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1 | |
In humans, males are |
| | A) | homogametic. |
| | B) | heterogametic. |
| | C) | hermaphroditic. |
| | D) | pseudohermaphroditic. |
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2 | |
Male pseudohermaphroditism describes a |
| | A) | female exterior, male interior, and male chromosome constitution. |
| | B) | male exterior, female interior, and female chromosome constitution. |
| | C) | female exterior, female interior, and female chromosome constitution. |
| | D) | male exterior, male interior, and female chromosome constitution. |
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3 | |
An affected male and a normal female have four children: two affected daughters and two normal sons. Each of the affected daughters (and their normal husbands) produced affected sons and affected daughters. The couple's normal sons married normal women and had all normal children. What is the most likely mode of inheritance for this trait? |
| | A) | autosomal dominant |
| | B) | autosomal recessive |
| | C) | sex-linked dominant |
| | D) | sex-linked recessive |
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4 | |
Male pattern baldness is a ____ trait. |
| | A) | sex-linked |
| | B) | sex-limited |
| | C) | sex-influenced |
| | D) | Y-linked |
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5 | |
The probability that a male inherited his Y chromosome from his maternal grandfather is |
| | A) | 0 %. |
| | B) | 25 %. |
| | C) | 50 %. |
| | D) | 100 %. |
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6 | |
How many Barr bodies would be observed in the nucleus of an XXY individual? |
| | A) | 0 |
| | B) | 1 |
| | C) | 2 |
| | D) | 3 |
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7 | |
What would be the sex of an XXY individual? |
| | A) | male |
| | B) | female |
| | C) | hermaphrodite |
| | D) | mosaic |
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8 | |
A female whose father was colorblind marries and normal male whose father was also colorblind. What is the probability that their son will be colorblind? |
| | A) | 0 % |
| | B) | 25 % |
| | C) | 50% |
| | D) | 75% |
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9 | |
A female whose father was colorblind marries and normal male whose father was also colorblind. What is the probability that their daughter will be colorblind? |
| | A) | 0 % |
| | B) | 25 % |
| | C) | 50% |
| | D) | 75% |
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10 | |
A woman whose husband worked at the Chernobyl nuclear reactor gives birth to a hemophiliac son. |
| | A) | She should blame the reactor accident because the radiation caused the hemophilia. |
| | B) | She should not blame the accident because she carried the hemophilia allele. |
| | C) | Her husband should sue for divorce because it cannot be his child. |
| | D) | Further genetic tests should be done to determine who is at fault. |
| | E) | Hemophilia is environmentally induced, not genetic. |
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11 | |
Prader-Willi Syndrome and Angelman Syndrome are both associated with deletions of the same bands from the long arm of chromosome 15. However, the physical expression associated with each disorder is very different. This is an example of |
| | A) | imprinting. |
| | B) | nuclear inheritance. |
| | C) | Mendelian inheritance. |
| | D) | heteroplasmy. |
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12 | |
Sexual identity is determined by the sex chromosome make-up of an individual only. True or false? |
| | A) | true |
| | B) | false |
| | C) | variable |
| | D) | basis is unknown |
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13 | |
The ____ gene on the ____ chromosome determined sex in humans. |
| | A) | SRY, X |
| | B) | SRY, Y |
| | C) | XIST, sex |
| | D) | sex, Y |
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14 | |
A medical condition that arises in the mother during pregnancy is: |
| | A) | a sex-linked trait |
| | B) | a trait determined by mitochondrial DNA |
| | C) | a sex-limited trait |
| | D) | a sex-influenced trait |
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15 | |
Individuals with three copies of most autosomes do not survive. Individuals with an extra X chromosome, however, survive with relatively mild (compared to autosomal abnormalities) consequences. Why? |
| | A) | the X chromosome contains few genes while autosomes contain a large number |
| | B) | the extra X chromosome(s) are inactivated |
| | C) | the X chromosome determines sex only |
| | D) | none of the above |
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16 | |
Which of the following genetic conditions is not sex-linked? |
| | A) | ichthyosis |
| | B) | colorblindness |
| | C) | sickle-cell anemia |
| | D) | a and c |
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17 | |
A woman whose brother has hemophilia is concerned about passing this trait to her offspring. What is the risk that she will have a son with hemophilia? |
| | A) | 1/8 |
| | B) | 1/4 |
| | C) | 1/2 |
| | D) | 1 |
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18 | |
Can a male be a carrier for a sex-linked disease? |
| | A) | yes, if the trait is recessive |
| | B) | yes, if the male's father and mother were carriers |
| | C) | no, males have only a single copy of sex-linked genes |
| | D) | no way to predict |
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19 | |
X-inactivation can be used to identify individuals who are |
| | A) | homozygous unaffected. |
| | B) | heterozygous. |
| | C) | homozygous affected. |
| | D) | missing X-linked genes. |
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20 | |
Calico cats have large patches of coat color. What can we conclude about the timing of X-inactivation? |
| | A) | it occurred early |
| | B) | it occurred late |
| | C) | it occurred both early and late |
| | D) | no relationship exists |
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21 | |
Beard growth in humans is an example of a ____ trait. |
| | A) | sex-linked |
| | B) | sex-influenced |
| | C) | sex-limited |
| | D) | Y-linked |
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22 | |
In humans, the presence of two male pronuclei and no female pronucleus in a fertilized ovum results in the formation of a |
| | A) | normal embryo. |
| | B) | teratoma. |
| | C) | hydatidiform mole. |
| | D) | placental tissue only. |
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23 | |
Consider a sex-linked recessive trait. Which of the following crosses would produce males and females with different phenotypes? |
| | A) | homozygous normal female x normal male |
| | B) | affected female x affected male |
| | C) | affected female x normal male |
| | D) | heterozygous normal female x affected male |
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24 | |
The majority of calico cats are female. However, a few rare males are observed. What is the genotype of a male calico cat? |
| | A) | XBXb |
| | B) | XBY |
| | C) | XbYY |
| | D) | XBXbY |
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25 | |
Once the SRY begins to function, ____ cells begin to secrete anti-Mullerian hormone and ____ cells secrete testosterone. |
| | A) | sustentacular, sertoli |
| | B) | sustentacular, interstital |
| | C) | leydig, sertoli |
| | D) | DHT, sustentacular |
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