Inheritance

Free sample questions

Inheritance — sample Biology questions with answers

1. Question 1

   What is the meaning of allele?

   • ASame gene on homologous chromosomes
   • BAlternative form of a gene at the same locus
   • CPaired homologous chromosomes
   • DObservable phenotype

   Answer: B. Alternative form of a gene at the same locus

   An allele is an alternative form of a gene located at the same locus on homologous chromosomes.

2. Question 2

   In a monohybrid cross between tall pea plants (TT) and short pea plants (tt), what is the phenotypic ratio of the F2 generation?

   • A$3:1$ (tall:short)
   • B$1:2:1$
   • C$9:3:3:1$
   • D$1:1$

   Answer: A. $3:1$ (tall:short)

   A monohybrid cross TT x tt produces F1 all Tt. When F1 is self-crossed, the F2 phenotypic ratio is 3 tall : 1 short (3:1).

3. Question 3

   An individual with genotype $Bb$ is known as...

   • AHomozygous dominant
   • BHomozygous recessive
   • CHeterozygous
   • DAllele

   Answer: C. Heterozygous

   Genotype $Bb$ contains two different alleles (B and b), hence the individual is heterozygous.

4. Question 4

   In flower colour inheritance, red (R) is dominant over white (r). What is the phenotype of the offspring if a cross between $RR$ and $rr$?

   • AAll red
   • BAll white
   • C$50\%$ red, $50\%$ white
   • D$75\%$ red, $25\%$ white

   Answer: A. All red

   Cross $RR$ (red) with $rr$ (white) produces all offspring $Rr$. Since R is dominant over r, all offspring have red phenotype.

5. Question 5

   Mendel's Law of Segregation states that...

   • AAlleles pair up during gamete formation
   • BAlleles separate during gamete formation
   • CAlleles assort independently
   • DAlleles remain together

   Answer: B. Alleles separate during gamete formation

   The Law of Segregation (Mendel's First Law) states that a pair of alleles separate during gamete formation, so each gamete carries only one allele.