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

Gene causing sickle-celled anaemia is located on

  1. X-chromosome

  2. Y-chromosome

  3. Autosome

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

 Sickle-celled anaemia is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Multiple choice

Which of the following genes have lethal effect?

  1. Gene controlling the production of hemoglobin

  2. Defective gene causing haemophilia

  3. Dominant allele of gene controlling fur colour in mice in homozygous state

  4. Recessive allele of gene causing sickle-celled anaemia in heterozygous state
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

 Recessive allele of gene causing sickle-celled anaemia in heterozygous state have lethal effects.

Multiple choice

Klinfelter’s syndrome is due to

  1. mutation of gene on sex chromosome

  2. trisomy of specific autosome

  3. non-disjunction of sex chromosome during oogenesis

  4. deletion of segment in x-chromosome
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

 Klinfelter’s syndrome is due to non-disjunction of sex chromosome during oogenesis,also known as 47,XXY or XXY.

Multiple choice

Which of the following is called favism?

  1. Glucose6-phosphatedehydrogenase deficiency syndrome

  2. Sickle cell anaemia

  3. Alkaptonuria

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

Favism is a hemolytic condition triggered by eating fava beans, occurring in people with Glucose-6-phosphate dehydrogenase (G6PD) deficiency. G6PD is an enzyme crucial for maintaining red blood cell membrane integrity; its deficiency makes RBCs susceptible to oxidative damage from compounds in fava beans. Sickle cell anaemia (B) is a hemoglobin disorder, Alkaptonuria (C) is a metabolic disorder affecting tyrosine metabolism, and Mongolism (D) is an outdated term for Down syndrome (trisomy 21).

Multiple choice

In a married couple, an unaffected woman carries one copy of a gene mutation for an X-linked recessive disorder. She has an affected son, an unaffected daughter who carries one copy of the mutation. Which among the following X-linked recessive disorders are caused by a mutation of the Factor VIII gene in human beings?

  1. Red-green colour blindness

  2. Hemophilia A

  3. Hemophilia B

  4. X-linked agammaglobulinemia

  5. X-linked ichthyosis
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Hemophilia A is a blood clotting disorder caused by the mutation of factor VIII gene and leads to the deficiency of factor VIII. It was once thought to be the royal disease found in the descendants of Queen Victoria.

Multiple choice

Obesity genetics has been predominantly driven by research into monogenic or syndromic obesity. Which of the following statements does NOT characterise monogenic obesity?

  1. The receptor gene mutations might be one of the reasons for severe obesity.

  2. In Leptin melanocortin pathway, leptin crosses the blood brain barrier and triggers the neurons present in the hypothalamus to generate peptides.

  3. The phenotype is directly and strongly related to the genotype.

  4. The common monogenic obesity disorder was represented by excess of MC4R .

  5. It occurs due to the congenital leptin deficiency.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The mutation in the melanocortin-4 receptor protein (MC4R) which is a component of leptin-melanocortin pathway was detected to be related to obesity. The common monogenic obesity disorder was represented by MC4R deficiency. The obesity was accounted due to homozygous and heterozygous mutations in MC4R.

Multiple choice

Which of the following genetic disorders is monosomic?

  1. Dermoid tumors of the ovary

  2. Turner syndrome

  3. Hydatidiform mole

  4. Klinefelter syndrome

  5. Fragile X syndrome
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A monosomic disorder results when a chromosome pair fails to separate during either meiosis 1 or 2, a process known as nondisjunction. Nondisjunction can result in monosomy or trisomy. Turner syndrome occurs when part or all of the second sex chromosome is absent, resulting in a 45X karyotype.

Multiple choice

A dominantly inherited trait affects a newborn baby of Verma family and his grandmother, but neither parent. Which of the following principles does it illustrate?

  1. Variable expressivity

  2. Somatic mosaicism

  3. Germline mosaicism

  4. Non-penetrance

  5. Somatic mutations
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Non-penetrance means that a person has inherited the genetic change, but that it does not manifest the associated phenotype. A skipped generation for a dominant trait is an example of non-penetrance.

Multiple choice

A pregnant woman is known to be at risk for autosomal dominant polycystic kidney disease and requests a genetic test to determine if she has inherited the mutation from his affected mother. At the time of testing, she is asymptomatic, but the condition displays age-dependent penetrance. Which of the following types of genetic testing method illustrate the woman's condition?

  1. Pharmacogenetic testing

  2. Predisposition testing

  3. Presymptomatic testing

  4. Diagnostic testing

  5. Predictive testing
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Presymptomatic testing involves determining whether an individual has inherited a gene mutation that exhibits age-dependent penetrance.

Multiple choice

The doctor told a couple that their new born baby is suffering from a metabolic disorder caused by a mutation in the DHCR7 gene on chromosome 11. Which of the following disorders could the doctor be referring to?

  1. Smith-Lemli-Opitz syndrome

  2. Severe Combined Immunodeficiency

  3. Sickle cell anaemia

  4. Neurofibromatosis type 1

  5. Phenylketonuria
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

SLOS Chromosome SLOS is a metabolic disorder caused by a mutation in the DHCR7 (7-dehydrocholesterol reductase) gene on chromosome 11. This gene codes for an enzyme that is involved in the production of cholesterol. People who have SLOS are unable to produce enough cholesterol to support normal growth and development.