Inheritance Variation and Evolution Practice Questions
GCSE · GCSE Biology · 148 free MCQs with instant results and detailed explanations.
148
Total
44
Easy
74
Medium
30
Hard
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Sample Questions from Inheritance Variation and Evolution
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Q1
Easy
What is the primary purpose of meiosis in organisms?
A.
To produce gametes with half the number of chromosomes
B.
To repair damaged tissues
C.
To create identical copies of cells
D.
To increase the size of cells
Show Answer & Explanation
Correct Answer: A
Meiosis is the process that creates gametes (sperm and eggs) with half the number of chromosomes, which is essential for sexual reproduction.
Q2
Easy
In a plant, the allele for tallness (T) is dominant over the allele for shortness (t). What would be the phenotype of a plant with the genotype Tt?
A.
Tall
B.
Short
C.
Medium
D.
Varied
Show Answer & Explanation
Correct Answer: A
The presence of the dominant allele (T) in the genotype Tt means that the phenotype will express tallness, as dominant traits override recessive ones.
Q3
Easy
Which of the following best describes natural selection?
A.
The process where organisms with favorable adaptations survive and reproduce
B.
The random mixing of genes during reproduction
C.
The intentional breeding of organisms by humans
D.
The isolation of species into different habitats
Show Answer & Explanation
Correct Answer: A
Natural selection is the mechanism by which individuals with traits better suited to their environment tend to survive and reproduce more than those without those traits.
Q4
Medium
Which of the following describes the process by which alleles are randomly distributed to gametes during meiosis?
A.
Independent assortment
B.
Segregation
C.
Crossing over
D.
Genetic drift
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Correct Answer: A
Independent assortment is the process during meiosis where alleles are distributed randomly into gametes. This contributes to genetic variation in offspring.
Q5
Medium
If a plant with genotype AaBb produces gametes, what fraction of its gametes will be dominant for both traits?
A.
1/4
B.
1/2
C.
3/8
D.
1/8
Show Answer & Explanation
Correct Answer: A
The plant can produce four types of gametes (AB, Ab, aB, ab) with only one (AB) showing dominance for both traits. Therefore, the fraction is 1 out of 4.
Q6
Medium
Which type of mutation is characterized by the replacement of one nucleotide with another in a DNA sequence?
A.
Frameshift mutation
B.
Silent mutation
C.
Substitution mutation
D.
Deletion mutation
Show Answer & Explanation
Correct Answer: C
A substitution mutation occurs when one nucleotide is replaced by another in the DNA sequence, potentially altering the amino acid sequence of the resulting protein.
Q7
Medium
In a population of rabbits, if a trait for fur color is controlled by a single gene with two alleles, black fur (B) being dominant to brown fur (b), what proportion of offspring will be expected to have black fur if two heterozygous rabbits are crossed?
A.
100%
B.
75%
C.
50%
D.
25%
Show Answer & Explanation
Correct Answer: B
When two heterozygous rabbits (Bb x Bb) are crossed, the expected phenotypic ratio of the offspring is 3:1. Thus, 75% of the rabbits will have black fur.
Q8
Hard
In a certain plant species, flower color is determined by a single gene with two alleles: R (red) and r (white). In a population of these plants, 36% have red flowers. If the population is in Hardy-Weinberg equilibrium, what is the frequency of the recessive allele (r)?
A.
0.4
B.
0.6
C.
0.2
D.
0.8
Show Answer & Explanation
Correct Answer: B
To find the frequency of the recessive allele (r), we first determine the frequency of the homozygous recessive genotype (rr), which is given as 0.36 (36%). The formula p^2 + 2pq + q^2 = 1 allows us to find q^2 = 0.36, thus q = √0.36 = 0.6, indicating the frequency of allele r is 0.6.
Q9
Hard
A population of rabbits exhibits a variation in fur color determined by multiple alleles. If a rabbit with genotype AaBb is crossed with a rabbit of genotype AAbb, what is the probability that their offspring will be homozygous for both traits?
A.
1/4
B.
1/2
C.
1/8
D.
1/16
Show Answer & Explanation
Correct Answer: A
To calculate the probability of getting homozygous offspring for both traits (AAbb), we need to evaluate the combinations from the cross. The AaBb rabbit can produce gametes AB, Ab, aB, and ab, while the AAbb rabbit can produce gametes Ab and Ab. The homozygous outcome AAbb can arise from the AA from the AaBb and the bb from AAbb, resulting in a probability of 1/4.
Q10
Hard
A genetic cross is performed between two plants, one homozygous dominant for flower color (RR) and one homozygous recessive (rr). What is the expected phenotype ratio of the offspring if the R allele is completely dominant over the r allele?
A.
All offspring will have red flowers.
B.
1 red: 1 white flower.
C.
3 red: 1 white flower.
D.
All offspring will have white flowers.
Show Answer & Explanation
Correct Answer: A
The homozygous dominant (RR) plant will produce offspring that are all heterozygous (Rr), displaying the dominant phenotype, which is red flowers. Therefore, all offspring will have red flowers.
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Inheritance Variation and Evolution — GCSE GCSE Biology Practice Questions Online
This page contains 148 practice MCQs for the chapter Inheritance Variation and Evolution in GCSE GCSE Biology. The questions are organized by difficulty — 44 easy, 74 medium, 30 hard — so you can choose the right level for your preparation.
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