There may be many reasons why a yeast cell cannot grow on a simple food source that has no supplements, but one good reason is that it cannot make all the vital ingredients and molecules it needs for metabolism. Haploid yeast cells are particularly vulnerable as they only contain one copy of each vital gene.

In which of the following links is outcome of damage to vital metabolic pathways in haploid cells discussed, and ways of keeping these cells alive described?

When cells contain more than one copy of each and every gene, these genes can complement each other in ways that increase the survival chances of a cell which contains damaging mutations. One way of increasing the number of copies of a set of genes in a cell is to fuse together two haploid cells to form one diploid cell.

In which of the following links is one possible outcome described when mutants occurring in two different genes in the same metabolic pathway find themselves in the same cell?

Mitosis and meiosis are two very different types of eukaryotic cell division with very different purposes and outcomes. Haploid yeast cells can only divide by mitosis, but diploid yeast cells can do both.

In which of the following links is the main genetic effect on the status and quantity of biological information discussed as yeast cells move from the diploid to the haploid number of chromosomes?

Yeast cells that contain more than one copy of each gene also contain more than one copy of each chromosome. This presents a problem during meiotic cell division, when these almost identical copies of chromosomes need to find each other before permanently separating.

In which of the following links is this problem addressed and the pairing process described?