§-Quick questions
NSWBiologyModule 5: Heredity
Quick questions on Codominance, incomplete dominance and multiple alleles explained: HSC Biology Module 5
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 codominance?Show answer
In codominance, both alleles in a heterozygote are fully and simultaneously expressed. The phenotype shows both traits side by side, NOT blended.
What is incomplete dominance?Show answer
In incomplete dominance, the heterozygote shows an intermediate phenotype between the two homozygotes, as if the alleles had been blended.
What are multiple alleles?Show answer
Most genes in textbooks have just two alleles (e.g. A and a). In reality, many genes have multiple alleles in the population.
What is notation?Show answer
Use uppercase letters with superscripts. For ABO blood groups: and are codominant.
What is wrong allele notation for ABO?Show answer
Use , , and (lowercase i for recessive O). Writing A, B, O directly without the I superscript loses marks.
What is always give a key?Show answer
NESA markers repeatedly note that a key (e.g. = A antigen) is required to interpret a Punnett square. Write it even when it feels obvious.
What is state the ratio in the order phenotypes appear?Show answer
For a heterozygote cross write and name each phenotype - do not leave a bare ratio.
What is use correct notation throughout?Show answer
Superscript ABO alleles and consistent letters for incomplete dominance signal Band 5/6 control of the topic.