Question

3.

Which of the following statements is TRUE?

	The regulatory proteins produced by the MATa and MAT? alleles are identical and are found in all three yeast mating types.
	Unlike the MATa allele, the MAT? allele can actually produce two proteins, ?1 and ?2, which function as an activator and repressor, respectively.
	In yeast cells, the Mcm1 protein is encoded by the MATa allele and as such is only present in a cells.
	The MAT gene is the only gene involved in determining yeast-mating type.
	None of the answers is correct.

Answer 1

D. The MAT gene is the only gene involved in determining yeast mating type

Because yeast is a single celled eukaryotic with both diploid and haploid mode of existence.The mating of yeast cells occurs in haploid which can be either the a or . The mating type is determined by the single locus MAT inturn governs the sexual behaviour of the both haploid and diploid cells. The genetic recombination of the haploid cells can switch mating type as often of every cell cycle.