Practice IB Biology Topic D3.2 Inheritance with authentic exam-style questions for both SL and HL students. This question bank focuses on the exact syllabus content for D3.2 Inheritance and mirrors Paper 1A, 1B, 2 style where relevant.
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Cuttings from one clone grew under two light conditions, then under the same light. Which conclusion is supported?
| Group | Initial light | Initial leaf area / cm² | Initial thickness / mm | New-leaf area under same light / cm² |
|---|---|---|---|---|
| P | low | 80 | 0.20 | 54 |
| Q | high | 35 | 0.50 | 56 |
…
The Punnett square represents a cross between a red-flowered plant () and a white-flowered plant (), producing all heterozygous offspring () with pink flowers.
If an heterozygote () self-pollinates, what is the expected phenotypic ratio?
The pedigree shows a rare disorder with complete penetrance and no new mutations. Which inheritance pattern is supported?
Inheritance patterns follow predictable rules. Answer the following questions about inheritance and genetic patterns.
(a) between genotype and phenotype.
(b) how a Punnett square can be used to determine the probability of inheritance of a trait.
(c) how the inheritance of sex-linked traits differs from autosomal traits.
For an X-linked recessive disorder, the mother is XᴴXʰ and the father XᴴY. Which outcome is expected?
100% pink flowers
50% red, 50% white
25% red, 50% pink, 25% white
75% pink, 25% red
Autosomal dominant, because affected offspring occur in both sexes.
X-linked recessive, because affected sons can have unaffected mothers.
Y-linked, because the affected son inherited the allele from his unaffected father.
Autosomal recessive, because unaffected parents have an affected daughter and son.
1/2 affected; all affected offspring are female
1/4 affected; all affected offspring are female
1/4 affected; all affected offspring are male
1/2 affected; all affected offspring are male
