Deck 2: Extensions to Mendels Laws

Question 1

If a geneticist were to closely examine the make-up of a single autosomal chromosome from one of your cells,that chromosome would be found to be

A) derived entirely from genes from just one of your grandparents.
B) a mosaic of genes derived from your mother and father.
C) a mosaic of genes derived from all four of your grandparents.
D) a mosaic of genes derived from just two of your grandparents-either your two grandfathers or your two grandmothers.
E) a mosaic of genes derived from just two of your grandparents-either your maternal grandparents or your paternal grandparents.

Answer 1

E

Question 2

The chromosomal structure to which spindle fibers attach during the mitotic divisions is referred to as a

A) chromatid
B) centrosome
C) kinetochore
D) metaphase plate
E) centromere

Answer 2

C

Question 3

Drosophila melanogaster has four pairs of chromosomes.Sperm from this species are formed by a meiotic process in which homologous chromosomes pair and segregate but do not undergo crossing-over.How many genetically different kinds of sperm could be produced by a Drosophila melanogaster male?

A) 4
B) 8
C) 16
D) 64
E) 256

Answer 3

C

Question 4

If you are a male,your X chromosome contains genes derived from

A) your paternal grandfather only
B) your maternal grandfather only
C) both your paternal and maternal grandfathers
D) both your paternal grandfather and grandmother
E) both your maternal grandfather and grandmother

Question 5

Which type of chromosome provides the basis for sex determination in many sexually reproducing organisms?

A) haploid
B) diploid
C) autosomes
D) sex chromosomes
E) homologous chromosomes

Question 6

The stage of mitosis when chromosomes condense to form rod-shaped structures visible under the microscope is called

A) interphase
B) prophase
C) metaphase
D) anaphase
E) telophase

Question 7

The stage of mitosis when sister chromatids separate from each other and migrate to opposite poles of a cell is called

A) interphase
B) prophase
C) metaphase
D) anaphase
E) telophase

Question 8

Crossing-over between homologous chromosomes occurs at which of the following stages of meiosis?

A) S phase
B) prophase I
C) metaphase I
D) anaphase I
E) prophase II

Question 9

Nondisjunction can occur at either the first or second division of meiosis.XXY individuals could arise from nondisjunction at the ______ meiotic division in the _____.

A) first;mother
B) second;mother
C) first;father
D) second;father
E) more than one of the choices could give rise to XXY individuals

Question 10

A chromosome with two arms of equal length is referred to as

A) acrocentric
B) homologous
C) telocentric
D) metazoan
E) metacentric

Question 11

In Drosophila virilis,nuclei of somatic cells contain 12 chromosomes while nuclei of sperm cells contain only 6 chromosomes.What does "n" equal for this species?

A) 3
B) 6
C) 12
D) 24
E) 6 or 12,depending on cell type

Question 12

Which of the following events occurs during mitosis but not during meiosis?

A) segregation of sister chromatids
B) pairing of homologous chromosomes
C) crossing-over between homologous chromosomes
D) alignment of chromosomes on the metaphase plate
E) None of the choices are correct

Question 13

Humans have 22 pairs of autosomes plus one sex chromosome pair.How many autosomes are present in a normal human primary spermatocyte?

A) 22
B) 23
C) 44
D) 45
E) 46

Question 14

Which of the following statements applies to homologous chromatids?

A) They are attached to the same centromere.
B) They are genetically identical.
C) They segregate from each other at anaphase of mitosis.
D) They contain the same genes in the same order but may have different alleles of some genes.
E) More than one statement applies to homologous chromatids.

Question 15

Nondisjunction can occur at either the first or second division of meiosis.XYY individuals would most likely arise from nondisjunction at the ______ meiotic division in the _____.

A) first;mother
B) second;mother
C) first;father
D) second;father
E) more than one of the choices could give rise to XYY individuals

Question 16

The mitotic stage during which chromosomes begin attaching to spindle fibers and moving randomly and reversibly to the centrosomes is

A) prophase
B) prometaphase
C) metaphase
D) anaphase
E) telophase

Question 17

The cells in which meiosis occurs in males are referred to as

A) spermatocytes
B) spermatogonia
C) spermatids
D) oocytes
E) sperm

Question 18

During which of the following stages of the cell cycle would a chromosome consist of only a single chromatid?

A) G₁
B) G₂
C) mitotic prophase
D) mitotic metaphase
E) S

Question 19

Premeiotic germ cells that divide mitotically in females are referred to as

A) primary oocytes
B) secondary oocytes
C) ootids
D) oogonia
E) ova

Question 20

At which of the following stages of meiosis would homologous chromosomes be paired?

A) prophase of meiosis I
B) prophase of meiosis II
C) metaphase of meiosis I
D) metaphase of meiosis II
E) both prophase of meiosis I and metaphase of meiosis I

Question 21

Suppose you discover a new species of worm that exists in two forms-slimy and non-slimy.You find that mating slimy females with non-slimy males produces offspring consisting of slimy males and non-slimy females,whereas mating non-slimy females with slimy males produces offspring of both sexes that are all slimy.You would conclude that the _________ allele is dominant and that ________ are the heterogametic sex (the sex with two different sex chromosomes)in this species of worm.

A) slimy;females
B) slimy;males
C) non-slimy;females
D) non-slimy;males
E) impossible to determine without further information

Question 22

In chickens,it is the females that have two different sex chromosomes (Z and W)while the males have two Z chromosomes.A Z-linked gene controls the pattern of the feathers,with the dominant B allele causing the barred pattern and the b allele causing nonbarred feathers.From which of the following crosses would all of the daughters be of one type (barred or nonbarred)and all of the sons the other type?

A) barred females × nonbarred males
B) nonbarred females × barred males
C) nonbarred females × nonbarred males
D) barred females × barred males
E) More than one of the choices are correct.

Question 23

A white-eyed female fruit fly is mated to a red-eyed male.One of their progeny is a white-eyed female.This white-eyed daughter likely arose from nondisjunction of the sex chromosomes during _________ in the _________.

A) meiosis I;mother
B) meiosis II;mother
C) meiosis I;father
D) meiosis II;father
E) meiosis I or II;mother

Question 24

Suppose you discover a new variant in which mice have spiky fur instead of the usual soft fur.You notice that this trait seems only to be present in males.To investigate this pattern,you cross a spiky-fur male with a soft-fur female,and find that all of the F₁ progeny of both sexes have soft fur.You then interbreed the F₁ and observe that all of the F₂ females have soft fur,but 1/4 of the F₂ males have spiky fur.You conclude that the spiky allele is

A) an X-linked recessive.
B) Y-linked.
C) an autosomal recessive with sex-limited expression.
D) an X-linked dominant.
E) an autosomal dominant with sex-limited expression.

Question 25

In fruit flies,brown eyes can be caused by the recessive mutations pn (prune),bw (brown),or ry (rosy),which are on the X chromosome,second chromosome,and third chromosome,respectively.Wild-type alleles for all three genes must be present for eyes to be red.Suppose that two brown-eyed flies are crossed and their progeny consist of brown-eyed sons and red-eyed daughters.Which mutation is responsible for the brown eyes in the parental female?

A) pn
B) bw
C) ry
D) either bw or ry
E) any of the three-pn,bw,or ry

Question 26

Microtubules that attach to centrosomes but not chromosomes and that interdigitate with microtubules emanating from the centrosome at the opposite pole are known as

A) kinetochore microtubules
B) polar microtubules
C) astral microtubules
D) interdigitating microtubules
E) None of the choices are correct

Question 27

In Drosophila,the recessive allele for forked bristles is sex-linked,and the recessive allele for purple eyes is autosomal.The wild-type alleles are for straight bristles and red eyes,respectively.A female,heterozygous for both pairs of alleles,is mated with a male with forked bristles and purple eyes.What percentage of the daughters will have forked bristles and purple eyes?

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

Question 28

Red-green colour blindness is controlled by an X chromosome gene in humans.A normal man and normal woman whose fathers are both colour-blind marry.What is the probability that their first child will be colour-blind?

A) 1/2
B) 1/4
C) 1/8
D) 1/3
E) 0

Question 29

Mitosis results in _______ chromosome number,whereas meiosis results in _______ chromosome number.

A) a doubling of;no change in
B) no change in;no change in
C) a reduction by half in;no change in
D) no change in;a doubling of
E) no change in;a reduction by half in

Question 30

A cross between a white-eyed female fruit fly and a red-eyed male would generate which of the following types of progeny?

A) red-eyed females and white-eyed males
B) white-eyed females and red-eyed males
C) all red-eyed females and a 50:50 mixture of white-eyed and red-eyed males
D) all red-eyed males and a 50:50 mixture of white-eyed and red-eyed females
E) The result cannot be predicted because it depends on whether the female is homozygous or heterozygous.

Question 31

What aspect of chromosome behaviour most clearly accounts for Mendel's law of segregation?

A) Movement of sister chromatids to opposite poles at anaphase II of meiosis
B) Movement of homologous chromosomes to opposite poles at anaphase I of meiosis
C) Crossing-over between homologous chromosomes during prophase I of meiosis
D) Replication of chromosomes prior to meiosis
E) Independent alignment of different homologous pairs on the metaphase I spindle

Question 32

Males with one copy of an X-linked gene are said to be _________ for that gene.

A) homozygous
B) heteroallelic
C) heterozygous
D) hemizygous
E) deficient

Question 33

A female fruit fly with singed bristles was mated with a male from a true-breeding wild-type stock with long bristles.All of the F₁ females had wild-type bristles and all of the F₁ males had singed bristles.If the F₁ flies are intercrossed,the expected ratio of long to singed bristles in the F₂ flies is

A) 1:0 in both sexes (i.e. ,males and females will all have long bristles).
B) 3:1 in both sexes.
C) 3:1 in females,while all the males will have singed bristles.
D) 1:1 in females,while all the males will have singed bristles.
E) 1:1 in both sexes.

Question 34

Cells said to be in the G₀ stage

A) have two chromatids per chromosome.
B) are replicating their chromosomes.
C) are about to enter the mitotic phase of the cell cycle.
D) are in an extended G₁ phase and no longer cycling.
E) are dead.

Question 35

A white-eyed female fruit fly is mated to a red-eyed male.One of their progeny is a white-eyed female.What is the likely karyotype of this white-eyed offspring?

A) XX
B) XXY
C) XO
D) XXX
E) XYY

Question 36

Which of the following is not a property of homologous chromosomes?

A) They pair physically during prophase of meiosis I.
B) They exchange genes by crossing-over during meiosis.
C) They carry alleles for the same genes at the same chromosomal position.
D) They are attached to the same centromere during G₂ of the cell cycle.
E) They segregate to opposite poles at anaphase of meiosis I.

Question 37

A variable feature of some chromosomes in corn is the presence or absence of knobs at particular sites.Suppose that one member of each of two pairs of chromosomes in a corn plant has a knob.If this plant is crossed with a knobless plant,what percentage of the offspring is expected to be knobless?

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

Question 38

Cells in the G₂ stage of the cell cycle have ______ as cells of the same species in the G₁ stage.

A) twice as many chromosomes
B) twice as many chromatids
C) half as many chromatids
D) the same number of chromatids
E) half as many chromosomes

Question 39

Haemophilia is caused by an X-linked recessive mutation in humans.If a woman whose paternal uncle (father's brother)was a haemophiliac marries a man whose brother is also a haemophiliac,what is the probability of their first child having haemophilia? Assume that there are no other cases of haemophilia in the pedigree and no hidden carriers.

A) 0
B) 1/4
C) 1/2
D) 1/8
E) 1

Question 40

Colour vision depends upon the dominant alleles of three genes: the R gene and the G gene are both on the X chromosome,while the B gene is autosomal.Recessive mutations in any of the three genes can cause colour blindness.Suppose a colour-blind man marries a colour-blind woman and all of their offspring have normal vision.What is the genotype of the woman?

A) RRGGbb
B) RRggBB
C) rrGGbb
D) RRggBB or RRGGbb
E) rrGGbb or rrggBB

Question 41

Individuals with an XXY karyotype are ______ in humans and ______ in fruit flies.

A) male;male
B) male;female
C) female;male
D) female;female
E) male;intersexual

Question 42

In the following pedigree,the indicated trait is caused by which type of allele? Assume the trait is fully penetrant.

A) autosomal recessive
B) autosomal dominant
C) X-linked recessive
D) X-linked dominant
E) Y-linked

Question 43

In the following pedigree,the indicated trait is caused by which type of allele? Assume the trait is fully penetrant and that the trait is rare in the population,so that alleles for the trait are not carried by anyone who is not the progeny of a mating shown in the pedigree.

A) autosomal recessive
B) Y-linked dominant
C) X-linked recessive
D) X-linked dominant
E) Y-linked recessive

Question 44

Which sex chromosomes are limited to only one sex?

A) X and Z
B) X and W
C) Y and Z
D) Y and W
E) X and Y

Question 45

In humans,XO individuals are females with Turner's syndrome and XXY individuals are males with Klinefelter syndrome.Which of the following events may not give rise to a Klinefelter male?

A) nondisjunction at meiosis I in the mother
B) nondisjunction at meiosis II in the mother
C) nondisjunction at meiosis I in the father
D) nondisjunction at meiosis II in the father
E) All of the choices could give rise to a Klinefelter male.

Question 46

What aspect of chromosome behaviour most clearly accounts for Mendel's law of independent assortment?

A) Movement of sister chromatids to opposite poles at anaphase II of meiosis
B) Movement of homologous chromosomes to opposite poles at anaphase I of meiosis
C) Crossing-over between homologous chromosomes during prophase I of meiosis
D) Replication of chromosomes prior to meiosis
E) Independent alignment of different homologous pairs on the metaphase I spindle

Question 47

A cell with three pairs of chromosomes has the genotype AaBbCc,such that each pair of alleles is on a different pair of chromosomes.If this cell were to undergo meiotic division,how many genetically different types of gametes could be produced?

A) 1
B) 3
C) 6
D) 8
E) 9

Question 48

The literal meaning of chromosome is

A) paired element
B) inheritance factor
C) coloured body
D) recombination
E) small animal

Question 49

A multinucleate plant tissue is called a

A) paranucleus
B) mitocyte
C) meiocyte
D) syncytium
E) coenocyte

Question 50

Which aspect(s)of chromosome behaviour is/are primarily responsible for the tremendous amount of genetic variability associated with sexual reproduction?

A) Segregation of sister chromatids at anaphase II of meiosis
B) Segregation of homologous chromosomes at anaphase I of meiosis
C) Crossing-over between homologous chromosomes during prophase I of meiosis
D) Independent alignment of different homologous pairs on the metaphase I spindle
E) Both crossing-over between homologous chromosomes during prophase I of meiosis and independent alignment of different homologous pairs on the metaphase I spindle contribute to genetic variability

Question 51

A female fruit fly with vermilion eyes and normal wings is crossed with a male with normal red eyes and cut wings.The F₁ progeny consist of females with red eyes and normal wings,and males with vermilion eyes and normal wings.When the F₁ progeny are interbred,the F₂ consists of two types of females-vermilion eyes,normal wings (1/2)and red eyes,normal wings (1/2),and two types of males-vermilion eyes,normal wings (1/2)and red eyes,cut wings (1/2).Are the genes for eye colour and wing type X-linked or autosomal?

A) The eye-colour gene is X-linked and the wing-type gene is autosomal.
B) The eye-colour gene is autosomal and the wing-type gene is X-linked.
C) Both genes are X-linked.
D) Both genes are autosomal.
E) More than one of the choices is consistent with the data.

Question 52

In the following pedigree,the indicated trait is caused by which type of allele? Assume the trait is fully penetrant and that the trait is rare in the population,so that alleles for the trait are not carried by anyone who is not the progeny of a mating shown in the pedigree.

A) autosomal recessive
B) autosomal dominant
C) X-linked recessive
D) X-linked dominant
E) Y-linked

Question 53

In animal gametogenesis,a single primary spermatocyte generates ______ sperm(s),while a single primary oocyte generates ______ egg(s).

A) 1;4
B) 1;1
C) 4;2
D) 4;1
E) 4;4

Question 54

Here is a list of meiotic events in no particular order.
A: Segregation of homologous chromosomes to opposite poles.
B: Segregation of sister chromatids to opposite poles.
C: Alignment of homologous pairs on the midplate of the cell.
D: Pairing and synapsis of homologous chromosomes.
E: Condensation of chromosomes in a diploid nucleus.
What is the correct order of events?

A) CDEAB
B) DCEBA
C) EDCBA
D) EDCAB
E) DCABE

Question 55

In the following pedigree,the indicated trait is caused by which type of allele? Assume the trait is fully penetrant and that the trait is rare in the population,so that alleles for the trait are not carried by anyone who is not the progeny of a mating shown in the pedigree.

A) autosomal recessive
B) autosomal dominant
C) X-linked recessive
D) X-linked dominant
E) Y-linked

Question 56

A cell with three pairs of chromosomes has the genotype AaBbCc,such that each pair of alleles is on a different pair of chromosomes.If this cell were to undergo mitotic division,how many genetically different types of gametes could be produced?

A) 1
B) 3
C) 6
D) 8
E) 9

Question 57

The following is a list of mitotic events in no particular order.
A: Chromosomes align on the midplate of the cell.
B: Kinetochores begin attaching to spindle fibers.
C: Nuclear membrane reforms and chromosomes decondense.
D: Chromosomes condense and centrosomes migrate to opposite sides of nucleus.
E: Sister chromatids separate and move to opposite poles.
What is the correct order of events?

A) BDACE
B) DABEC
C) DBAEC
D) ABDCE
E) EDBAC

Question 58

In humans,XO individuals are females with Turner syndrome and XXY individuals are males with Klinefelter syndrome.Red-green colour blindness is caused by an X-linked recessive allele.Suppose a colour-blind man and a normal woman with no family history of colour blindness married and had a daughter who was colour-blind and had Turner syndrome.Which event could have given rise to this offspring?

A) nondisjunction at meiosis I in the mother
B) nondisjunction at meiosis II in the mother
C) nondisjunction at meiosis I in the father
D) nondisjunction at meiosis II in the father
E) nondisjunction at either meiosis I or meiosis II in the mother

Question 59

In the following pedigree,the indicated trait is caused by what type of allele? Assume the trait is fully penetrant and that the trait is rare in the population,so that alleles for the trait are not carried by anyone who is not the progeny of a mating shown in the pedigree.

A) autosomal recessive
B) autosomal dominant
C) X-linked recessive
D) X-linked dominant
E) Y-linked

Question 60

In fruit flies,an X-linked dominant mutation (N)causes Notch wings in heterozygous females but is lethal in hemizygous or homozygous condition.What ratio of offspring would be observed in a cross of a Notch female with a normal male?

A) 1/3 Notch females,1/3 normal females,1/3 normal males
B) 1/4 Notch females,1/4 normal females,1/4 Notch males,1/4 normal males
C) 1/2 Notch females,1/2 normal males
D) 1/2 normal females,1/2 Notch males
E) 2/3 Notch females,1/3 normal males

Question 61

A female that is XXO has Turner Syndrome.

Question 62

Which of the following did not directly observe chromosomes to study their role in heredity?

A) Mendel
B) Boveri
C) Sutton
D) Wilson
E) Morgan

Question 63

The nonsex chromosomes are called autosomes.

Question 64

A ____________________________ is an image of all the chromosomes of an organism arranged into pairs based on staining pattern and,by convention,in decreasing size,with sex chromosomes last.

A) karyotype
B) chromogram
C) chromotype
D) genome map
E) linkage map

Question 65

Which of the following helps explain why increased maternal age is correlated with an increased risk of Down syndrome?

A) mutations accumulate in the germ line in a time-dependent manner
B) meiosis in oocytes is incomplete before fertilization
C) frequency of crossovers increases with gamete age
D) barriers to double fertilization decrease in older ova
E) kinetochore fusion is more common in older women

Question 66

How do amniocentesis and chorionic villus sampling (CVS)differ?

A) Only amniocentesis can be used for karyotyping.
B) Only CVS samples are placed in culture medium after collection.
C) Only CVS isolates fetal cells.
D) CVS can detect only Down syndrome,not any other abnormalities.
E) Fewer cells are collected during amniocentesis than during CVS.

Question 67

Sister chromatids are identical chromosomes,duplicated during S-phase and still attached to each other.

Question 68

A chromatin-laden nucleus is quiescent.

Question 69

Which of the following observations was made in the mid-1800s and implied that the nucleus contains the genetic material?

A) The nucleus contains DNA.
B) The nucleus contains chromosomes.
C) Nuclei are the only cellular components contributed equally by egg and sperm.
D) Chromosome number decreases at meiosis.
E) Nuclear DNA content decreases at mitosis.

Question 70

______________________________ occurs when chromosomes fail to separate properly during meiosis.

A) karyogamy
B) synaptonemy
C) pachytene
D) crossover
E) nondisjunction

Question 71

The process of matching chromosomes becoming zipped together during the zygotene stage of prophase I is called

A) crossover
B) recombination
C) morphogenesis
D) synapsis
E) reassortment

Question 72

Which of the following can arrest the cell cycle?

A) failure of a kinetochore to attach to spindle fibers
B) formation of a syncytium
C) formation of a synaptonemal complex
D) breakdown of nucleoli
E) DNA synthesis

Question 73

Which of the following best describes cells that are arrested in G₀?

A) embryonic
B) cancerous
C) germ line
D) somatic
E) syncytial

Question 74

The smaller diploid sister cell that results during meiosis I in females is called a _____________________________.

A) nucleolus
B) Barr body
C) polar body
D) microcyte
E) sister chromatid

Question 75

When do human oocytes normally complete meiosis I?

A) embryogenesis
B) birth
C) puberty
D) ovulation
E) fertilization

Question 76

Chromosomes that carry the same genes,but not necessarily the same alleles are called

A) sister chromatids
B) homologues
C) paralogs
D) parameres
E) chromomeres

Question 77

What are the advantages of chorionic villus sampling (CVS)compared to amniocentesis?

A) Ultrasound imaging is not generally required for CVS.
B) More diseases can be detected using CVS than using amniocentesis.
C) CVS has a significantly low risk of miscarriage.
D) CVS may be performed earlier in pregnancy than amniocentesis.
E) CVS allows diagnosis without karyotyping.

Question 78

In _______________________ chromosomes,the centromere is closer to one end than to the middle.

A) metacentric
B) telocentric
C) acrocentric
D) paracentric
E) acentric

Question 79

A ________________________ is an animal cell with two or more nuclei.

A) sporocyte
B) coenocyte
C) cytomere
D) polyploid
E) syncytium

Question 80

Which of the following best describes a collection of animal embryonic cells that undergoes mitotic divisions to yield specialized diploid cells,which undergo meiosis?

A) corpus luteum
B) germ line
C) oocyte
D) ova
E) spermatocyte