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Inheritance MCQs for MDCAT Practice

Biology section, Inheritance chapter. Up to eight free sample questions, each with the correct answer and a worked explanation. The full chapter opens in the app.

The bank has 1,809 active questions on this chapter. Your first 500 practice attempts are free, and every attempt includes a worked explanation.

  1. Question 1
    In the study of heredity, scientists examine how traits are passed from parents to offspring. This area of biology considers patterns of inheritance and how genetic information is transmitted across generations. Early research in this field involved the use of model organisms to track the appearance of observable traits. By analyzing these patterns, researchers began to develop principles that explain how traits can appear in some generations but not others. Today, these principles continue to inform modern genetics and our understanding of inheritance in both plants and animals. Which of the following best describes a genotype?
    • The observable characteristics of an organism
    • The environment's influence on a trait
    • The evolutionary origin of a gene
    • The specific allele combination an organism carries (correct answer)
    Correct answer: D
    Distinguishes genotype (genetic makeup) from phenotype (observable traits) and other genetic concepts, crucial for understanding inheritance patterns.
  2. Question 2
    Child death may occur in the marriage of:
    • Rh+ man and Rh+ woman
    • Rh+ man and Rh– woman (correct answer)
    • Rh– man and Rh– woman
    • Rh– man and Rh+ woman
    Correct answer: B
    Rh incompatibility can cause hemolytic disease of the newborn, leading to fetal death, primarily when an Rh- mother carries an Rh+ fetus.
  3. Question 3
    ABO blood grouping is controlled by gene I which has three alleles and show co-dominance. There are six genotypes. How many phenotypes in all are possible?
    • Six
    • Four (correct answer)
    • Three
    • Five
    Correct answer: B
    ABO blood groups showcase multiple alleles and codominance. This question tests understanding of genotype-phenotype relationships in human genetics.
  4. Question 4
    Which group of animals has heterogametic females?
    • Domestic fowl (correct answer)
    • Earthworm
    • Rabbit
    • None of these
    Correct answer: A
    This question tests understanding of sex determination mechanisms, specifically heterogametic sex, differentiating between males and females.
  5. Question 5
    One of the parents of a cross has a mutation in its mitochondria. In that cross, that parent is taken as a male. During segregation of F2 progenies that mutation is found in:
    • One-third of the progenies
    • None of the progenies (correct answer)
    • All the progenies
    • Fifty percent of the progenies
    Correct answer: B
    Mitochondrial inheritance in crosses follows maternal patterns, not paternal ones, as mitochondria are primarily inherited via the egg cell.
  6. Question 6
    The process of determining the locus for particular biological traits includes?
    • Replication
    • Recombination
    • Gene mapping (correct answer)
    • None of these options is correct
    Correct answer: C
    Gene mapping pinpoints the location of genes on chromosomes, crucial for understanding trait inheritance and genetic diseases.
  7. Question 7
    A haemophilic male marries a haemophilia B carrier female have 4 children. 1 of their children is haemophilic and the remaining 3 are normal. What is the probability that their next child will be haemophilic?
    • 25%
    • 50% (correct answer)
    • 75%
    • 100%
    Correct answer: B
    Haemophilia B is X-linked recessive. A haemophilic male (X^h Y) and a carrier female (X^H X^h) have a 50% chance of producing an affected son (X^h Y) with each pregnancy.
  8. Question 8
    Inheritance of 4’O clock plant exhibits:
    • Complete dominance
    • Incomplete dominance (correct answer)
    • Codominance
    • Over-dominance
    Correct answer: B
    The 4'o clock plant's flower color inheritance, where red and white alleles produce pink heterozygotes, exemplifies incomplete dominance, not full expression of either parental trait.

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