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VICBiologyQuick questions
Unit 2: How does inheritance impact on diversity?
Quick questions on Monohybrid crosses and test crosses: VCE Biology Unit 2
8short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is setting up a monohybrid cross?Show answer
A monohybrid cross considers one gene with two alleles.
What is the four basic monohybrid crosses (autosomal dominant pattern)?Show answer
Using P (purple, dominant) and p (white, recessive).
What is the test cross?Show answer
A test cross is the cross between an organism showing the dominant phenotype (unknown genotype: PP or Pp) and a homozygous recessive organism (pp).
What is 3. Heterozygous times homozygous recessive?Show answer
This is the test cross.
What is sample-size caveat?Show answer
With small numbers of offspring, a heterozygous parent might by chance produce all-dominant offspring just from random gamete sampling. The more offspring observed, the more confident the conclusion.
What is q1?Show answer
Define a test cross and state its purpose. [2 marks]
What is q2?Show answer
A dark-berry Pinot Noir vine is crossed with a light-berry vine. Of 80 offspring, 41 are dark and 39 are light. State the genotype of the dark parent and justify with a Punnett square.
What is q3?Show answer
A pea plant breeder crosses tall (T) and short (t) pea plants. (a) State the genotype of a true-breeding tall plant. (b) Predict the F1 phenotype if a true-breeding tall is crossed with a true-breeding short.