GENETICS & HEREDITY
In humans, the allele for dimples (D) is dominant. The allele for not having dimples (d) is recessive. A woman
(DD) and a man (Dd) have four children. Which of these is the predicted ratio of the children with dimples to
the children without dimples?
A.
B.
C.
D.
1:0
1:1
1:3
3:1
Correct Answer:
A
In humans, the allele for unattached (free) earlobes (F) is dominant. The allele for attached earlobes (f) is
recessive. A woman who is heterozygous for this trait marries a man who has attached earlobes. What is the
probability that this couple's child will have unattached earlobes?
A.
B.
C.
D.
25%
50%
75%
100%
Correct Answer:
B
The presence or absence of freckles is determined by one gene. The allele for freckles (F) is dominant and the
allele for the absence of freckles (f) is recessive.
A couple has several children. All of the children have freckles because their parents' genotypes can only
produce children with freckles.
Which of these are most likely the genotypes of the two parents?
A.
B.
C.
D.
Ff and ff
FF and ff
Ff and Ff
ff and ff
Correct Answer:
B
In horses, the allele for straight hair (B) is dominant to the allele for curly hair (b). Which of these sets of
parents can produce offspring with curly hair?
A.
B.
C.
D.
a heterozygous male with straight hair and a homozygous female with straight hair
a homozygous male with curly hair and a homozygous female with straight hair
a heterozygous male with straight hair and a heterozygous female with straight hair
a homozygous male with straight hair and a homozygous female with straight hair
Correct Answer:
C
Use the information and the table below to answer the following.
A group of students wanted to determine how the ability to taste PTC, a nontoxic chemical, is passed from one
generation to the next. The students decided to test families in their community for this ability. The students
gave each family member a paper strip coated with a small amount of PTC. Those who experienced the bitter
taste of PTC when they touched the paper strips to their tongues were called "tasters"; those who could not taste
the PTC were called "nontasters."
The results of the experiment are shown in the table below.
Which of these explains how two taster parents could produce a nontaster child?
A.
B.
C.
D.
Both parents are heterozygous and produce a homozygous recessive child.
Both parents are homozygous recessive and produce a homozygous dominant child.
Both parents are heterozygous and produce a heterozygous child.
Both parents are homozygous dominant and produce a homozygous recessive child.
Correct Answer:
A
In humans, the allele for long eyelashes is dominant (L) and the allele for short eyelashes is recessive (l). A
female who is heterozygous for long eyelashes and a male with short eyelashes have a child.
What is the probability that their offspring will have short eyelashes?
A.
B.
C.
D.
0%
25%
50%
75%
Correct Answer:
C
In a species of plant, the allele for red flowers (R) is dominant to the allele for orange flowers (r). Red flower
color in the plants is not sex-linked. Students crossed plants that had red flowers and recorded the flower color
of their offspring. Their data are shown below.
Plant Offspring
Flower Color Number of Offspring
Red
77
Orange
27
What are the most likely genotypes of the parent plants?
A.
B.
C.
D.
RR and rr
Rr and Rr
rr and rr
RR and Rr
Correct Answer:
B
One kind of chromosomal abnormality can occur during meiosis when a pair of chromosomes that carry genes
for the same trait fail to separate. Which of these represents the sex chromosomes of a male organism when this
type of chromosomal abnormality has occurred?
A.
B.
C.
D.
XXY
XX
XY
XXX
Correct Answer:
A
The allele for attached earlobes (f) is recessive to the allele for unattached (free) earlobes (F). A woman with the
genotype (Ff) and a man with the genotype (ff) have a child.
What is the probability that the child is heterozygous for attached earlobes?
A.
B.
C.
D.
0%
25%
50%
75%
Correct Answer:
C
Which of these is an example of a heterozygous genotype?
A.
B.
C.
D.
Rr
RR
wrinkled
round
Correct Answer:
A
Use the information and Punnett square below to answer the following question.
In guinea pigs, the allele for black fur (B) is dominant. The allele for brown fur (b) is recessive. Two guinea
pigs were crossed as shown in the Punnett square below. Numbers 1, 2, 3, and 4 represent the types of offspring
produced from the cross.
What is the probability that an offspring from this cross would have brown fur?
A.
B.
C.
D.
0%
25%
50%
75%
Correct Answer:
A
Use the information and Punnett square below to answer the following question.
In guinea pigs, the allele for black fur (B) is dominant. The allele for brown fur (b) is recessive. Two guinea
pigs were crossed as shown in the Punnett square below. Numbers 1, 2, 3, and 4 represent the types of offspring
produced from the cross.
Which of these describes the phenotypes of the parent guinea pigs?
A.
B.
C.
D.
Both parents have black fur.
Both parents have brown fur.
One parent has black fur, and the other has brown fur.
One parent has a mixture of black and brown fur, and the other has black fur.
Correct Answer:
A
One parent is homozygous dominant for brown hair (BB). The other parent is heterozygous for brown hair (Bb).
What is the probability that the offspring will have brown hair?
A.
B.
C.
D.
100%
75%
50%
25%
Correct Answer:
A
Red-green color blindness affects about 7.0% of the human male population. It affects approximately 0.4% of
the human female population. These data suggest that red-green color blindness is a
A.
B.
C.
D.
dominant trait carried on the Y chromosome
dominant trait carried on the X chromosome
recessive trait carried on the Y chromosome
recessive trait carried on the X chromosome
Correct Answer:
D
In humans the trait of having freckles (F) is dominant to not having freckles (f).
Which genotype and phenotype are correctly paired?
A.
B.
C.
D.
FF—no freckles
Ff—no freckles
Ff—freckles
ff—freckles
Correct Answer:
C
How many nucleotides are needed to code for one amino acid?
A.
B.
C.
D.
1
3
4
6
Correct Answer:
B
Which RNA sequence is produced using the DNA sequence AGC-TAC-ACT?
A.
B.
C.
D.
UCG-AUG-UGA
UCG-UAC-ACU
TCG-ATG-TGA
AGC-UAC-ACU
Correct Answer:
A
Hemoglobin is an important protein in red blood cells. The DNA code for hemoglobin contains the following
segment:
TGC-GGA-CTC-CTC
Which of these is the messenger RNA code for this segment of DNA?
A.
B.
C.
D.
ACG-CCT-GAA-GAA
TCC-GGT-CTC-CTC
ACG-CCU-GAG-GAG
UGC-GGA-CUC-CUC
Correct Answer:
C
The diagram below shows the key steps for making proteins. (Use to answer the following TWO questions)
Which step involves transfer RNA?
A.
B.
C.
D.
I
II
III
IV
Correct Answer:
D
According to the diagram, in which step is messenger RNA being constructed?
A.
B.
C.
D.
I
II
III
IV
Correct Answer:
B
Look at the DNA sequence below.
GAA
TTC
GCA
What do the G and A represent in the DNA sequence?
A.
B.
C.
D.
sugars
amino acids
phosphates
nitrogen bases
Correct Answer:
D
Scientists have recently discovered a new species that lives attached to the side of a tree. An organism from this
new species





is multicellular
has cell walls
has vascular tissues
makes its own food
has structures that absorb moisture from the air
The scientists learned that this organism produces a special protein that prevents it from freezing in cold
weather. Which of these contains the information for making this protein?
A.
B.
C.
D.
a vacuole
a lipid
a vitamin
a gene
Correct Answer:
D
Which of the following is correctly matched with its function?
A.
B.
C.
D.
rRNA - contains codes to make new ribosomes
DNA - carries the amino acids to the ribosomes
tRNA - combines with proteins to make up ribosomes
mRNA - carries genetic codes from nucleus to the ribosomes
Correct Answer:
D
Which of these statements best explains how genes and proteins are related?
A.
B.
C.
D.
Genes are segments of DNA that code for proteins.
Proteins are segments of DNA that code for genes.
Genes are the building blocks of proteins.
Proteins are the building blocks of genes.
Correct Answer:
A
A strand of DNA has a nucleotide base sequence of TAC-CGG-AGT. Which of the following is the
complementary mRNA nucleotide sequence produced from the strand of DNA?
A.
B.
C.
D.
UAC-CGG-AGU
ACU-GAA-CGA
AGU-UCC-UAC
AUG-GCC-UCA
Correct Answer:
D
A cellular process uses a strand of genetic material to produce a new strand. Parts of the strands are shown
below.
Original strand ATT CAG
New strand
UAA GUC
This new strand will most likely be used for
A.
B.
C.
D.
gene splicing
DNA synthesis
crossing-over
protein synthesis
Correct Answer:
D
The genetic information for making a protein must move from the nucleus to the cytoplasm. Which of these
moves this information to the cytoplasm?
A.
B.
C.
D.
a ribosome
DNA
RNA
an amino acid
Correct Answer:
C
What is one role of transfer RNA in the cell?
A.
B.
C.
D.
preparing the genes for messenger RNA
changing nitrogen bases into amino acids
preparing messenger RNA for the ribosomes
carrying amino acids to the ribosomes
Correct Answer:
D
The nucleotide base sequence of a strand of DNA is TAC-CGG-AGT. What is the sequence of the
complementary DNA strand?
A.
B.
C.
D.
TAC-CGG-AGT
ACT-GAA-CGA
AGT-TCC-TAC
ATG-GCC-TCA
Correct Answer:
D
Which of these make up the primary link between a gene and the expression of a trait?
A.
B.
C.
D.
proteins
sugars
lipids
vitamins
Correct Answer:
A
Which of these best describes the correct sequence in the expression of a trait?
A.
B.
C.
D.
trait → gene → enzyme
gene → protein → trait
protein → gene → trait
gene → trait → DNA
Correct Answer:
B
Use the information below to answer the following item.
Scientists genetically modified a variety of corn to protect it against pests like the corn borer. The corn borer is
an insect caterpillar that feeds on the corn stalk, which weakens the stalk and makes it fall over. A new gene in
the genetically modified corn causes the plant to produce a chemical that is toxic to the corn borer. Some people
are concerned that the genetically modified corn could harm other insects such as the monarch butterfly
caterpillar. The monarch caterpillar eats leaves of milkweed plants that might be coated with toxic corn pollen.
However, not all researchers agree with the concerns regarding the monarch butterfly caterpillar. They state that
it is unusual for large amounts of harmful corn pollen to be found on milkweed leaves. Also, only a small
percentage of caterpillars feed on the milkweed plants near corn fields.
Which was most likely introduced into corn that made it pest-resistant?
A.
B.
C.
D.
gene
lipid
toxin
protein
Correct Answer:
A
Use the technical passage and drawing to answer the following TWO items
BOGTURTLES
One of the smallest turtles in the world is found along the east coast of
the United States from Massachusetts to Georgia. The bog turtle,
measuring only 100 millimeters in length, was unknown in Maryland
before 1941. A drawing of a bog turtle is shown below.
Studies conducted in recent decades verified that Maryland was
included in the range of the bog turtle. It was often misidentified
because the colorful orange patterns on its head and neck resembled
other turtles. To learn more about the bog turtle, scientists conducted a
survey of its habitat sites. The results of the survey led to a more
thorough investigation of bog turtle sites by the Maryland Department
of Natural Resources. As a result, the number of sites increased from
one verified site in 1944 to 177 verified sites in 1984.
Known bog turtle sites are less than one acre in size. Bog turtles prefer to live in areas of low-lying wetlands, swamps, and
meadows that are soft and muddy. These habitats aid in body temperature regulation and egg incubation. Ground water
springs provide an area where the turtles can spend winter without the threat of freezing. The vegetation in the bog turtle
habitat consists of cattails, sphagnum moss, and various native grasses. Although the bog turtle population may never
have been large, habitats since precolonial times have declined because of development and changing farm practices.
The state of Maryland added the bog turtle to the list of endangered species in 1972. Steps to protect its habitat include
land use management, bog preservation, private landowner cooperation, management of invasive plant species, as well as
captive breeding programs. By adding federal protection to the existing protection provided at the state level, one of the
smallest turtles in the world may continue to survive.
Which of these is responsible for the color patterns on the head and neck of the bog turtle?
A.
B.
C.
D.
carbohydrates
diet
habitat
proteins
Correct Answer:
D
Which of these processes would most likely cause new color patterns on the head and neck of bog turtles?
A.
B.
C.
D.
mitosis
mutation
succession
replication
Correct Answer:
B
An Olympic gold medalist in cross-country skiing has a gene which causes him to produce 50% more
hemoglobin than the average person. Which of these most likely caused this trait?
A.
B.
C.
D.
a special diet designed for the skier
the climate where the skier lives
the training routine of the skier
a mutation carried by the skier
Correct Answer:
D
Which of these results when one nitrogen base replaces another in a segment of genetic material?
A.
B.
C.
D.
an enzyme substrate
a mutation
a feedback loop
an adaptation
Correct Answer:
B
A rare disorder is caused by changes in a gene. Parents of individuals with the disorder have only normal copies
of this gene. Which of these most likely causes this disorder?
A.
B.
C.
D.
mitosis
gene splicing
mutation
natural selection
Correct Answer:
C
Use the information below to answer the following item.
A pair of laboratory mice are crossed to obtain offspring. Three alleles found in the female gamete are ABC.
Three alleles found in the male gamete are Abc.
What is formed when a male gamete combines with a female gamete?
A.
B.
C.
D.
zygote
egg
sperm
chromosome
Correct Answer:
A
A scientist cloned a goat. Which of these is a true statement about the cloned goat?
A.
B.
C.
D.
It has new genes and traits.
It lacks the genes for reproduction.
It has genes that are identical to the original goat.
It looks the same as the original goat but has different genes.
Correct Answer:
Two segments of DNA are shown in the diagram below.
Normal thymine (T) is found in the old strand. It is replaced by an abnormal molecule (T*) in the new strand.
The abnormal molecule (T*) binds to guanine (G) instead of binding to adenine (A). This is an example of
A.
B.
C.
D.
an adaptation
protein synthesis
a mutation
binary fission
Correct Answer:
C
A scientist is trying to discover a new treatment to stop cancer cells from dividing. In the cancer cells, which of
these processes will stop if the treatment is successful?
A.
B.
C.
D.
mitosis
chemosynthesis
binary fission
genetic recombination
Correct Answer:
A
Use the diagram of the two different organisms and the information below to answer the following.
Streptococcus is a type of bacteria that causes strep throat in humans. A frog is a multicellular organism that
lives in aquatic environments.
Which of these is the type of reproduction used by Streptococcus?
A.
B.
C.
D.
binary fission
meiosis
crossing-over
budding
Correct Answer:
A
A protein called p53 can keep cells from dividing. To prevent cell division, this protein most likely stops
A.
B.
C.
D.
osmosis
mitosis
respiration
mutation
Correct Answer:
B
Cholera bacteria live inside copepods, tiny marine organisms. This type of microscopic bacteria harms the
copepods by feeding off their internal tissues.
Both of these organisms are found in oceans throughout the world. Unfavorable temperatures or salt levels may
cause cholera bacteria to become inactive. When inactive, they do not feed or reproduce. When conditions
become favorable, they become active once again.
A cholera population may depend on the population of copepods in the surrounding water. A simple food chain
showing this relationship is shown below.
Cholera bacteria perform binary fission to
A.
B.
C.
D.
reproduce asexually
digest food rapidly
regulate temperature
increase body size
Correct Answer:
A
A stuudent observ
ves a unicellu
ular organism
m under a microscope.
m
A
After a whilee, the organiism begins too split into
two cells, as shown in the diagram.
b describees the processs shown in the
t diagram??
Whicch of these best
A
A.
B
B.
C
C.
D
D.
binary fisssion
meiosis
osmosis
sexual reeproduction
Corrrect Answerr:
A
Use the informattion and the diagram bellow to answeer the follow
wing item.
a amoeba, a unicellularr organism.
The diagram bellow shows sttages of cell division of an
w does the ch
hromosome number
n
of th
he amoeba in
n stage 1 com
mpare to an amoeba in sstage 3?
How
A
A.
B
B.
C
C.
D
D.
half the number
n
of ch
hromosomess
the same number of chromosome
c
es
twice thee number of chromosomees
four timees the numbeer of chromo
osomes
Corrrect Answerr:
B
Use the informattion and the diagram bellow to answeer the follow
wing item.
The diagram bellow shows sttages of cell division of an
a amoeba, a unicellularr organism.
f
that th
he rate of div
vision in amo
oebas is conttrolled. Scienntists believve that the traansition from
m
Scienntists have found
stagee 2 to stage 3 is slowed by
b proteins. The addition
nal time seem
ms to help thhe amoeba cchange codinng errors
caused during DNA replicatiion.
Speccialized proteeins control cell division
n in the amoeeba. Which cell part is rresponsible ffor making thhese
proteeins?
A
A.
B
B.
C
C.
D
D.
mitochon
ndrion
nucleus
pseudopo
od
ribosomee
Corrrect Answerr:
D
After an egg celll containing 16 chromosomes is fertiilized, how m
many chrom
mosomes willl be present in the
zygoote?
A
A.
B
B.
C
C.
D
D.
8
16
32
64
Corrrect Answerr:
C
Use the information below to answer the following item.
Scientists determined that excess fertilizer from farms entered a shallow lake. The fertilizer caused an increase
in aquatic plants in the lake and then a decrease in oxygen in the water. Next, organic debris collected on the
bottom of the lake. Over several years, the lake gradually filled in with organic sediment.
One species of aquatic plant found in the lake has 84 chromosomes in each cell. As nutrient levels increased,
the population of this species increased through vegetative reproduction (also known as runners). How many
chromosomes were in the cells of the offspring?
1.
2.
3.
4.
21
42
84
168
Correct Answer:
C
Use the information below to answer the following.
The largest flower in the world, called a rafflesia, is three feet wide and weighs up to 36 pounds. The rafflesia
has no roots, stems, or leaves. It lives on and takes nourishment from a vine called tetrastigma. The rafflesia
harms the vine.
The seeds of the rafflesia are dispersed in an unusual way. Plantain squirrels and tree shrews eat parts of the
rafflesia plant. Scientists observe that when the animals chew the rafflesia, seeds get caught in their teeth. The
animals will then chew on tetrastigma vines, leaving the seeds where they can germinate.
Specialized cells in the rafflesia flowers undergo a process that produces gametes. What is this process called?
A.
B.
C.
D.
binary fission
meiosis
fertilization
enzyme regulation
Correct Answer:
B
Which of these represents the number of chromosomes in cells before and after the process of meiosis?
A.
B.
C.
D.
n n
n 2n
2n n
2n 2n
Correct Answer:
C
Which of these describes a mutation that can be inherited?
A.
B.
C.
D.
random breakage in a liver cell's DNA
abnormal lung cells produced by toxins in smoke
a nitrogen base substitution in a gamete cell
ultraviolet radiation damage to skin cells
Correct Answer:
C
A sperm cell of a moth has 112 chromosomes. How many chromosomes are in the moth's wing cells?
A.
B.
C.
D.
66
112
224
448
Correct Answer:
C
Reproductive cells are produced during
A.
B.
C.
D.
mitosis
meiosis
fertilization
budding
Correct Answer:
B
Which of these is produced as a result of fertilization?
A.
B.
C.
D.
a zygote with twice the number of chromosomes as a gamete
an egg with half the number of chromosomes as a zygote
a gamete with twice the number of chromosomes as a zygote
a zygote with half the number of chromosomes as a gamete
Correct Answer:
A
Corals are marine animals that often live in tropical seas. Many types of corals have unicellular algae living in
their tissues. The algae provide up to 98 percent of the corals' food. The corals provide protection and inorganic
nutrients for the algae.
Some coral cells undergo meiosis. Which of these would not occur during meiosis?
A.
B.
C.
D.
formation of a zygote
chromosomes crossing-over
production of gametes
reduction in number of chromosomes
Correct Answer:
A
Which of these does not occur during meiosis?
A.
B.
C.
D.
production of identical gametes
production of new gene combinations
crossing-over of homologous chromosomes
reduction of chromosome number by one-half
Correct Answer:
A
Horses have 64 chromosomes in each body cell. If a horse cell undergoes meiosis, how many chromosomes
should be in each gamete?
A.
B.
C.
D.
16
32
64
128
Correct Answer:
B
What process produces male and female reproductive cells in plants?
A.
B.
C.
D.
mitosis
meiosis
replication
fertilization
Correct Answer:
B
Which of these combinations results in the expression of a recessive trait?
A.
B.
C.
D.
two dominant alleles
a dominant sex-linked allele and a Y chromosome
two recessive alleles
a dominant allele and a recessive allele
Correct Answer:
C