Deck 5: The Chromosomal Basis Of Mendelism

Question 1

All chromosomes except X and Y are known as:

A) Autosomes
B) Somosomes
C) Sex chromosomes
D) Somatosomes
E) Tetrasomes

Answer 1

A

Question 2

An organism's standard chromosome number (n)is known as the ________ number.

A) Haploid
B) Diploid
C) Aneuploid
D) Polyploid
E) Tetraploid

Answer 2

A

Question 3

A cell is stained and viewed under a microscope and no chromosomes are visible.Which point in the cell cycle is the cell currently in?

A) Interphase
B) Prophase
C) Metaphase
D) Anaphase
E) Telophase

Answer 3

A

Question 4

A diffuse network of thin and loosely coiled chromosomes is referred to as:

A) Chromosomes
B) Cylinders
C) Chromatin
D) Chromomeres
E) Centromeres

Question 5

X and Y chromosomes are known as:

A) Autosomes
B) Somosomes
C) Sex chromosomes
D) Non-sex chromosomes
E) Somatosomes

Question 6

Which of the following is required to unambiguously link a gene to a chromosome?

A) The gene must be defined by a mutant allele
B) The chromosome must be morphologically distinguishable
C) The pattern of gene transmission must reflect the chromosome's behavior during reproduction.
D) All of these
E) None of these

Question 7

Which organism that was the first to be used to relate the behavior of chromosomes during meiosis to Mendel's principles of Segregation and Independent Assortment?

A) Garden peas
B) Summer squash
C) Drosophila
D) Chickens
E) Sweetpeas

Question 8

Why is the Y chromosome able to pair with the X chromosome during meiosis?

A) The Y chromosome has the same centromere placement as the X chromosome
B) The Y chromosome is the same length as the X chromosome
C) The X and Y chromosomes share small gene segments that allow them to act like homologues during meiosis
D) None of these
E) All of these

Question 9

Which of the following is a possible offspring in a mating between grasshoppers?

A) XO male
B) XX female
C) XO female
D) XO male and XX female
E) XO male and XO female

Question 10

A (w+/ w+)red-eyed Drosophila female is crossed with a white-eyed male.Assuming the trait for eye color is sex-linked,what are the possible phenotypes of the progeny?

A) All red eyed individuals
B) Red and white eyed females and males
C) Only red eyed females and white eyed males
D) Both red and white eyed males and only white eyed females
E) None of these

Question 11

An organism that has only one copy of a gene is called a:

A) Heterozygote
B) Homozygote
C) Hemizygote
D) Zygote
E) None of these

Question 12

The haploid number for a cell in a specific organism is 12.What is the number of chromosomes in a somatic cell in this organism?

A) 12
B) 24
C) 36
D) 48
E) 96

Question 13

In some animal species,like the grasshopper,sex is determined by:

A) The presence of the Y chromosome
B) The number of X chromosomes in relation to the number of sets of autosomes
C) The absence of the Y chromosome
D) The shorter nature of the Y chromosome
E) None of these

Question 14

Lightly stained regions of chromatin and darkly stained regions of chromatin are respectively known as:

A) Heterochromatin and euchromatin
B) Euchromatin and heterochromatin
C) Haploid and diploid
D) Eukaryotic and prokaryotic
E) Chromosome and nucleus

Question 15

Which individual is credited with linking the gene for eye color in Drosophila to the X chromosome?

A) Thomas Hunt Morgan
B) Calvin Bridges
C) Gregor Mendel
D) Sutton and Boveri
E) None of these

Question 16

In a certain species,a somatic cell has 48 chromsomes.How many chromosomes are in a sex cell?

A) 12
B) 24
C) 96
D) 144
E) 200

Question 17

Which of the following discovered chromosomes in the second half of the nineteenth century?

A) Thomas Morgan
B) Calvin Bridges
C) W. Waldeyer
D) Gregor Mendel
E) Edmund Beecher Wilson

Question 18

Cells that contain two of each of the chromosomes in a set are known as:

A) Haploid
B) Diploid
C) Aneuploid
D) Polyploid
E) Monoploid

Question 19

In some animal species,like humans,sex is determined by:

A) The presence of the Y chromosome
B) The number of X chromosomes in relation to the number of sets of autosomes
C) The size of the Y chromosome
D) None of these
E) All of these

Question 20

A (w+/ w)red-eyed Drosophila female is crossed with a white-eyed male.Assuming the trait for eye color is sex-linked,what are the possible phenotypes of the progeny?

A) All red eyed individuals
B) Red and white eyed females and males
C) Red eyed females and white eyed males
D) Both red and white eyed males and only white eyed females
E) None of these

Question 21

In Drosophila,X? denotes a white eyed allele and X? denotes the red-eyed allele.An X?X?Y female is crossed with an X?Y male.What are the possible progeny genotypes?

A) X?X?X?, X?Y
B) X?X?X?, X?X?Y, X?Y, X?O
C) X?X?, X?Y, X?O
D) Y0, X?X?X?, X?X?Y, X
E) None of these

Question 22

An individual with two kinds of gametes (i.e.X bearing and Y bearing)is referred to as:

A) Homogametic
B) Heterogametic
C) Heterozygous
D) None of these
E) All of these

Question 23

In Drosophila the Y chromosome is not required for male sex determination.However,it is required for :

A) Male sterility
B) Male fertility
C) Female sterility
D) Female fertility
E) None of these

Question 24

In humans the Y chromosome carries _________ genes than the X chromosome.

A) Fewer
B) More
C) Similar
D) All of these
E) None of these

Question 25

A color blind male mates with woman who has normal vision.The woman has no history of colorblindness in her family.What percentage of their sons are expected to be colorblind?

A) 25%
B) 50%
C) 75%
D) 100%
E) 0%

Question 26

Down Syndrome occurs when there is an extra chromosome #21.Such individuals therefore have 47 chromosomes.Assume that a mating occurs between a female with Down Syndrome and a normal male.Assuming normal disjunction during meiosis,what percentage of offspring would be expected to have Down Syndrome?

A) 25%
B) 50%
C) 75%
D) 100%
E) 0%

Question 27

The sex-linked disease called testicular feminization,if transferred from mother to son,forms:

A) males (XY) that are phenotypically female and sterile.
B) females (XY) that are sterile.
C) males (XY) that are sterile.
D) females (XY) that are phenotypically male and are sterile.
E) fertile males (XY)

Question 28

In humans an individual who is genotyped as XO is a:

A) Male
B) Female
C) Hermaphrodite
D) None of these
E) All of these

Question 29

Which of Mendel's principles is based on the separation of homologous chromosomes during the anaphase of the first meiotic division?

A) Dominance/Recessiveness
B) Segregation
C) Independent Assortment
D) All of these
E) None of these

Question 30

In a human,what is the best explanation for being XX and phenotypically male?

A) One of the X's is incomplete resembling a chromosome.
B) A small piece of the Y-chromosome, containing the SRY region, is inserted on the X-chromosome.
C) Both the X's have a mutation deleting the "female" forming genes.
D) There is a fragment of the Y-chromosome inserted on an autosomal chromosome.
E) The SRY gene has mutated.

Question 31

When chromosomes fail to separate during meiosis,thereby producing an egg with two X chromosomes or an egg with no X chromosome at all,this event is referred to as:

A) Nondisjunction
B) Disjunction
C) Polyploidy
D) Polysomy
E) None of these

Question 32

A(n)________________ gene has a locus on both the X-and Y-chromosome

A) Autosomal
B) Psedoautosomal
C) X-linked
D) Y-linked
E) None of these

Question 33

Which of Mendel's principles is a statement about the random alignment of different pairs of chromosomes at metaphase during meiosis?

A) Dominance/Recessiveness
B) Segregation
C) Independent Assortment
D) All of these
E) None of these

Question 34

A Drosophila is determined to have the genotype XO.What can you determine about this individual based upon this information?

A) The individual is mae
B) The individual is sterile
C) The individual is male and sterile
D) The individual is female and sterile

Question 35

Which of the following is an X-linked disorder in human beings?

A) Hemophilia
B) Color blindness
C) HIV
D) Hemophiila and Color blindness
E) All of these

Question 36

The view that all genes are located on chromosomes and that Mendel's principles can be explained by the transmissional properties of chromosomes during reproduction is known as:

A) The Cell Theory
B) The Chromosome Theory of Heredity
C) The Sex-Linked Inheritance Theory
D) All of these
E) None of these

Question 37

Sexual dimorphism can be determined by:

A) The environment
B) Temperature
C) Genetic factors
D) All of these
E) None of these

Question 38

A white eyed Drosophila female is crossed with a red-eyed male.Assuming the trait for eye color is sex-linked,what are the possible phenotypes of the progeny?

A) All red eyed individuals
B) Red and white eyed females and males
C) Red eyed females and white eyed males
D) Red and white eyed males and only white eyed females
E) None of these

Question 39

Which of the following is the part of the Y chromosome that is critical for normal male development?

A) SRY
B) Pseudoautosomal region
C) Centromere
D) All of these
E) None of these

Question 40

Why is it easier to identify a recessive sex-linked trait in human beings than a recessive autosomal trait?

A) A male needs only to inherit one recessive allele to express an X-linked trait
B) A male needs to inherit two recessive alleles to express an X-linked trait
C) A female only needs to inherit one recessive allele to express an X-linked trait
D) All of these
E) None of these

Question 41

A researcher crosses a white eyed female Drosophila with a red eyed male.Knowing that the gene for eye color is sex linked,he expects to observe only red-eyed females and white eyed males in the progeny.However,he observes that while most of the progeny are as expected,a small percentage of the females have white eyes.Explain what may have occurred to cause this result.

Question 42

An X chromosome that has been inactivated becomes a(an)___________ in female mammals.

A) Barr body
B) Oncogene
C) Bacteriophage
D) All of these
E) None of these

Question 43

An increase in the activity of X-linked genes in males,as is observed in Drosophila,is known as:

A) Hypoactivation
B) Hyperactivation
C) Mosaicisn
D) None of these
E) All of these

Question 44

A researcher crosses a white eyed female Drosophila with a red eyed male.Knowing that the gene for eye color is sex linked,he expects to observe only red-eyed females and white eyed males in the progeny.However,he observes that while most of the progeny are as expected,a small percentage of the males have red eyes.Explain what may have occurred to cause this result.

Question 45

In mammals Dosage compensation for X-linked genes is achieved by:

A) Hyperactivation of X-linked genes
B) Down regulation of X-linked genes
C) Inactivation of one X-chromosome during early development
D) All of these
E) None of these

Question 46

Female mammals that contain two types of cell lineages in which the paternal X chromosome is inactivated in some cells and the maternal X chromosome is inactivated in others are known as:

A) Genetic twins
B) Genetic mosaics
C) Genetic anomalies
D) None of these
E) All of these

Question 47

A man with hemophilia mates with a woman who is normal but whose father was a hemophiliac,mother was normal,and whose maternal grandmother was a hemophiliac.What percentage of their sons could be hemophiliacs?

Question 48

A woman,with normal vision whose father was colorblind mates with a man who has normal vision.What are the chances that she will have a son who is colorblind?

Question 49

Assume that coat color in cats is an X-linked trait.Briefly explain why only females can exhibit a combination of coat colors (i.e.Calico)whereas normal XY males can only exhibit one

Question 50

Which of the following is a mechanism that can compensate for an abnormal number of sex chromosomes in an individual? 1.Each X-linked gene could work twice as hard in males as it does in females
2)One copy of each X-linked gene could be inactivated in females
3)Each X-linked gene could work half as hard in females as it does in males

A) 1
B) 2
C) 3
D) 1 and 3
E) All of these