Question

Outline the mechanism of forming pre-replicative complex and subsequent initiation at origins. Why is budding yeast useful in studying cell cycle analyses? Identify the morphological changes that occur in budding yeast during the cell cycle.

Answer 1

The pre-replicative complex (pre-RC) formation at origins of replication is initiated by ORC binding and is followed by the assembly of additional factors, leading to DNA replication initiation. Budding yeast is a valued model for cell cycle studies due to its similarity to human cells, genetic tractability, and rapid cell cycle. Key morphological changes during its cell cycle include bud formation and division.

Step-by-step explanation:

Replication in eukaryotic cells begins with the formation of the pre-replicative complex (pre-RC) at origins of replication. This complex formation is a multi-step process initiated during the G1 phase when ORC (origin recognition complex) binds to the DNA. Subsequently, other key proteins including Cdc6 and Cdt1 bind and assist in the recruitment of the MCM (minichromosome maintenance) helicase, completing the pre-RC.

Budding yeast (Saccharomyces cerevisiae) is a powerful model organism for studying the cell cycle due to its eukaryotic similarity to human cells, ease of genetic manipulation, and rapid growth. Morphological changes in budding yeast during the cell cycle include the formation and growth of a bud, nucleus division and migration into the bud, and cytokinesis resulting in separation of the daughter cell.