Yeast Culture in Conditions of Limited Reproduction, Additional Food and Introduced Predation

Introduction

Reproduction is the biological process by which new individual organisms called “offsprings” are produced from or by the existing organisms called “parents”.
Reproduction can be asexual (such as simple cell division observed in unicellular organisms, but also cloning of both unicellular and multicellular organisms) and sexual, depending on whether the process requires the sexual interaction, which enables the combination of the parental genetic material, usually through, but not limited to, the merging of specialized (typically haploid) cells called “gametes”.

If the reproduction requires sexual interaction, it is sexual; if the process does not involve any type of sexual interaction, it is asexual.
Yeast (Saccharomyces cerevisiae) is a unicellular eukaryote which can exist both in haploid and diploid mode.

All yeast cells can reproduce asexually, however, mating of yeast occurs exclusively between haploids, called spores.
There are two types of spores: “a” and “α”, which mate with each other. Spores of the same type cannot mate among themselves.
Sexual differentiation of diploid cells occurs only under stressful conditions, such as nutrient depletion (Cap, Vachova & Palkova, 2009, 2010).

In such conditions, a diploid cell undergoes meiosis to produce haploid spores (the process is called “sporulation”) – two “a” spores and two α spores, four in total, which can go on to mate in a process called “conjugation”. a cells produce a-factor, a mating pheromone, which attracts the neighboring α cells. a cells respond to α-factor, the α cell pheromone, by growing a projection, called

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