Biology

Human Genetics and Disorders

882 Questions

Human Genetics and Disorders covers the inheritance patterns, genetic mutations, and molecular basis of hereditary diseases. Topics include sex-linked traits, cancer genetics, and metabolic disorders. This section tests knowledge critical for biology exams and general science papers.

Genetic mutationsInherited disordersCancer geneticsGenetic testingMendelian inheritance

Human Genetics and Disorders Questions

Multiple choice

Which type of mutation would not be expected to be detected in a molecular diagnostic test that is based on sequencing each exon of a gene in genomic DNA from a male suspected of having an X-linked disorder?

  1. Missense mutation

  2. Nonsense mutation

  3. Deletion of an exon

  4. Inversion of part of the gene
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Yes, the inversion of part of gene cannot be detected . As it would not cause the exons to be absent or missing, and the sequencing reaction would not reveal that the exons are no longer arranged in the proper order on genomic DNA.

 

Multiple choice

What are Amsterdam criteria used to assess?

  1. Risk of hereditary nonpolyposis colon cancer.

  2. Risk of familial adenomatosis polyposis.

  3. Risk of hereditary breast and ovarian cancer.

  4. Risk of Cowden syndrome.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Yes, it is the correct answer. The Amsterdam criteria are used to assess risk of HNPCC to guide identification of individuals for whom genetic testing may be helpful.

Multiple choice

Angelman syndrome is a severe form of mental retardation which depends upon the gender of the parent from whom they are inherited. This unusual kind of inheritance pattern is known as

  1. modifying gene

  2. genome imprinting

  3. incomplete penetrant

  4. intermediate expression
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When genes have a different effect depending on the gender of the parent from whom they are inherited, it is referred to as genome imprinting. Diabetes, psoriasis, and Prader-Willi syndrome are other examples of this phenomenon.

Multiple choice

In a family, having a history of genetic disorders, knowing the sex of a foetus can be important because

  1. sons will be more prone to autosomal defects

  2. daughters will be more prone to autosomal defects

  3. both son & daughter will be equally affected

  4. There will be more chances that sons will bear X-linked traits expressed in their phenotype.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

There is a far greater probability of males expressing recessive alleles in their phenotypes if they are carried on X chromosomes. For females to have such traits, they would have to inherit the recessive allele for them on both of their X chromosomes.

Multiple choice

Which among the following chromosomal abnormalities causes male to have feminine body contours with bigger breasts; small penis and prostate gland with relatively little body hair and impotency?

  1. Klinefelter's syndrome

  2. XYY syndrome

  3. Richard Speck Syndrome

  4. Achard syndrome
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The feminising effects of Klinefelter syndrome can be diminished if boys are treated regularly with testosterone injections from the age of puberty. As a result of this treatment, most become sufficiently ordinary in appearance to live in society without notice.

Multiple choice

A recessive allele p is responsible for a condition called hypertonia. In a couple, male has this condition. One of their four children also has this condition. Suggest the possible genotypes of the man and woman.

  1. Father is Pp and mother is PP.

  2. Father is pp and mother is PP.

  3. Both parents are pp.

  4. Father is pp and mother is Pp
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This is the only option that fits the criteria in the question. Since father is hypertonic so he must be pp & mother is carrier so she must be Pp.

Multiple choice

The severe medical problem associated with the Rh blood group is

  1. transfusion incompatibility

  2. chronic anemia for Rh negative persons

  3. Chronic anemia for Rh positive persons

  4. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The most life threatening problem is the result of Rh blood type incompatibility between a mother and her developing fetus.

Multiple choice

The genetic disorder sickle-cell anemia signifies

  1. mutation

  2. pleiotropy

  3. epistasis

  4. heterozygous dominance
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The sickle cell is an example of a mutation that is beneficial when maintained in heterozygotes. When you are homozygous for the trait you get sickle cell anemia. When a person is heterozygous for the sickle cell gene they have some added protection from malaria.