1.
In genetics a "wild" type is
Correct Answer
A. The pHenotype most commonly found in nature
Explanation
The term "wild" type in genetics refers to the phenotype that is most commonly observed in nature. This means that it is the most prevalent or common form of a trait or characteristic within a particular population or species. It is important to note that the wild type does not necessarily indicate dominance or recessiveness, as it is simply a term used to describe the most commonly occurring phenotype.
2.
The genetic event that results in Turner's syndrome (XO) is probably
Correct Answer
A. Nondisjunction
Explanation
Turner's syndrome (XO) is a genetic disorder that occurs in females when one of the two X chromosomes is missing or incomplete. This genetic event is most likely caused by nondisjunction, which is the failure of chromosomes to separate correctly during cell division. Nondisjunction can result in the formation of gametes with an abnormal number of chromosomes, leading to genetic disorders such as Turner's syndrome. Deletion, parental imprinting, monoploidy, and independent assortment do not directly result in Turner's syndrome.
3.
A 1:1:1:1 ratio of offspring from a dihybrid test cross indicates that
Correct Answer
E. The genes are not linked
Explanation
A 1:1:1:1 ratio of offspring from a dihybrid test cross indicates that the genes are not linked. This is because in a test cross, one parent is homozygous recessive for both traits, and the other parent is heterozygous for both traits. If the genes were linked, there would be a deviation from the expected 1:1:1:1 ratio due to the crossing over of linked genes during meiosis. However, since the ratio is 1:1:1:1, it suggests that the genes are independently assorting and are not linked.
4.
A color blind son inherited this trait from his
Correct Answer
A. Mother
Explanation
A color-blind son typically inherits this trait from his mother. The genes responsible for color vision are located on the X chromosome, and males inherit one X chromosome from their mother. If the mother carries the gene for color blindness (even if she is not color-blind herself) and passes it to her son, he may be color-blind.
5.
The chromosomal theory of inheritance states
Correct Answer
E. All of the above
Explanation
The chromosomal theory of inheritance states that genes are located on chromosomes, chromosomes segregate during meiosis, and chromosomes undergo independent assortment during gamete formation. Mendel's Laws of Inheritance relate to the behavior of chromosomes in meiosis. Therefore, the correct answer is "all of the above" because all of these statements are true according to the chromosomal theory of inheritance.
6.
Down's syndrome is a trisomy of chromosome number
Correct Answer
D. 21
Explanation
Down's syndrome is a genetic disorder caused by the presence of an extra copy of chromosome 21. This condition is also known as trisomy 21. Individuals with Down's syndrome typically have characteristic physical features, intellectual disabilities, and may also have certain health issues. The presence of an extra chromosome 21 disrupts normal development and leads to the symptoms associated with Down's syndrome.
7.
Cri du chat syndrome is caused by a(n)___________on chromosome 5.
Correct Answer
A. Deletion
Explanation
Cri du chat syndrome is caused by a deletion on chromosome 5. This means that a portion of chromosome 5 is missing or deleted, leading to the characteristic features and symptoms of the syndrome. The deletion can occur during the formation of reproductive cells or early in embryonic development. This genetic abnormality disrupts the normal development and function of various body systems, resulting in the specific physical and intellectual disabilities associated with Cri du chat syndrome.
8.
Males with an extra Y chromosome
Correct Answer
B. Do not exhibit any well defined syndrome
Explanation
Males with an extra Y chromosome do not exhibit any well-defined syndrome. This means that they do not show any specific set of symptoms or characteristics that are associated with having an extra Y chromosome. While individuals with certain genetic conditions may exhibit distinct syndromes, such as Down syndrome or Turner syndrome, males with an extra Y chromosome do not have a recognized syndrome associated with their genetic makeup.
9.
A child with a chromosomal deletion on chromosome 15 will exhibit Angelman's syndrome if it came from his
Correct Answer
A. Mother
Explanation
A child with a chromosomal deletion on chromosome 15 will exhibit Angelman's syndrome if it came from his mother. This is because Angelman's syndrome is caused by the absence or mutation of genes on the maternal copy of chromosome 15. The paternal copy of chromosome 15 does not contribute to the development of Angelman's syndrome. Therefore, if the child inherits the chromosomal deletion from his mother, he will exhibit the syndrome.
10.
A child with a chromosomal deletion on chromosome 15 will exhibit Prader Willi syndrome if the it came from his
Correct Answer
B. Father
Explanation
Prader-Willi syndrome is caused by the absence of genetic material on the paternal chromosome 15. This means that if a child has a chromosomal deletion on chromosome 15, specifically from the father's side, they are more likely to exhibit Prader-Willi syndrome. The genetic material from the mother's side is not typically affected in this syndrome.