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| 1 | |
If Mendel had been working with genes on the same chromosome, he would not have been able to formulate his laws of segregation and independent assortment. |
| | A) | True |
| | B) | False |
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| 2 | |
The term X-linked is used for genes carried on the Y chromosome. |
| | A) | True |
| | B) | False |
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| 3 | |
Which of the following supports the chromosomal theory of inheritance? |
| | A) | both chromosomes and alleles are paired in diploid cells |
| | B) | homologous chromosomes and alleles separate during meiosis |
| | C) | fertilization restores both the diploid chromosome number and allele pairs in the zygote. |
| | D) | all of the above |
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| 4 | |
Who determines the sex of the child? |
| | A) | the male |
| | B) | the female |
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| 5 | |
In animals, the autosomes are different in males than they are in females. |
| | A) | True |
| | B) | False |
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| 6 | |
The sex chromosomes of a human female are _____. |
| | A) | XX |
| | B) | XY |
| | C) | YY |
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| 7 | |
Females can only produce gametes with an X chromosome. |
| | A) | True |
| | B) | False |
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| 8 | |
Traits which are X-linked are expressed more frequently by males. |
| | A) | True |
| | B) | False |
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| 9 | |
Male and female Drosophila flies have _____. |
| | A) | the same number of chromosomes as humans |
| | B) | one pair of sex chromosomes |
| | C) | the same number of sex chromosomes as humans |
| | D) | both B and C |
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| 10 | |
The allele for Drosophila eye color ____. |
| | A) | is on the Y chromosome |
| | B) | is on the X chromosome |
| | C) | is on one of its autosomes |
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| 11 | |
The sex chromosomes carry genes for traits that have nothing to do with the sex of the organism in addition to those genes that determine sex. |
| | A) | True |
| | B) | False |
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| 12 | |
Mendel's factors are now called alleles. |
| | A) | True |
| | B) | False |
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| 13 | |
Which of the following best describes a Drosophila with the genotype XRXr assuming XR = red eyes and Xr = white eyes? |
| | A) | female with red eyes |
| | B) | female that is a carrier |
| | C) | male with white eyes |
| | D) | both A and B |
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| 14 | |
Assuming XR = red eyes and Xr = white eye, what is the phenotype of an individual with the genotype XrY? |
| | A) | male with red eyes |
| | B) | male with white eyes |
| | C) | female with red eyes |
| | D) | female with white eyes |
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| 15 | |
An individual with the genotype XrY will produce which of the following gametes? |
| | A) | XR |
| | B) | Xr |
| | C) | Y |
| | D) | both B and C |
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| 16 | |
If XR = red eyes and Xr = white eyes, will the Drosophila cross of XRXR x XrY produce white-eyed males? |
| | A) | yes |
| | B) | no |
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| 17 | |
Color blindness in humans is X-linked. If XB = normal vision and Xb = color blindness, will an organism with the genotype XBXb be color blind? |
| | A) | yes |
| | B) | no |
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| 18 | |
Carriers do not display the recessive phenotype but are able to pass on an allele for the recessive phenotype to their offspring. |
| | A) | True |
| | B) | False |
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| 19 | |
If XB = normal vision and Xb = color blindness, what are the chances a color blind female will have color blind sons if she has children with a man with normal vision? |
| | A) | 100% |
| | B) | 50% |
| | C) | 25% |
| | D) | none |
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| 20 | |
What are the chances of a female, homozygous for normal vision, and a color blind male having color blind daughters? |
| | A) | 100% |
| | B) | 50% |
| | C) | 25% |
| | D) | none |
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| 21 | |
Carriers can also be described as _____. |
| | A) | homozygous recessive |
| | B) | homozygous dominant |
| | C) | heterozygous |
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| 22 | |
Linked alleles tend to stay together and do not separate independently, as predicted by Mendel's laws. |
| | A) | True |
| | B) | False |
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| 23 | |
There is a direct relationship between the frequency of crossing-over and the percentage of recombinant __________. |
| | A) | gametes |
| | B) | phenotypes |
| | C) | genotypes |
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| 24 | |
The chromosomes can be mapped by determining the frequency of recombinant _____ that occurs due to the process of crossing over. |
| | A) | gametes |
| | B) | phenotypes |
| | C) | genotypes |
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| 25 | |
Drosophila chromosome II carries the gene for _____. |
| | A) | antennae type |
| | B) | wing type |
| | C) | leg length |
| | D) | all of the above |
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| 26 | |
If crossing over occurs between two linked alleles of interest, a dihybrid produces _____ type(s) of gamete(s). |
| | A) | one |
| | B) | two |
| | C) | three |
| | D) | four |
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| 27 | |
When chromosomes are mapped by examining recombinant phenotypes, it is assumed that 1% of crossing over equals _____ map unit(s). |
| | A) | one |
| | B) | two |
| | C) | five |
| | D) | ten |
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| 28 | |
When individuals heterozygous for two traits that have linked alleles are crossed the expected phenotypic ratio of the offspring is _____. |
| | A) | 1:1:1:1 |
| | B) | 1:1 |
| | C) | 3:1 |
| | D) | 9:3:3:1 |
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| 29 | |
When a cross involving mutant genes b and e is done 3% recombinants are observed. When a cross involving mutant genes t and e is done 22% recombinants are observed. When a cross involving mutant genes b and t is done 19% recombinants are observed. What is the correct order of the genes on the chromosome? |
| | A) | t, b, e |
| | B) | b, t, e |
| | C) | t, e, b |
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| 30 | |
Mutations increase the amount of variation among offspring. |
| | A) | True |
| | B) | False |
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| 31 | |
It is estimated that __________ of all flowering plants are polyploids. |
| | A) | 21% |
| | B) | 47% |
| | C) | 68% |
| | D) | 92% |
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| 32 | |
Triploids have _____ of each kind of chromosome. |
| | A) | one |
| | B) | two |
| | C) | three |
| | D) | four |
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| 33 | |
Nondisjunction can occur during meiosis I if _____. |
| | A) | members of a homologous pair fail to separate |
| | B) | the daughter chromosomes fail to separate and instead go into the same daughter cell |
| | C) | both A and B |
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| 34 | |
Nondisjunction more commonly occurs during mitosis than during meiosis. |
| | A) | True |
| | B) | False |
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| 35 | |
When an individual has only one of a particular type of chromosome it's described as _____. |
| | A) | monosomy |
| | B) | disomy |
| | C) | trisomy |
| | D) | tetrasomy |
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| 36 | |
Down syndrome is a _____. |
| | A) | monosomy |
| | B) | disomy |
| | C) | trisomy |
| | D) | tetrasomy |
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| 37 | |
In humans, Turner syndrome _____. |
| | A) | is a monosomy |
| | B) | involves the sex chromosomes |
| | C) | results in a female |
| | D) | all of the above |
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| 38 | |
Nondisjunction can occur during _____. |
| | A) | anaphase I |
| | B) | anaphase II |
| | C) | both A and B |
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| 39 | |
A trisomy occurs when an individual has three of _____. |
| | A) | a particular type of chromosome |
| | B) | each kind of chromosome |
| | C) | both A and B |
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| 40 | |
A trisomic individual is more likely to survive than a monosomic one. |
| | A) | True |
| | B) | False |
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| 41 | |
Polyploidy generally results from _____. |
| | A) | mutation |
| | B) | hybridization |
| | C) | nondisjunction |
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| 42 | |
Both members of a pair of chromosomes must experience a deletion for abnormalities to occur. |
| | A) | True |
| | B) | False |
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| 43 | |
A(n) _____ is the movement of a segment of a chromosome from one chromosome to another nonhomologous chromosome. |
| | A) | inversion |
| | B) | translocation |
| | C) | deletion |
| | D) | duplication |
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| 44 | |
When a broken segment from one chromosome attaches to its homologue a(n) _____ occurs. |
| | A) | duplication |
| | B) | deletion |
| | C) | inversion |
| | D) | both A and B |
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| 45 | |
Which of the following may result in abnormal gametes and offspring? |
| | A) | inversion |
| | B) | translocation |
| | C) | deletion |
| | D) | all of the above |
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| 46 | |
The patterns of inheritance that Mendel formulated have no application to the modern study of genetics. |
| | A) | True |
| | B) | False |
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| 47 | |
Human genes and chromosomes obey the same laws of inheritance that other species obey. |
| | A) | True |
| | B) | False |
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| 48 | |
Down syndrome that tends to run in the family of either the mother or father is the result of _____. |
| | A) | deletion |
| | B) | inversion |
| | C) | duplication |
| | D) | translocation |
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| 49 | |
Cri du chat syndrome is the result of a(n) _____. |
| | A) | inversion |
| | B) | translocation |
| | C) | deletion |
| | D) | duplication |
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| 50 | |
Inversions don't cause any abnormalities since the same genes are present in the chromosome. |
| | A) | True |
| | B) | False |
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| 51 | |
Chromosomes may be broken by _____. |
| | A) | viruses |
| | B) | radiation |
| | C) | certain organic chemicals |
| | D) | all of the above |
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| 52 | |
A(n) _____ occurs when a segment of chromosome is turned around 180o. |
| | A) | inversion |
| | B) | translocation |
| | C) | deletion |
| | D) | duplication |
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| 53 | |
A process of _____ followed by different mutations in each gene may be the cause of the presence of several closely linked genes for human globin. |
| | A) | inversion |
| | B) | translocation |
| | C) | deletion |
| | D) | duplication |
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| 54 | |
Somatic cells in humans have __________ chromosomes. |
| | A) | 23 |
| | B) | 46 |
| | C) | 92 |
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| 55 | |
When a karyotype is done chromosomes are arranged in pairs based on _____. |
| | A) | size |
| | B) | shape |
| | C) | centromere location |
| | D) | all of the above |
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| 56 | |
In human females the sex chromosomes are identical in size, shape and centromere location. |
| | A) | True |
| | B) | False |
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| 57 | |
A display of the pairs of chromosomes is called a _____. |
| | A) | pedigree chart |
| | B) | karyotype |
| | C) | caricature |
| | D) | chromosome map |
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| 58 | |
Fetal cells can be obtained for diagnostic purposes during _____. |
| | A) | chorionic villi sampling |
| | B) | fertilization |
| | C) | amniocentesis |
| | D) | both A and C |
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| 59 | |
Nondisjunction leading to the birth of a child with an abnormal number of chromosomes occurs only during spermatogenesis. |
| | A) | True |
| | B) | False |
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| 60 | |
In humans there are _____ pairs of autosomes. |
| | A) | 22 |
| | B) | 23 |
| | C) | 44 |
| | D) | 88 |
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| 61 | |
Nondisjunction _____. |
| | A) | results in gametes with too few chromosomes |
| | B) | can occur during meiosis I |
| | C) | can occur during meiosis II |
| | D) | all of the above |
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| 62 | |
The chances of a woman having a Down syndrome child decrease with age. |
| | A) | True |
| | B) | False |
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| 63 | |
The most common autosomal trisomy among humans is _____. |
| | A) | trisomy 21 |
| | B) | trisomy 13 |
| | C) | trisomy 18 |
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| 64 | |
Persons with Down syndrome usually have __________ copies of chromosome 21 in their karyotype. |
| | A) | two |
| | B) | three |
| | C) | four |
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| 65 | |
Which of the following would be the result of nondisjunction of the sex chromosomes? |
| | A) | Turner syndrome XO |
| | B) | Down syndrome trisomy 21 |
| | C) | Edward syndrome trisomy 18 |
| | D) | Patau syndrome trisomy 13 |
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| 66 | |
XYY males are more likely to be criminally aggressive. |
| | A) | True |
| | B) | False |
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| 67 | |
If an egg with 22 autosomes is fertilized by a sperm with 22 autosomes and an X chromosome, the offspring will be _____. |
| | A) | female, XO |
| | B) | female, XXX |
| | C) | male, OY |
| | D) | male, XXY |
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| 68 | |
Individuals with Down syndrome have three copies of _____. |
| | A) | the X chromosome |
| | B) | chromosome 13 |
| | C) | chromosome 21 |
| | D) | the Y chromosome |
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| 69 | |
Which of the following symptoms of Down syndrome may be associated with the Gart gene? |
| | A) | leukemia |
| | B) | mental retardation |
| | C) | accelerated rate of aging |
| | D) | cataracts |
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| 70 | |
Turner females, XO, are characterized by _____. |
| | A) | normal breast development |
| | B) | regular menstrual cycles |
| | C) | infertility |
| | D) | none of the above |
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| 71 | |
Triplo-X (XXX) individuals are especially feminine. |
| | A) | True |
| | B) | False |
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| 72 | |
When fragile X chromosomes occur in females the symptoms tend to be less severe than those in males with fragile X. |
| | A) | True |
| | B) | False |
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| 73 | |
Klinefelter males are characterized by _____. |
| | A) | two Y chromosomes |
| | B) | underdeveloped testes and prostate glands |
| | C) | normal size hands and feet |
| | D) | all of the above |
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| 74 | |
Fragile X syndrome is characterized by _____. |
| | A) | autism |
| | B) | delayed speech development |
| | C) | hyperactivity |
| | D) | all of the above |
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| 75 | |
Jacob syndrome (XYY) is caused by nondisjuction that occurred during _____. |
| | A) | meiosis I |
| | B) | meiosis II |
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| 76 | |
When Down syndrome tends to run in the family of the father or mother the cause is _____. |
| | A) | the advanced age of the mother |
| | B) | a translocation between chromosomes 14 and 21 |
| | C) | a deletion from chromosome 21 |
| | D) | duplication of chromosome 18 |
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| 77 | |
A _____ is characterized by only one of a particular kind of chromosome instead of a pair. |
| | A) | monosomy |
| | B) | disomy |
| | C) | trisomy |
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| 78 | |
Fragile X syndrome is characterized by _____. |
| | A) | an extra X chromosome |
| | B) | over 230 copies of the base triplet CGG in the fragile X chromosome |
| | C) | the absence of a Y chromosome |
| | D) | a normal phenotype |
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| 79 | |
Contrary to what occurs with other mutant alleles on the X chromosome, a male can be a carrier for fragile X syndrome. |
| | A) | True |
| | B) | False |
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| 80 | |
Although both males and females receive the premutation (50-230 copies of the repeat) for fragile X, only the females pass on the full mutation (over 230 copies of the repeat). |
| | A) | True |
| | B) | False |
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| 81 | |
Which is an X-linked recessive disorder? |
| | A) | color blindness |
| | B) | hemophilia |
| | C) | muscular dystrophy |
| | D) | all of the above |
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| 82 | |
The alleles of most sex-linked genetic disorders are on the _____ chromosome. |
| | A) | X |
| | B) | Y |
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| 83 | |
X-linked conditions can be dominant or recessive, but most known are dominant. |
| | A) | True |
| | B) | False |
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| 84 | |
Which of the following is typical of X-linked recessive conditions? |
| | A) | more males than females are affected |
| | B) | females can be carriers |
| | C) | all the sons of a female who has the condition will have the condition |
| | D) | all of the above |
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| 85 | |
The daughters of a man who is color blind and a woman who is homozygous dominant will _____. |
| | A) | be carriers |
| | B) | be color blind |
| | C) | have normal vision |
| | D) | both A and C |
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| 86 | |
If a condition is X-linked recessive condition females must be homozygous recessive to display the condition. |
| | A) | True |
| | B) | False |
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| 87 | |
Which of the following is on the X chromosome? |
| | A) | the gene for red-sensitive protein |
| | B) | the gene for A-antigen on red blood cells |
| | C) | the gene for the enzyme that breaks down phenylalanine |
| | D) | the gene for the enzyme hexosaminidase |
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| 88 | |
Which of the following is characteristic of Duchenne muscular dystrophy? |
| | A) | toe walking |
| | B) | passage of the recessive allele from carrier mother to carrier daughter |
| | C) | an absence of a protein called dystrophin |
| | D) | all of the above |
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| 89 | |
Since males have only one X chromosome, X-linked recessive disorders are always expressed in males. |
| | A) | True |
| | B) | False |
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| 90 | |
Queen Victoria was a carrier for hemophilia so her sons had a _____ chance of inheriting the disease. |
| | A) | 25% |
| | B) | 50% |
| | C) | 75% |
| | D) | 100% |
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| 91 | |
The present British royal family does not have any hemophiliacs because Victoria's oldest son, King Edward VII, did not receive the gene and therefore could not pass it on to any of his descendents. |
| | A) | True |
| | B) | False |
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| 92 | |
Certain traits common in males, like pattern baldness, are controlled by autosomal alleles which are influenced by the sex hormones. |
| | A) | True |
| | B) | False |
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| 93 | |
Which of the following is true of hemophilia? |
| | A) | there is only one type of hemophilia |
| | B) | the affected people only bleed externally after an injury |
| | C) | more females than males are affected |
| | D) | the genetic engineering product, factor VIII, can be used to treat hemophilia B |
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