A Level Biology (A2) chapter 5: Inheritance MCQs with answers
By Team Megalecture · Updated 4 Nov 2026
61 exam-style questions on Inheritance, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.
Passage of information from parents to offspring18 questions
The roles of genes in determining the phenotype29 questions
Gene control14 questions
Ten Inheritance questions with answers
Try each one, then open the answer. These ten stay the same; the test draws new ones every time.
1. A dwarf pea plant of genotype lele is sprayed regularly with active gibberellin and grows as tall as a plant of genotype LeLe. Which conclusion is supported?
A
the spraying has changed the plant's genotype, so its offspring will also grow tall
B
the le allele codes for a faulty receptor
C
gibberellin makes the stem taller only by increasing the rate of cell division in the roots
D
the plant can respond to gibberellin but cannot make enough of it
Show answer
Answer: D. Adding the hormone restores normal growth, so the plant's response pathway works and its problem is making active gibberellin, as expected for a non-functional enzyme. A change in phenotype caused by spraying does not change the genotype, so the offspring will still be lele dwarfs.
2. In a heterozygote, both alleles of a gene are fully expressed in the phenotype. Which term describes these alleles?
A
codominant
B
recessive
C
homozygous
D
linked
Show answer
Answer: A. Codominant alleles are both expressed in a heterozygote, as with IA and IB in blood group AB. A recessive allele is not expressed when a dominant allele is present; linked genes are at different loci on one chromosome.
3. A photomicrograph of an anther shows a cell in which four new nuclear envelopes have formed. Each of the four nuclei contains a haploid set of chromosomes made of single chromatids. Which stage of meiosis has been reached?
A
telophase II
B
telophase I
C
anaphase II
D
prophase II
Show answer
Answer: A. Four haploid nuclei, with chromosomes of single chromatids, are the product of the second division, so this is telophase II. Telophase I gives two nuclei whose chromosomes still have two chromatids.
4. Why are X-linked recessive conditions, such as haemophilia, more common in males than in females?
A
the recessive allele is carried on the Y chromosome, which only males have
B
a male always inherits his only X chromosome from his father
C
the recessive allele behaves as a dominant allele in male body cells
D
a male has one X chromosome, so a single recessive allele is expressed
Show answer
Answer: D. The Y chromosome has no locus for the gene, so a male with one Xh has no dominant allele to mask it. A female needs two recessive alleles, one from each parent. Sons inherit their X chromosome from their mother.
5. Which statement about transcription factors in eukaryotes is correct?
A
they are short RNA molecules that bind to ribosomes and stop translation
B
they are proteins that bind to DNA and increase or decrease the rate of transcription
C
they are enzymes that remove the introns from primary transcripts in the nucleus
D
they are proteins that bind to mRNA in the cytoplasm and speed up translation
Show answer
Answer: B. Transcription factors are proteins that bind to specific DNA sequences, often near a promoter, and either help or hinder RNA polymerase, so they increase or decrease the rate of transcription of particular genes.
6. Albinism can be caused by mutations in the TYR gene. What is the role of the protein coded for by the functional allele of this gene?
A
it is tyrosinase, an enzyme in the pathway that makes melanin
B
it is a transport protein that carries melanin into skin and hair cells
C
it is a hormone that stimulates skin cells to take up the amino acid tyrosine
D
it is a melanin receptor on cells of the iris
Show answer
Answer: A.TYR codes for tyrosinase, which catalyses early steps in converting the amino acid tyrosine into the pigment melanin. With no functional tyrosinase, little or no melanin is made, so skin, hair and eyes lack pigment.
7. What is the role of the operator in the lac operon?
A
it is the base sequence to which RNA polymerase first binds to start transcription
B
it is the regulatory gene that codes for the repressor protein
C
it is where the repressor protein binds, blocking transcription
D
it is the structural gene that codes for the lactose permease protein
Show answer
Answer: C. When the repressor is bound to the operator, RNA polymerase cannot move along to transcribe the structural genes. RNA polymerase binds at the promoter, and the repressor is coded for by the separate regulatory gene, lacI.
8. Male honeybees (drones) develop from unfertilised eggs and have 16 chromosomes in their body cells. Female honeybees develop from fertilised eggs and have 32. Which statement is correct?
A
the body cells of a drone are diploid, with 8 homologous pairs of chromosomes
B
the body cells of a female bee contain 32 complete sets of chromosomes
C
the body cells of a drone are haploid, with one set of 16 chromosomes
D
the body cells of a drone contain 16 homologous pairs of chromosomes
Show answer
Answer: C. An unfertilised egg carries one set of chromosomes, so the drone is haploid (n = 16) and has no homologous pairs. Females, from fertilised eggs, are diploid: two sets, 2n = 32, arranged as 16 homologous pairs.
9. An organism has a diploid number of 12. Ignoring crossing over, how many genetically different combinations of chromosomes could its gametes have as a result of the random orientation of homologous pairs at metaphase I?
A
4096
B
64
C
12
D
36
Show answer
Answer: B. There are 6 homologous pairs, and each pair can line up in either of two ways, so the number of combinations is 26 = 64. Using 212 treats the diploid number, not the number of pairs, as the exponent.
10. A photomicrograph of a dividing cell in a lily anther shows a single spindle. Chromosomes are moving apart in two groups, and each chromosome moving towards a pole still consists of two chromatids joined at a centromere. Which stage of meiosis is shown?
A
anaphase II
B
metaphase I
C
telophase II
D
anaphase I
Show answer
Answer: D. Chromosomes that still have two chromatids are moving to the poles, so whole chromosomes (homologues) are being separated: anaphase I. In anaphase II the centromeres have divided and single chromatids move apart.
61, each with the answer and a short explanation, across 3 topics: Passage of information from parents to offspring, The roles of genes in determining the phenotype, Gene control. Every chapter test draws ten of them, so you can take it many times.
Is the A Level Biology (A2) chapter 5 test free?
Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.
How is the chapter test marked?
The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.
