b. | creating human insulin to treat people with
diabetes | c. | analyzing karyotypes and pedigree
charts | d. | growing a new plant from a cutting | | |
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67.
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No
two people have the same DNA, except for a. | crime suspects. | b. | brothers. | c. | sisters. | d. | identical
twins. | | |
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68.
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How
do police use DNA fingerprinting to help solve crimes? a. | by proving that
a suspect’s blood type matches evidence in a crime | b. | by showing that
a suspect’s fingerprints are at a crime scene | c. | by comparing a
suspect’s DNA patterns with evidence from a crime scene | d. | by matching
phenotypes of suspects with DNA samples | | |
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69.
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What
is the purpose of the Human Genome Project? a. | to identify the DNA sequence of every gene in the human
genome | b. | to clone every gene on a single chromosome in human
DNA | c. | to splice every
gene on a single chromosome in human DNA | d. | to inbreed the best genes on every chromosome in human
DNA | | |
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70.
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What
is a genome? a. | all the cells
produced during meiosis | b. | all the plasmids from splicing DNA in a
cell | c. | all the DNA in
one cell of an organism | d. | all the karyotypes in a cell | | |
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71.
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One
parent of a child has type A blood and the other has type B blood. What is the child’s blood
type? a. | Type
A | b. | Type
B | c. | Type
AB | d. | Type
O | | |
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72.
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Sex-linked genes are genes on a. | the X chromosome only. | b. | the Y chromosome
only. | c. | the X and Y chromosomes. | d. | all 23 pairs of
chromosomes. | | |
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73.
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Which
form of selective breeding crosses genetically different individuals in an attempt to keep the best
traits of both parents? a. | genetic engineering | b. | inbreeding | c. | hybridization | d. | cloning | | |
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74.
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Which
form of selective breeding crosses parents with the same or similar sets of alleles? a. | fertilization | b. | inbreeding | c. | hybridization | d. | cloning | | |
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75.
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A
carrier is a person who has a. | one recessive and one dominant allele for a
trait. | b. | two recessive alleles for a trait. | c. | two dominant
alleles for a trait. | d. | more than two alleles for a trait. | | |
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76.
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What
must occur for a girl to be colorblind? a. | Each parent must be colorblind. | b. | Each parent must
have the dominant allele for colorblindness. | c. | Each parent must
have the recessive allele for colorblindness. | d. | Each parent must
have two codominant alleles for colorblindness. | | |
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77.
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Hemophilia is caused by a(n) a. | recessive allele on the X chromosome. | b. | extra
chromosome. | c. | dominant allele. | d. | codominant
allele. | | |
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78.
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Down
syndrome most often occurs when a. | a person inherits a recessive allele. | b. | chromosomes fail
to separate properly during meiosis. | c. | sickle-shaped cells become stuck in blood
vessels. | d. | blood fails to clot properly. | | |
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79.
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What
genetic disorder results in abnormally shaped blood cells? a. | hemophilia | b. | Down syndrome | c. | cystic
fibrosis | d. | sickle-cell disease | | |
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80.
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What
procedure helps doctors diagnose a genetic disorder before a baby is born? a. | genetic
engineering | b. | selective breeding | c. | amniocentesis | d. | cloning | | |
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Short Answer
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Use the diagram to answer each question.
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81.
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In
which generation are the parents purebred? In which generation are they hybrids?
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Use the diagram to answer each question.
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82.
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Could
the trait that is traced by this pedigree be sex-linked? Explain why or why not.
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Use the diagram to answer each question.
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83.
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Identify structures A and B. What do these structures contain?
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84.
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Explain what is happening in Step 4.
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