Biology

Human Genetics and Disorders

844 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 of the following are XY-linked hereditary disorders?

  1. Colour blindness
  2. Hypertrichosis
  3. Haemophilia
  4. Retinitis pigmentosa
  5. Total colour blindness

  1. 1 and 2

  2. 2 and 3

  3. 3 and 4

  4. 4 and 5

  5. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Retinitis pigmentosa is XY-linked hereditary, degenerative eye disease that causes severe vision impairment and often blindness. Total color blindness is severe vision imparement leaving a person completely unable to distinguish any color. It is a XY-linked hereditary disease.

Multiple choice

Which of the following are examples of autosomal recessive hereditary disorders? P. Albinism Q. Phenylketonuria R. Achondroplasia S. Brochydatyly

  1. P and Q

  2. P and R

  3. Q and R

  4. Q and S

  5. R and S
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Albinism and Phenylketonuria are examples of autosomal recessive hereditary disorders.Albinism is caused due to inability to produce melanin pigment characterized by absence of normal colouration of skin.Phenylketonuria is a metabolic disorder which arises due to deficiency of an enzyme phenylalanine hydroxylase,  which converts phenylalanine to tyrosine.

Multiple choice

Which of the following statements is/are correct?

a. Congenital diseases occur due to genetic disorders. b. Allergies are caused by external substances such as dust, pollen food etc. c. Degenerative diseases are caused by the infections caused by external substances.

  1. a, b and c

  2. a and b

  3. a and c

  4. b and c

  5. b only

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is the correct answer as both statements are correct. Congenital diseases occur due to genetic disorders. Allergies are caused by external substances such as dust, pollen food etc.

Multiple choice

Myasthenia gravis in the neonate is usually an autoimmune disorder is and is thought to be caused by

  1. an inherited genetic defect

  2. transplacental transfer of maternal IgG against the TSH receptor

  3. anti-idiotype to maternal IgG

  4. transplacental transfer of maternal IgG against the acetylcholine receptor

  5. maternal T-cells transferred across the placenta
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Transient neonatal autoimmune diseases are seen due to the transplacental transfer of maternal IgG autoantibodies in those diseases in which IgG is the effector component of the autoimmune response. The disease will be of the same type as seen in the mother because the autoantibodies will determine the target organ specificity. The neonatal disease resolves after a few weeks as the maternal IgG is catabolised.

Multiple choice

Splicing is a post transcriptional modification in which newly transcribed hetero nuclear RNA is modified into mRNA. Faulty splicing can cause diseases in any organism. Identify the way by which faulty splicing can cause thalasemia in humans.

  1. Malformation of α chain of haemoglobin leads to α thalassemia.

  2. Malformation of β chain of haemoglobin leads to β thalassemia.

  3. Malformation of one α and one β chains of haemoglobin causes α β major thalassemia.

  4. Malformation of both α and β chains of haemoglobin causes α β major thalassemia.

  5. α chains have less amino acids.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is due to the mutation that results in a nucleotide change at an exon-intron junction, which leads to lack of synthesis of β chain of haemoglobin and consequently the disease β thalassemia occurs to the human being.

Multiple choice

Multiple coding sequences are inserted in between the genes encoding for MHC-I and MHC-II. The insertions are genetically engineered so as to prevent any loss of function in individual genes. Such a model is then implemented in the biological offspring of a couple. Unfortunately, the child is born with rudimentary kidneys. A kidney transplant is required and doctors look for an advent match. Based on the above data, answer the following question. The doctors should look for matches in

  1. blood relatives to increase the chances

  2. outside blood relatives as the MHC expression will be different

  3. brothers and sisters because they would have got the exact tissue typing match

  4. parents, as they will be the best possible match in this condition
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When MHC genes are engineered to be different from both parents, blood relatives won't have matching MHC profiles. The genetic modifications create unique MHC combinations not present in the family. Therefore, doctors should look among non-relatives where the MHC might coincidentally match. Siblings and parents would NOT match because their natural MHC differs from the engineered genes.

Multiple choice

In which of the following syndromes is gynaecomastia the typical feature?

  1. Cystic fibrosis

  2. Klinefelter’s syndrome

  3. Down’s syndrome

  4. Autism

  5. Turner’s syndrome
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Klinefelter’s syndrome is a genetic disease of males where cells contain an additional X chromosome, resulting in tall, thin anatomy and small unfertile testes. Gynaecomastia is the typical feature.