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 evs we are special defects of eye disorders of nervous system braille script

Which of the following disorder is not hereditary?

  1. Haemophilia

  2. Cataract

  3. Sickle cell anaemia

  4. Colour blindness
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
A. Haemophilia is a X-linked recessive genetic disorder that occurs due to deficiency of clotting factors in the blood and therefore, there is no formation of clot at the site of wound. 
B. Cataract is an eye disease that occurs in older people. The visibility is reduced because the eye lens becomes opaque. It is treated by surgery.
C. Sickle cell anaemia is a autosomal recessive genetic disorder in which red blood cells become sickle shaped and this causes oxygen tension in the body.
D. Colour blindness is a X-linked genetic disorder in which there is inability to distinguish colours due to defect in cones (photoreceptor cells associated with daylight vision and colour vision).
Hence, cataract is not hereditary because it is not a genetic disorder.
So, the correct answer is 'Cataract'.
Multiple choice evs we are special defects of eye disorders of nervous system braille script

Which one of the following diseases in man belongs to the same category as haemophilia?

  1. Hypermetropia

  2. Rabies

  3. Night blindness

  4. Colour blindness
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Colour blindness and haemophilia are both X-linked recessive disorders. 

Red-green colour blindness, a very common trait in humans affects between 7% and 10% of men and 0.49% to 1% of women. 
Hemophilia A, a blood clotting disorder is caused by a mutation of the factor VIII gene and hemophilia B, also known as 'Christmas disease', is a blood clotting disorder, caused by a mutation of the factor IX gene. 

Multiple choice biology soldiers of defense blood clotting and healing of wounds coagulation of blood blood clotting

Haemophilia is a condition where there is 

  1. A failure in the clotting mechanism of blood

  2. A delay in the clotting of blood

  3. No production of haemoglobin in the blood

  4. No production of melanin in the skin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • Haemophilia is a group of hereditary genetic disorders in which the body's blood clotting ability fails to stop bleeding if any cut happens.
  • Thus, it is also known as bleeder's disease. One type of haemophilia called haemophilia A happens due to the deficiency of blood clotting factor VIII. 
Therefore, the correct answer is option A.

Multiple choice

Hemophilia is a sex-linked trait.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hemophilia is a classic example of an X-linked recessive trait, meaning the gene responsible is located on the X chromosome.

Multiple choice

Can sickle cell anemia be passed down if only one parent possesses the gene?

  1. Yes

  2. No

  3. It depends on the gender of the parent and offspring
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sickle cell anemia is an autosomal recessive disorder. A person must inherit two copies of the mutated gene (one from each parent) to have the disease; if only one parent possesses the gene, the offspring can be a carrier but will not have the disease.

Multiple choice

Phenylketonuria is caused by a defect in the gene for an enzyme that converts:

  1. Tyrosine to phenylalanine causing a buildup of phenylalanine

  2. Phenylalanine to tyrosine causing a buildup of phenylalanine

  3. Phenylalanine to tyrosine causing a buildup of tyrosine

  4. Tyrosine to phenylalanine causing a buildup of tyrosine
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

PKU is caused by a deficiency of the enzyme phenylalanine hydroxylase. This enzyme is responsible for converting the amino acid phenylalanine into tyrosine.

Multiple choice

In which genetic disorder blood may not coagulate?

  1. Haemophilia

  2. Anemia

  3. Colour blindness

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

Haemophilia is an inherited genetic disorder that impairs the body's ability to make blood clots, a process needed to stop bleeding. Anemia involves a lack of healthy red blood cells, while thalassemia affects hemoglobin production, and color blindness affects vision.

Multiple choice

The deletion of the POMC gene in Retrievers means?

  1. Decrease in Adiposity (Weight gain)

  2. Increase in Adiposity (Weight gain)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The pro-opiomelanocortin (POMC) gene deletion, which is common in Labrador Retrievers and Flat-Coated Retrievers, disrupts the neural pathways that signal satiety. This genetic mutation leads to increased food-seeking behavior, a higher appetite, and a significant predisposition to increased adiposity and weight gain.

Multiple choice

Which of the terms is LEAST related to the others

  1. fragile X syndrome

  2. X inactivation

  3. tortoise-shell coat pattern in cats

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

X inactivation, tortoise-shell coat patterns, and Barr bodies are all phenomena related to the dosage compensation mechanism in mammals. Fragile X syndrome is a genetic disorder caused by a mutation in the FMR1 gene, which is distinct from the regulatory mechanism of X inactivation.

Multiple choice

Choose the statement that correctly describes genomic imprinting?

  1. gender of parent you inherit an allele from affects trait

  2. greater in females because larger contribution of cytoplasm

  3. may explain Duchenne's muscular dystrophy

  4. explains sex-linked inheritance
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Genomic imprinting is an epigenetic phenomenon where the expression of a gene depends on whether it was inherited from the mother or the father.