What are homologous chromosomes?

Question

What are homologous chromosomes?

A. An original chromosome and its exact copy

B. The two halves of a chromosome

C. Two genetically identical chromosomes, one from each parent

D. A pair of "matching" but not identical chromosomes, one inherited from each parent

Answer 1

I would have to say D, as the chromosomes code for the same traits but are a pair of chromosomes being one from each parent and therefore not identical.

Answer 2

Think of homologous chromosomes as a set of chromosomes that corresponds to each other from each side: in humans 46 total 23 pairs, one from each side so

D would be the best answer.

Answer 3

Homologous chromosomes are different DNA molecules which contain the genetic code for the same genes, but not necessarily the same version of the genes (a version of a gene is called an allele). As an example, all humans have two copies of each gene, one from each parent, existing on separate physical chromosomes. Since the chromosomes contain the same genes, but not necessarily the same version of each gene, they are called homologous chromosomes. For instance, in each cell of your body, you have two chromosome 1 molecules, but each will contain a different sequence of DNA bases, corresponding to different versions of genes (as well as different non-coding regions). Those are are an example of homologous chromosomes.

Since homologous chromosomes contain the genetic code for the same genes, but do not contain the exact same DNA sequence, they are "matching", but they are not identical molecules. Therefore, d) is the correct answer.

Answer 4

There are a lot of names for the condensed DNA in cells and while they all sound very similar, they each have a specific meaning. When the DNA in a cell is duplicated (i.e. an exact copy is made) during mitosis, the result is two sister chromatids, which is what they are referring to in choice B. Two of these identical sister chromatids are joined together at the centromere to form a chromosome. Diploid organisms (like us and other animals) have two copies of each chromosome- one from mom, and one from dad (the only exception is with sex chromosomes: males have one X and one Y chromosome, but don't worry about that for this question). Each set of homologous chromosomes have the same genes in the same locations (loci), but they aren't genetically identical. And just to clarify it visually, if you see a picture/drawing of a thing that look like an X, that's a chromosome, and the single bars are chromatids. I hope this helps!