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| 1 | |
During the cell cycle, DNA is replicated during the _____ phase, and _____ is the interval between DNA synthesis and mitosis. |
| | A) | S, G0 |
| | B) | S, G1 |
| | C) | S, G2 |
| | D) | G0, G1 |
| | E) | G1, G2 |
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| 2 | |
The nucleus divides during the _____ cell cycle phase and the cytoplasm divides during the _____ cell cycle phase. |
| | A) | G1, G2 |
| | B) | mitosis, cytokinesis |
| | C) | cytokinesis, mitosis |
| | D) | S, telophase |
| | E) | mitosis, mitosis |
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| 3 | |
A cell usually accomplishes most of its growth during: |
| | A) | mitosis |
| | B) | G0 |
| | C) | G1 |
| | D) | G2 |
| | E) | S |
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| 4 | |
The stage of mitosis when the chromosomes condense is called __________, and the stage when the nuclear envelope reforms around the chromosomes is called __________. |
| | A) | anaphase, prophase |
| | B) | prophase, metaphase |
| | C) | prophase, anaphase |
| | D) | prophase, telophase |
| | E) | metaphase, telophase |
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| 5 | |
The stage of mitosis when the chromosomes align between the spindle poles is called __________, and the stage when the chromosomes begin to separate is called __________. |
| | A) | metaphase, anaphase |
| | B) | metaphase, telophase |
| | C) | metaphase, prophase |
| | D) | prophase, telophase |
| | E) | prophase, anaphase |
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| 6 | |
During meiosis, pairs of chromosomes align on the spindle during __________, homologous chromosomes pair and cross over during __________. |
| | A) | metaphase I, prophase II |
| | B) | metaphase I, prophase I |
| | C) | metaphase I, metaphase II |
| | D) | metaphase II, prophase I |
| | E) | metaphase II, prophase II |
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| 7 | |
During meiosis, sister chromatids segregate to opposite poles during __________, and homologous chromosomes segregate to opposite poles during __________. |
| | A) | anaphase I, anaphase II |
| | B) | telophase I, telophase II |
| | C) | telophase II, telophase I |
| | D) | anaphase I, telophase II |
| | E) | anaphase II, anaphase I |
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| 8 | |
What aspect of chromosome behavior most clearly accounts for Mendel's law of segregation?
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| | 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. |
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| 9 | |
Which of the following does not occur in mitosis?
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| | A) | Chromosomes condense, centrosomes migrate to opposite sides of nucleus. |
| | B) | Kinetochores begin attaching to spindle fibers. |
| | C) | Chromosomes align on the midplate of the cell. |
| | D) | Pairing and synapsis of homologous chromosomes |
| | E) | Sister chromatids separate, move to opposite poles. |
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| 10 | |
What aspect of chromosome behavior most clearly accounts for Mendel's law of independent assortment?
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| | 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. |
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| 11 | |
If the number of chromosomes in a normal diploid oogonium cell is 2n, how many chromosomes will the oocyte contain after meiosis?
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| | A) | 1/2n |
| | B) | n |
| | C) | 2n |
| | D) | 4n |
| | E) | n2 |
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| 12 | |
You observe the progeny of a Drosophila cross to consist of all red-eyed females and white-eyed males. What do you infer the parental phenotypes to be?
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| | A) | red-eyed females and white-eyed males |
| | B) | red-eyed females and red-eyed males |
| | C) | white-eyed females and white-eyed males |
| | D) | white-eyed females and red-eyed males |
| | E) | b or c |
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| 13 | |
Three male cousins notice that they all have a particular trait that their maternal grandfather had. Two of the cousins are brothers, but all have unaffected brothers and sisters, and no affected parents, uncles, or aunts. What type of allele is being inherited?
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| | A) | autosomal recessive |
| | B) | autosomal dominant |
| | C) | X-linked recessive |
| | D) | X-linked dominant |
| | E) | Y-linked |
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| 14 | |
Hemophilia is caused by an X-linked mutation in humans. If a woman whose maternal uncle (mother's brother), but neither grandparent, was a hemophiliac marries a man whose brother is also a hemophiliac, what is the probability of their first child having hemophilia (assume no other hemophilia in the pedigree and no hidden carriers).
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| | A) | 0 |
| | B) | 1/4 |
| | C) | 1/2 |
| | D) | 1/8 |
| | E) | 1/16 |
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| 15 | |
Red-green color-blindness is controlled by an X chromosomal gene in humans. A normal man whose father is color-blind marries a woman whose mother is color-blind. What is the probability that their first child will be color-blind?
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| | A) | 1/2 |
| | B) | 1/4 |
| | C) | 1/8 |
| | D) | 1/3 |
| | E) | 0 |
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| 16 | |
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 non-barred feathers. You cross a barred female with a non-barred male. What do you expect for the phenotype of the progeny?
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| | A) | daughters all one type, sons all the other type |
| | B) | daughters and sons of both types |
| | C) | sons of one type, daughters of both types |
| | D) | daughters of one type, sons of both types |
| | E) | none of the above |
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| 17 | |
Suppose you discover a new variant in which hamsters have long tails instead of the usual stubby tails. You notice that this trait seems only to be present in males. To investigate this pattern, you cross a long-tail male with a true-breeding stubby-tail female, and find that all of the F1 progeny of both sexes have stubby tails. You then interbreed the F1 and observe that all of the F2 females have stubby tails, but 1/4 of the F2 males have long tails. You conclude that:
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| | A) | the long allele is an X-linked recessive. |
| | B) | the long allele is Y-linked. |
| | C) | the long allele is autosomal recessive with sex-limited expression. |
| | D) | the long allele is an X-linked dominant. |
| | E) | the long allele is an autosomal dominant with sex-limited expression. |
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| 18 | |
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 by a normal male?
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| | 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 |
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| 19 | |
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:
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| | 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. |
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| 20 | |
Color 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 color-blindness. Suppose a colorblind man marries a colorblind woman and all of their offspring (4 sons and 2 daughters) have normal vision. What is the genotype of the man with respect to the autosomal locus?
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| | A) | BB |
| | B) | Bb |
| | C) | bb |
| | D) | a or b |
| | E) | cannot be determined |
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| 21 | |
You are studying a new species of toad that exists in two forms: bumpy and smooth. You find that when bumpy females are mated to smooth males the offspring consist of bumpy males and smooth females, whereas when smooth females are mated with bumpy males, the offspring of both sexes are all bumpy. All strains mated are true-breeding. You would conclude that the _________ allele is dominant and that ________ are the heterogametic sex (the sex with two different sex chromosomes) in this species.
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| | A) | bumpy, females |
| | B) | bumpy, males |
| | C) | smooth, females |
| | D) | smooth, males |
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| 22 | |
In humans, XXY individuals are males with Klinefelter's syndrome. Which of the following events could not give rise to a Klinefelter's male?
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| | 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 above could give rise to a Klinefelter's male. |
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| 23 | |
In humans, XO individuals are females with Turners syndrome. Red-green color blindness is caused by an X-linked recessive allele. Suppose a colorblind man and a woman who is normal with no history of color-blindness married and had a daughter who had Turner's syndrome. Assuming an equal chance of nondisjunction arising from either parent, what is the likelihood that the daughter is also color-blind?
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| | A) | 1/16 |
| | B) | 1/8 |
| | C) | 1/4 |
| | D) | 1/2 |
| | E) | 1 |
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| 24 | |
Both muscular dystrophy and color blindness are X-linked recessive traits. A color-blind man marries a woman who is a carrier for muscular dystrophy. Both the man and woman have a normal karyotype. The couple decides to have a child. Which of the listed children represents the phenotype least likely to occur?
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| | A) | A Klinefelter syndrome (XXY) son with muscular dystrophy. |
| | B) | A Turner syndrome (XO) color-blind daughter. |
| | C) | An XX daughter with muscular dystrophy. |
| | D) | A triplo-X daughter who is otherwise normal. |
| | E) | An XYY son with muscular dystrophy. |
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| 25 | |
C. elegans nematodes exist as self-fertilizing hermaphrodites with two X chromosomes (XX) and males with only one X chromosome (XO). Normally, hermaphrodites produce only XX self progeny hermaphrodites. A mutation in the autosomal gene him-8 (high incidence of males) gene causes frequent X-chromosome non-disjunction events during meiosis, creating nullo-X gametes and resulting in many male (XO) progeny. unc-18 is a gene on the X chromosome; mutations in it cause animals to be uncoordinated. dpy-17 is a gene on chromosome III; mutations in it cause animals to be dumpy. Mutations in unc-18, dpy-17 and him-8 are all recessive. If wild-type males are crossed into hermaphrodites that are homozygous for all three mutations. what types of phenotypes will you see among the cross progeny?
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| | A) | wild-type males and hermaphrodites |
| | B) | uncoordinated males and hermaphrodites |
| | C) | uncoordinated males and wild-type hermaphrodites |
| | D) | wild-type males and uncoordinated hermaphrodites |
| | E) | a and b |
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