A Level Biology Practice Exam

What distinguishes homologous chromosomes?

1. They are genetically identical

2. They are functionally different from each other

3. They come from the same parent

4. They are a matching pair inherited from each parent

The correct answer is: They are a matching pair inherited from each parent

The correct response highlights that homologous chromosomes are a matching pair inherited from each parent. This characteristic is crucial in understanding how genetic diversity arises during reproduction. During sexual reproduction, an organism inherits one chromosome from the mother and one from the father for each pair. Although these chromosomes contain similar genes, they may have different alleles (variations of a gene), contributing to genetic variation in offspring. The other choices do not accurately define homologous chromosomes. Although homologous chromosomes carry similar genes, they are not genetically identical, as they can have different versions of the same gene from each parent. They are also not described as functionally different because they mainly perform the same roles in genetic functions, like contributing to traits. Lastly, while it’s true that they can come from the same parent, the defining feature of homologous chromosomes is that they are from both the mother and the father, emphasizing their nature as a pair rather than simply being traced to one parent.