Inheritance Practice Questions
IGCSE (Cambridge) · IGCSE Biology · 139 free MCQs with instant results and detailed explanations.
139
Total
36
Easy
73
Medium
30
Hard
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Sample Questions from Inheritance
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
What is the primary function of DNA in living organisms?
A.
To provide energy for cellular processes
B.
To store and transmit genetic information
C.
To regulate the temperature of cells
D.
To break down waste materials
Show Answer & Explanation
Correct Answer: B
DNA stores genetic information and is responsible for the transmission of hereditary traits from parents to offspring, making it essential for inheritance.
Q2
Easy
Which of the following is an example of a phenotype?
A.
The genetic makeup of an organism
B.
The color of a flower
C.
The number of chromosomes
D.
The DNA sequence
Show Answer & Explanation
Correct Answer: B
A phenotype refers to the observable characteristics of an organism, such as the color of a flower, which results from the interaction of its genotype with the environment.
Q3
Easy
In a monohybrid cross between two heterozygous pea plants (Tt), what is the expected phenotypic ratio of the offspring?
A.
1:1
B.
3:1
C.
9:3:3:1
D.
1:2:1
Show Answer & Explanation
Correct Answer: B
In a monohybrid cross of Tt x Tt, the expected phenotypic ratio of dominant to recessive traits in the offspring is 3:1, where 3 express the dominant phenotype and 1 expresses the recessive phenotype.
Q4
Medium
What is the primary function of alleles in genetics?
A.
To determine phenotypic traits
B.
To provide energy for cellular processes
C.
To facilitate digestion in organisms
D.
To synthesize proteins
Show Answer & Explanation
Correct Answer: A
Alleles are different forms of a gene that determine specific traits in an organism, influencing phenotypes such as eye color or flower color.
Q5
Medium
In a monohybrid cross, what is the expected phenotypic ratio of the offspring when two heterozygous parents are crossed?
A.
1:1
B.
3:1
C.
9:3:3:1
D.
1:2:1
Show Answer & Explanation
Correct Answer: B
In a monohybrid cross between two heterozygous parents (Tt x Tt), the expected phenotypic ratio is 3 dominant to 1 recessive, hence 3:1.
Q6
Medium
Which of the following best describes a phenotype?
A.
The genetic makeup of an organism
B.
The observable physical traits of an organism
C.
The location of genes on a chromosome
D.
The process of genetic variation
Show Answer & Explanation
Correct Answer: B
A phenotype refers to the observable characteristics or traits of an organism, which are influenced by its genotype and the environment.
Q7
Medium
If a gene for flower color in pea plants has two alleles, red (R) and white (r), what will be the color of the flowers in a plant with the genotype Rr?
A.
Red
B.
White
C.
Pink
D.
No flowers
Show Answer & Explanation
Correct Answer: A
The red allele (R) is dominant over the white allele (r). Therefore, a plant with the genotype Rr will exhibit the red phenotype.
Q8
Hard
A genetic trait for height in a certain plant species is influenced by two pairs of alleles. If a plant has the genotype AABb, what fraction of its gametes will carry the dominant allele A?
A.
1/2
B.
3/4
C.
1/4
D.
1
Show Answer & Explanation
Correct Answer: B
The plant AABb can produce four types of gametes: AB, Ab, AB, Ab. Three of these gametes carry the dominant allele A, leading to a fraction of 3/4.
Q9
Hard
In a dihybrid cross involving two traits, if two parents are both heterozygous for two traits (AaBb), what is the expected phenotypic ratio of the offspring?
A.
1:2:1:2:1:2
B.
9:3:3:1
C.
3:1
D.
1:1:1:1
Show Answer & Explanation
Correct Answer: B
The expected phenotypic ratio from a dihybrid cross of two heterozygous parents (AaBb) is 9:3:3:1. This means that 9 offspring will express both dominant traits, 3 will express one dominant and one recessive trait, another 3 will express the other dominant and recessive trait, and 1 will express both recessive traits.
Q10
Hard
If a plant species exhibits incomplete dominance for flower color, where red (RR) crosses with white (WW) to produce pink (RW), what would be the expected phenotypic ratios of the F2 generation if two pink plants are crossed?
A.
1 red: 2 pink: 1 white
B.
1 pink: 1 white
C.
3 pink: 1 white
D.
1 red: 1 pink: 1 white
Show Answer & Explanation
Correct Answer: A
When two pink plants (RW) are crossed, the expected F2 generation will have a phenotypic ratio of 1 red (RR): 2 pink (RW): 1 white (WW). This results from the combinations of genotypes (RR, RW, WW) from the cross.
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Inheritance — IGCSE (Cambridge) IGCSE Biology Practice Questions Online
This page contains 139 practice MCQs for the chapter Inheritance in IGCSE (Cambridge) IGCSE Biology. The questions are organized by difficulty — 36 easy, 73 medium, 30 hard — so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.