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WorksheetsAP Biology Unit 5: Heredity REVIEW
Total questions: 90
Worksheet time: 8hrs 30mins
What is a genome?
The complete complement of an organismʹs genes
A specific set of polypeptides within each cell
Which of the following statements about genes is incorrect?
Genes correspond to segments of DNA.
Many genes contain the information needed for cells to synthesize enzymes and other proteins.
During fertilization, both the sperm and the ovum contribute genes to the resulting fertilized egg.
One gene only is used in a specific cell type.
Asexual reproduction and sexual reproduction differ in all but which of the following ways?
Individuals reproducing asexually transmit 100% of their genes to their progeny, whereas individuals reproducing sexually transmit only 50%.
Asexual reproduction is utilized only by fungi and protists, whereas sexual reproduction is utilized only by plants and animals.
If a horticulturist breeding gardenias succeeds in having a single plant with a particularly desirable set of traits, which of the following would be her most probable and efficient route to establishing a line of such plants?
Backtrack through her previous experiments to obtain another plant with the same traits.
Clone the plant asexually to produce an identical one
Breed this plant with another plant with much weaker traits
Asexual reproduction results in identical offspring unless which of the following occurs?
Natural selection
Mutation
Crossing over
A geneʹs location along a chromosome is known as which of the following?
Allele
Sequence
Locus
What is a karyotype?
The combination of chromosomes found in a gamete
A display of every pair of homologous chromosomes within a cell, organized according to size and shape
At which stage of mitosis are chromosomes usually photographed in the preparation of a karyotype?
prophase
metaphase
The human X and Y chromosomes
are both present in every somatic cell of males and females alike.
include genes that determine an individualʹs sex.
include only genes that govern sex determination.
Which of the following is true of a species that has a chromosome number of 2n = 16?
The species is diploid with 32 chromosomes per cell.
Each cell has 8 homologous pairs.
Which of these statements is false?
In humans, each of the 22 maternal autosomes has a homologous paternal chromosome
In humans, the 23rd pair, the sex chromosomes, determines whether the person is female (XX) or male (XY).
Single, haploid (n) sets of chromosomes in ovum and sperm unite during fertilization, forming a diploid (2n), single-celled zygote.
At sexual maturity, ovaries and testes produce diploid gametes by meiosis.
In animals, meiosis results in gametes, and fertilization results in
spores
gametophytes
zygotes
clones
Which of the following is an example of alternation of generations?
A diploid plant (sporophyte) produces, by meiosis, a spore that gives rise to a multicellular, haploid pollen grain (gametophyte).
A diploid animal produces gametes by meiosis, and the gametes undergo fertilization to produce a diploid zygote.
The karyotype of one species of primate has 48 chromosomes. In a particular female, cell division goes awry and she produces one of her eggs with an extra chromosome (25). The most probable source of this error would be a mistake in which of the following?
Telophase II of one meiotic event
Either anaphase I or II
A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following?
It must be a primate
Its gametes must have 23 chromosomes.
It must be sexually reproducing.
A triploid cell contains three sets of chromosomes. If a cell of a usually diploid species with 42 chromosomes per cell is triploid, this cell would be expected to have which of the following?
63 chromosomes in 21 sets of 3
63 chromosomes, each with three chromatids
After telophase I of meiosis, the chromosomal makeup of each daughter cell is
haploid, and the chromosomes are each composed of a single chromatid.
haploid, and the chromosomes are each composed of two chromatids.
Tetrads of chromosomes are aligned at the equator of the spindle; alignment determines independent assortment.
Prophase
Metaphase I
Prophase II
Anaphase II
Synapsis of homologous pairs occurs; crossing over may occur.
Prophase
Metaphase I
Anaphase I
Telophase I
Centromeres of sister chromatids disjoin and chromatids separate.
Anaphase II
Prophase I
Prophase II
Metaphase II
Which of the following happens at the conclusion of meiosis I?
Homologous chromosomes are separated.
Sister chromatids are separated.
A cell divides to produce two daughter cells that are genetically different.
The statement is true for mitosis only.
The statement is true for meiosis I only.
The statement is true for mitosis and meiosis I.
Homologous chromosomes synapse and crossing over occurs.
The statement is true for mitosis only.
The statement is true for meiosis I only.
The statement is true for meiosis II only.
Chromatids are separated from each other.
The statement is true for mitosis only.
The statement is true for meiosis I only.
The statement is true for meiosis II only.
The statement is true for mitosis and meiosis II.
Independent assortment of chromosomes occurs.
The statement is true for mitosis only.
The statement is true for meiosis I only.
You have isolated DNA from three different cell types of an organism, determined the relative DNA content for each type, and plotted the results on the graph shown in the figure. If the cells were from a plant, which sample might represent a gametophyte cell?
I
II
III
Which sample of DNA might be from a nerve cell arrested in G0 of the cell cycle?
I
II
III
Which sample might represent an animal cell in G2 phase of the cell cycle?
I
II
III
Which of the following occurs in meiosis but not in mitosis?
Chromosome replication
Synapsis of chromosomes
A tetrad includes which of the following sets of DNA strands?
Two single-stranded chromosomes that have synapsed
Two sets of sister chromatids that have synapsed
If a female of this species has one chromosome 12 with a blue gene and another chromosome 12 with an orange gene, she will produce which of the following egg types?
Only orange gene eggs
1/2 blue and 1/2 orange gene eggs
How does the sexual life cycle increase the genetic variation in a species?
By allowing independent assortment of chromosomes
By increasing gene stability
By decreasing mutation frequency
Independent assortment of chromosomes is a result of
the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I.
the random nature of the fertilization of ova by sperm.
When pairs of homologous chromosomes separate during anaphase I
the maternal chromosomes all move to the same daughter cell.
the sister chromatids remain attached to one another
Natural selection and recombination due to crossing over during meiosis I are related in which of the following ways?
Recombinants are usually selected against.
Recombinants may have combinations of traits that are favored by natural selection.
Recombination does not affect natural selection.
Pea plants were particularly well suited for use in Mendelʹs breeding experiments for all of the following reasons except that
peas show easily observed variations in a number of characters, such as pea shape and flower color.
it is possible to control matings between different pea plants.
it is possible to obtain large numbers of progeny from any given cross.
peas have an unusually long generation time.
What is the difference between a monohybrid cross and a dihybrid cross?
A dihybrid cross involves organisms that are heterozygous for two characters and a monohybrid only one.
A monohybrid cross is performed for one generation, whereas a dihybrid cross is performed for two generations.
A cross between homozygous purple-flowered and homozygous white-flowered pea plants results in offspring with purple flowers. This demonstrates
the blending model of genetics.
dominance.
true-breeding
The F1 offspring of Mendelʹs classic pea cross always looked like one of the two parental varieties because
one phenotype was completely dominant over another.
each allele affected phenotypic expression.
the traits blended together during fertilization.
What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants?
There is considerable genetic variation in garden peas.
Traits are inherited in discrete units, and are not the results of ʺblending.ʺ
Recessive genes occur more frequently in the F1 than do dominant ones.
Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. This suggests
that the parents were true-breeding for contrasting traits.
incomplete dominance
that the parents were both heterozygous
Two characters that appear in a 9:3:3:1 ratio in the F 2 generation should have which of the following properties?
Each of the traits is controlled by single genes.
The genes controlling the characters obey the law of independent assortment.
A sexually reproducing animal has two unlinked genes, one for head shape ( H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism?
HT
Hh
HhTt
T
It was important that Mendel examined not just the F1 generation in his breeding experiments, but the F2 generation as well, because
he obtained very few F1 progeny, making statistical analysis difficult.
parental traits that were not observed in the F1 reappeared in the F2.
When crossing an organism that is homozygous recessive for a single trait with a heterozygote, what is the chance of producing an offspring with the homozygous recessive phenotype?
0%
25%
50%
75%
Mendel accounted for the observation that traits which had disappeared in the F1 generation reappeared in the F2 generation by proposing that
the mechanism controlling the appearance of traits was different between the F1 and the F2 plants.
traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F1.
Which of the following about the law of segregation is false?
It is a method that can be used to determine the number of chromosomes in a plant.
It can be used to predict the likelihood of transmission of certain genetic diseases within families.
It can account for the 3:1 ratio seen in the F2 generation of Mendelʹs crosses.
The fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment most probably indicates which of the following?
None of the traits obeyed the law of segregation.
The diploid number of chromosomes in the pea plants was 7.
All of the genes controlling the traits behaved as if they were on different chromosomes.
Mendel was able to draw his ideas of segregation and independent assortment because of the influence of which of the following?
His experiments with the breeding of plants such as peas
His reading and discussion of Darwinʹs Origin of Species
Mendelʹs observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division?
Prophase I of meiosis
Anaphase I of meiosis
Anaphase of mitosis
Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails
(t). What fraction of the progeny of the cross BbTt × BBtt will have black fur and long tails?
1/16
3/16
3/8
1/2
In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?
1/2
1/4
1/6
0
Two true-breeding stocks of pea plants are crossed. One parent has red, axial flowers and the other has white, terminal flowers; all F1 individuals have red, axial flowers. The genes for flower color and location assort independently. If 1,000 F2 offspring resulted from the cross, approximately how many of them would you expect to have red, terminal flowers?
65
190
250
565
In a cross AaBbCc × AaBbCc, what is the probability of producing the genotype AABBCC?
1/4
1/8
1/16
1/64
Skin color in a certain species of fish is inherited via a single gene with four different alleles.
How many different types of gametes would be possible in this system?
1
2
4
8
A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. Which of the following is a possible partial genotype for the son?
IBIB
IBIA
ii
IBi
A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. Which of the following is a possible genotype for the mother?
IAIA
IBIB
ii
IAi
Which of the following is an example of polygenic inheritance?
Pink flowers in snapdragons
The ABO blood groups in humans
Huntingtonʹs disease in humans
Skin pigmentation in humans
Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others pink flowers. This can be best explained by which of the following?
Environmental factors such as soil pH
The allele for blue hydrangea being completely dominant
A woman has six sons. The chance that her next child will be a daughter is
1
1/2
0
1/6
Huntingtonʹs disease is a dominant condition with late age of onset in humans. If one parent has the disease, what is the probability that his or her child will have the disease?
1
3/4
1/2
1/4
The following questions refer to the pedigree chart in the following pedigree for a family, some of whose members exhibit the dominant trait, dark hair. Affected individuals are indicated by an open square or circle. What is the genotype of individual II-5?
WW
Ww
ww
What is the likelihood that the progeny of IV-3 and IV-4 will have dark hair?
0%
25%
50%
75%
[select all that apply] People with sickle-cell trait
are heterozygous for the sickle-cell allele.
are usually healthy.
have increased resistance to malaria.
produce normal and abnormal hemoglobin.
The frequency of heterozygosity for the sickle cell anemia allele is unusually high, presumably because this reduces the frequency of malaria. Such a relationship is related to which of the following?
Mendelʹs law of independent assortment
Mendelʹs law of segregation
Darwinʹs explanation of natural selection
Cystic fibrosis (CF) is a Mendelian disorder in the human population that is inherited as a recessive. Two normal parents have two children with CF. The probability of their next child being normal for this characteristic is which of the following?
0
1/2
1/4
3/4
Phenylketonuria (PKU) is a recessive human disorder in which an individual cannot appropriately metabolize a particular amino acid. This amino acid is not otherwise produced by humans. Therefore the most efficient and effective treatment is which of the following?
Transfuse the patients with blood from unaffected donors.
Regulate the diet of the affected persons to severely limit the uptake of the amino acid.
Feed the patients the missing enzymes in a regular cycle, i.e., twice per week.
A pedigree analysis for a given disorderʹs occurrence in a family shows that, although both parents of an affected child are normal, each of the parents has had affected relatives with the same condition. The disorder is then which of the following?
recessive
dominant
a new mutation
When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?
The gene involved is on the X chromosome.
The gene involved is on the Y chromosome.
The gene involved is on an autosome.
A man with Klinefelter syndrome (47, XXY) is expected to have any of the following EXCEPT
lower sperm count.
possible breast enlargement.
increased testosterone.
long limbs
A woman is found to have 47 chromosomes, including 3 X chromosomes. Which of the following describes her expected phenotype?
Enlarged genital structures
Excessive emotional instability
Normal female
Sterile female
SRY is best described in which of the following ways?
A gene region present on the Y chromosome that triggers male development
An autosomal gene that is required for the expression of genes on the Y chromosome
In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?
Tortoiseshell females; tortoiseshell males
Tortoiseshell females; black males
Cinnabar eyes is a sex-linked recessive characteristic in fruit flies. If a female having cinnabar eyes is crossed with a wild-type male, what percentage of the F1 males will have cinnabar eyes?
75%
25%
50%
100%
In birds, sex is determined by a ZW chromosome scheme. Males are ZZ and females are ZW. A recessive lethal allele that causes death of the embryo is sometimes present on the Z chromosome in pigeons. What would be the sex ratio in the offspring of a cross between a male that is heterozygous for the lethal allele and a normal female?
2:1 male to female
1:2 male to female
1:1 male to female
A Barr body is normally found in the nucleus of which kind of human cell?
Unfertilized egg cells only
Sperm cells only
Somatic cells of a female only
Which of the following statements is true?
The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them.
The observed frequency of recombination of two genes that are far apart from each other has a maximum value of 100%.
New combinations of linked genes are due to which of the following?
Nondisjunction
Crossing over
Independent assortment
What does a frequency of recombination of 50% indicate?
The two genes are likely to be located on different chromosomes.
Independent assortment is hindered.
A 0.1% frequency of recombination is observed
in genes located very close to one another on the same chromosome.
in any two genes on different chromosomes.
Between which two genes would you expect the highest frequency of recombination?
A and W
W and E
E and G
A and G
What is the reason that linked genes are inherited together?
They are located close together on the same chromosome.
The number of genes in a cell is greater than the number of chromosomes.
What is the mechanism for the production of genetic recombinants?
Methylation of cytosine
Crossing over and independent assortment
Nondisjunction
The frequency of crossing over between any two linked genes will be which of the following?
Higher if they are recessive
Proportional to the distance between them
A cell that has 2n + 1 chromosomes is
trisomic.
monosomic.
Women with Turner syndrome have a genotype characterized as which of the following?
Mental retardation and short arms
A karyotype of 45, X
The frequency of Down syndrome in the human population is most closely correlated with which of the following?
Age of the mother
Exposure of pregnant women to environmental pollutants
In order for chromosomes to undergo inversion or translocation, which of the following is required?
Point mutation
Chromosome breakage and rejoining
The pedigree in the figure shows the transmission of a trait in a particular family. Based on this pattern of transmission, the trait is most likely
mitochondrial.
autosomal recessive.
Mitochondrial DNA is primarily involved in coding for proteins needed for electron transport. Therefore in which body systems would you expect most mitochondrial gene mutations to be exhibited?
The immune system and the blood
Nervous and muscular systems
