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 zoology why do we fall ill health introduction to health health and its maintenance

Which one of the following is a genetic disease?

  1. Scurvy

  2. Leukemia

  3. Goitre

  4. Haemophilia
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
In Haemophilia, the blood fails to clot when exposed to air and even a small skin injury results in continuous bleeding and can lead to death from loss of blood.
Haemophilia is a well-known disorder which is a sex-linked recessive condition. The recessive X-linked gene for haemophilia shows characteristic Criss cross inheritance. A single recessive gene in man results in haemophilia whereas a woman needs two sets of genes for the same.
Hence, the correct answer is 'Haemophilia'


Multiple choice zoology why do we fall ill health introduction to health health and its maintenance

The absence of anti-haemophilic globulin or factor VIII causes 

  1. Haemophilia A

  2. Haemophilia B

  3. Colour blindness

  4. Sickle cell anaemia
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Haemophilia A is a genetic deficiency in clotting factor VIII which causes increased bleeding and usually affects males. It is the X-linked recessive trait. 

Therefore, the correct answer is option A.

Multiple choice zoology why do we fall ill health introduction to health health and its maintenance

 A male hemophiliac, marries a normal woman, and they have four normal children, two boys (Mark and Mike) and two girls (Molly and Mary). Mark, Mike, Molly, and Mary all marry normal individuals and have children. The children (male and female) of Mark's or Mike's children were normal but the sons of Molly and Mary all display symptoms of hemophilia while their daughters do not.
Which of the following statement best explains the reason that Mark, Mike, Molly, and Mary do not display symptoms of hemophilia, even though their father, John, is a hemophiliac?

  1. Hemophilia is an X-linked disorder, and John can pass on only his Y chromosome.

  2. Hemophilia is an X-linked disorder and even though Molly and Mary received a hemophiliac X chromosome from father, mother gave them a normal X chromosome.

  3. Hemophilia is a Y-linked disorder and therefore cannot be displayed in females.

  4. Hemophilia is a Y-linked disorder and Mark and Mike must have received an X chromosome from John.

  5. Hemophilia is an X-linked disorder, and even though Mark and Mike received a hemophiliac X chromosome from John, Jane gave them a normal X chromosome.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Out of this family, the only members that express this condition are males. This is a tip-off for X-linked disorders, which are more common in males because they have only a single X chromosome.
John’s genotype is X$^h$Y. He passed his Y chromosome to Mark and Mike; they also received a normal X from Jane, thus they do not have hemophilia, nor can they pass it on to their kids. Molly and Mary received X$^h$ from John but also received a normal X from Jane, thus they are carriers of hemophilia but do not display its symptoms.

Therefore, the correct answer is option B.

Multiple choice biology blood circulatory system of human cardiac disorders cardiac regulation and disorders the blood system

Which disease occurs due to Rh incompatibility?

  1. Sickle cell anaemia

  2. Thalassemia

  3. Erythroblastosis foetalis

  4. Haemophilia
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

. If an Rh-positive man marries an Rh-negative woman, then the first foetus (and foetuses thereafter) will be Rh-positive. In this case, the Rh-positive antigen from the foetus will enter into the bloodstream of the mother and there will be the formation of anti-Rh antibodies in mother’s body. During her second pregnancy, these antibodies will attach the red blood cells of the Rh-positive foetus and coagulate the blood, resulting in severe complications. These complications arising due to Rh incompatibility are called erythroblastosis foetalis.

So, the correct answer is 'Erythroblastosis foetalis'.

Multiple choice biology blood circulatory system of human cardiac disorders cardiac regulation and disorders the blood system

Which disorder is due to gene incompatibility?

  1. Erythroblastosis fetalis

  2. Jaundice

  3. Hemolytic disease of new born

  4. Both A and C
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Erythroblastosis fetalis is a hemolytic anemia in the fetus caused by the transplacental transmission of maternal antibodies to the fetal RBCs. In this alloimmune condition that develops in the fetus, the IgG molecules produced by the mother pass through the placenta and so is because of incompatibility.
Jaundice is caused because of the excess of bilirubin in the blood.
Therefore, the correct answer is option D.

Multiple choice biology blood circulatory system of human cardiac disorders cardiac regulation and disorders the blood system

The disease as a result of prolonged clotting time is due to the lack of plasma thromboplastin component (PTC) necessary to the formation of thromboplastin, is

  1. Christmas disease

  2. Hypoprothrombinemia

  3. Haemophilia

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

The Christmas disease is nothing but the Haemophilia B. It is a blood clotting disorder caused by a mutation of the factor IX gene, leading to a deficiency of factor IX . It is called as Christmas disease, as it is named after Stephen Christmas, the first patient described with this disease.
Therefore, the correct answer is option A.

Multiple choice biology blood circulatory system of human cardiac disorders cardiac regulation and disorders the blood system

Hereditary disease condition in which the blood fails to coagulate

  1. Sickle cell anaemia

  2. Leukemia

  3. Haemophilia

  4. Alkaptonuria
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Haemophilia is a group of hereditary disease, that impair the body's ability to control blood clotting or coagulation.
Thus, the correct answer is option (C), 'Haemophilia'.

Multiple choice biology blood circulatory system of human cardiac disorders cardiac regulation and disorders the blood system

The incorrect statement with regard to haemophilia is

  1. It is a recessive disease.

  2. It is a dominant disease.

  3. A single protein involved in the clotting in blood is affected.

  4. It is sex-linked disease.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Haemophilia is a group of hereditary genetic disorders that impair the body's ability to control blood clotting, which is used to stop bleeding when a blood vessel is broken.
It is recessive (not dominant) sex-linked, X-chromosome disorder.
Thus, the correct answer is option (B), 'It is a dominant disease'.

Multiple choice biology blood circulatory system of human cardiac disorders cardiac regulation and disorders the blood system

The disease erythroblastosis fetalis in human embryo is caused due to:

  1. Disadjustment of blood groups

  2. Disadjustment of Rh factor

  3. Both A and B

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Erythroblastosis fetalis is hemolytic anemia in the fetus caused by transplacental transmission of maternal antibodies to the fetal RBCs. The disorder usually results from incompatibility between the maternal and fetal blood groups, often Rh antigens. Erythroblastosis fetalis classically results from Rh incompatibility, which may develop when a woman with Rh-negative blood is impregnated by a man with Rh-positive blood and conceives a fetus with Rh-positive blood.
Thus, the correct answer is option (B), 'Disadjustment of Rh factor'.

Multiple choice zoology immunity and blood groups compatibility of blood groups blood group blood groups and compatibility advance

Biological marriage of one of the following should be avoided
                                                 or

After examining the blood groups of a couple, the doctor advised them not to have more than one child. The blood group of the couple are likely to be

                                                or

In which of the following situations, is there a risk factor for children of incurring erythroblastosis foetalis

  1. Rh+ male and Rh- female

  2. Rh+ male and Rh+ female

  3. Rh- male and Rh+ female

  4. Rh- male and Rh- female
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Erythroblastosis foetalis occurs when an Rh-negative mother carries an Rh-positive fetus, leading to the production of anti-Rh antibodies.

Multiple choice zoology immunity and blood groups compatibility of blood groups blood group blood groups and compatibility advance

Name of the disease due to Rh factor.

  1. Accquired Immuno Deficiency Syndrome

  2. Turner's Syndrome

  3. Erythroblastosis foetalis

  4. Sickle - cell anaemia
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When a woman is pregnant having Rh negative blood group and the blood group of the foetus is Rh positive, then her baby's blood type will be incompatible with her own. This can cause a condition known as erythroblastosis fetalis, where the mother's red blood cells attack those of the baby as there would any foreign invaders. Rh incompatibility and ABO incompatibility are the two main cause. Both are associated with blood type. Thus, the correct answer is option C.

Multiple choice zoology body fluids and circulation compatibility of blood groups blood group blood groups and compatibility advance

Rh factor may be responsible for

  1. Turner's syndrome

  2. Accquired Immuno Deficiency Syndrome

  3. Sickle cell anaemia

  4. Erythroblastosis foetalis
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Erythroblastosis foetalis is a disease of the new born which is caused by Rh incompatibilty. This happens when mother is Rh negative and the child she is bearing is Rh positive. Thus the Rh antigen of child can trigger the antibodies inside mother which can travel through circulation thus destroying foetus blood cells. Thus, correct answer is option D.

Multiple choice biology the age of adolescence menstruation in females changes at puberty what happens if an egg is not fertilized?

The cause of Cat-cry syndrome is due to

  1. Loss of a segment of X-chromosome

  2. Loss of a segment of 5"' chromosome

  3. Loss of segment of Y-chromosome

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cat-cry or cri-due chat syndrome is caused by the deletion of short arm of chromosome number 5 (5p). So, the genotype of affected individual in 46, XX, Sp- in female and 46, XX, 5p in males.

Multiple choice evs science of kitchen balanced diet and malnutrition assimilation of food components and importance of food skeletal system and muscles assimilation of food and egestion busy at work - our internal organs

Haemolytic jaundice is caused by a dominant gene but only 10% of the people actually develop it. What proportion of the children would be expected to develop the disease, if a heterozygous man marries a homozygous normal woman?

  1. 1/5

  2. 1/10

  3. 1/15

  4. 1/20
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Genotype of the man --> A$^H$A (where A$^H$ is the chromosome carrying dominant gene for haemolytic jaundice and A is the homologous chromosome carrying the normal allele).
Genotype of woman --> AA
P generation :          A$^H$A    X     AA


F$ _1$ generation :     A$^H$A   A$^H$A   AA    AA
                          (Diseased:Normal) = (1:1)
Only 10% of the people having diseased genotype actually suffer from haemolytic jaundice, this turns the ratio to (0.1:1).
Thus, proportion of children expected to develop the disease for the given cross= 0.1/2 (0.1 children are affected out of two children) = 1/20