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1 | |
Mendel's idea that pairs of characters separate during gamete formation is called the law of |
| | A) | particulate inheritance. |
| | B) | dominance. |
| | C) | segregation. |
| | D) | independent assortment. |
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2 | |
The allele that masks the effects of the other is ____ and the masked allele is ____. |
| | A) | homozygous, heterozygous |
| | B) | homozygous, recessive |
| | C) | dominant, recessive |
| | D) | dominant, incomplete |
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3 | |
True-breeding plants are always |
| | A) | homozygous for the dominant allele. |
| | B) | homozygous for the recessive allele. |
| | C) | heterozygous. |
| | D) | homozygous. |
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4 | |
What is the most common outcome in the F2 generation of a cross between a tall plant and a dwarf plant? |
| | A) | 1 tall : 1 dwarf |
| | B) | 3 tall : 1 dwarf |
| | C) | 1 tall : 2 medium : 1 dwarf |
| | D) | all tall |
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5 | |
Two carriers of albinism have four children. One of their children is albino and the remaining three are normally pigmented. What is the probability that their next child will be albino? |
| | A) | 0 % |
| | B) | 25 % |
| | C) | 75 % |
| | D) | 100 % |
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6 | |
Kathy's brother has cystic fibrosis. Her husband has no family history of cf. What is the chance that Kathy's child has inherited the cystic fibrosis allele? |
| | A) | 1/2 x 1/2 = 1/4 |
| | B) | 1/3 x 1/2 = 1/6 |
| | C) | 2/3 x 1/4 = 1/6 |
| | D) | 2/3 x 1/2 = 1/3 |
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7 | |
The occurrence of affected individuals in every generation in a family suggests ____ trait. |
| | A) | an autosomal dominant |
| | B) | an autosomal recessive |
| | C) | either dominant or recessive |
| | D) | sex-linked |
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8 | |
Which of the following is an example of a cross between two dihybrids? |
| | A) | AaBb x aabb |
| | B) | AaBb x AaBb |
| | C) | aabb x AABB |
| | D) | aabb x aabb |
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9 | |
Which of the following phenotypic results is expected from a cross between two dihybrids? |
| | A) | 1:1:1:1 ratio |
| | B) | 9:3:3:1 ratio |
| | C) | all dominant for both traits |
| | D) | all recessive for both traits |
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10 | |
Mendel's law of ____ states that a random assortment of maternally and paternally derived chromosomes in meiosis results in gametes that have different combinations of alleles. |
| | A) | particulate inheritance |
| | B) | dominance |
| | C) | segregation |
| | D) | independent assortment |
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11 | |
Which of the following incorrectly identifies the mode of inheritance for the given genetic disease? |
| | A) | ataxia telangiectasis — recessive |
| | B) | cystic fibrosis — recessive |
| | C) | porphyria variegata — dominant |
| | D) | sickle cell — dominant |
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12 | |
Consider an autosomal dominant trait. If an unaffected parent and an affected heterozygous parent are expecting, what is the chance of them having an unaffected child? |
| | A) | 0% |
| | B) | 25% |
| | C) | 50% |
| | D) | 100% |
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13 | |
Mendel's laws are explained by |
| | A) | chromosome behavior in mitosis. |
| | B) | chromosome behavior in meiosis. |
| | C) | cytokinesis in mitosis and meiosis. |
| | D) | Mendel's laws have not been explained. |
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14 | |
Which genotype is normally not found in a gamete? |
| | A) | AB |
| | B) | Ab |
| | C) | aa |
| | D) | ab |
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15 | |
Which of the following crosses is a test cross? |
| | A) | unknown x AA |
| | B) | unknown x Aa |
| | C) | unknown x aa |
| | D) | unknown x unknown |
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16 | |
Two phenotypically normal individuals have an affected child. What can we conclude about the parents? |
| | A) | they both carried the disease allele |
| | B) | they are not the parents of the child |
| | C) | they are affected |
| | D) | no conclusions can be drawn |
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17 | |
A team of geneticists led by _____ has compiled a compendium of human genetic traits called Mendelian Inheritance in Man (OMIM). |
| | A) | Gregor Mendel |
| | B) | Hermann Muller |
| | C) | Victor McKusick |
| | D) | John Hopkins |
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18 | |
Relatives who have children together have a much higher risk of having children affected by a (an) ____ condition. |
| | A) | environmental |
| | B) | dominant |
| | C) | recessive |
| | D) | undetected |
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19 | |
Consider a group of 100 individuals (50 couples), all of whom carry a recessive disease allele. If 200 children were born to these couples, what percentage of the children would, theoretically, be carriers like their parents? |
| | A) | 0 |
| | B) | 25 |
| | C) | 50 |
| | D) | 75 |
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20 | |
In the cross AaBb x aabb, what percentage of the offspring are expected to show a completely dominant phenotype? |
| | A) | 0 |
| | B) | 25 |
| | C) | 50 |
| | D) | 100 |
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21 | |
Two genes on the same chromosome can appear to assort independently if |
| | A) | they are located very far apart from each other. |
| | B) | they both display autosomal recessive inheritance. |
| | C) | they both display autosomal dominant inheritance. |
| | D) | the individual is heterozygous for both genes. |
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22 | |
Can independent assortment be demonstrated in a monohybrid cross? |
| | A) | yes, you can observe random distribution of alleles into gametes |
| | B) | yes, you can observe random assortment of genes into gametes |
| | C) | no, you must observe genes that are on the same chromosome |
| | D) | no, you must examine the transmission of two or more genes |
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23 | |
The ____ rule of probability is useful in calculating the risk that certain individuals will inherit a particular genotype. |
| | A) | product |
| | B) | summation |
| | C) | additive |
| | D) | none of the above is correct |
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24 | |
Achondroplasia is a dominant form of dwarfism. Two affected individuals have a ____ % chance of having an unaffected child. |
| | A) | 0 |
| | B) | 25 |
| | C) | 50 |
| | D) | 75 |
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25 | |
An adult sibling of a person who is a known carrier of Tay-Sachs disease has a ____ chance of being a carrier. |
| | A) | 1/4 |
| | B) | 1/2 |
| | C) | 1/3 |
| | D) | 2/3 |
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