NEET · Biology —

Principles of Inheritance and Variation appeared 7 times across 1 year — 7.8% of Biology. This question is from Genetic Disorders.

Year 2024 Total
Questions 7 7
Practice all Principles of Inheritance and Variation questions → View full NEET weightage & trends →

Which one of the following disorders is caused by the substitution of Glutamic acid (Glu) by Valine (Val) at the sixth position of the beta globin chain of the haemoglobin molecule?

Solution & Explanation

Related Formula

Sickle Cell Anaemia: Single point mutation at 6th codon of β-globin gene (GAG arrow GUG), replacing Glutamic acid (Glu) with Valine (Val).

Core Logic

Sickle-cell anaemia is an autosomal recessive genetic defect caused by point mutation resulting in Glu arrow Val substitution at 6th position of β-globin polypeptide chain, leading to RBC polymerisation under low oxygen tension.

Step 1: Conclusion

The disorder is Sickle-cell anaemia. Option (3) is correct.

Pattern Recognition

Glu to Val at 6th position of β-globin = Sickle-cell anaemia.

Chapter Mix

Class 12 Biology: Principles of Inheritance and Variation

Reference Study Guides

Principles Of Inheritance And Variation

More Principles of Inheritance and Variation Previous-Year Questions — Page 2

Q154 neet_2024_05_may_morning Sex Determination in Grasshopper (XX-XO Type)
In a population of a grasshopper species, the chromosome number of some members is 23 and some other members possess 24 chromosomes. The 23 and 24 chromosome-bearing members in this species are:
  • A. all males
  • B. all females
  • C. females and males, respectively
  • D. males and females, respectively

Solution

Related Formula

Grasshopper Sex Determination (XX-XO): aligned Male &= 22 Autosomes + X = 23 chromosomes (XO) Female &= 22 Autosomes + XX = 24 chromosomes (XX) aligned

Core Logic

In grasshoppers, sex determination is of the XX-XO type. Males have only one X chromosome in addition to autosomes (XO), giving them an odd total chromosome number (23). Females have a pair of X chromosomes (XX), giving them an even total chromosome number (24).

Step 1: Match

23 chromosomes = males; 24 chromosomes = females.

Pattern Recognition

Sees: "grasshopper 23 and 24 chromosomes". Shortcut: XX-XO type arrow XO male has 1 less chromosome (23) than XX female (24).

Chapter Mix

Class 12 Biology: Principles of Inheritance and Variation

Q159 neet_2024_05_may_morning Gametogenesis in Haploid Organisms
In which animal do haploid cells divide mitotically to produce gametes?
  • A. Male honeybees
  • B. Male grasshoppers
  • C. Male earthworms
  • D. Male frogs

Solution

Related Formula

Haplodiploidy in Honeybees: Male (Drone, n = 16) Mitosis Sperm ( n = 16)

Core Logic

Male honeybees (drones) develop parthenogenetically from unfertilised haploid eggs (n = 16). Because their body cells are already haploid, they produce gametes (sperms) via mitosis rather than meiosis.

Step 1: Evaluation of Other Options

Male grasshoppers, earthworms, and frogs are diploid organisms (2n) and produce gametes through meiotic division.

Pattern Recognition

Sees: "haploid cells divide mitotically to produce gametes". Shortcut: Male honeybees (drones).

Chapter Mix

Class 12 Biology: Principles of Inheritance and Variation

More Principles of Inheritance and Variation Questions — neet_2024_05_may_morning

Practice all Principles of Inheritance and Variation previous-year questions →

Rankbit System
JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%) | JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%)