Chapter 1.2, Problem 20E

Yeast growth Consider a colony of yeast cells that has the shape of a cylinder. As the number of yeast cells increases, the cross-sectional area A (in mm²) of the colony increases but the height of the colony remains constant If the colony starts from a single cell, the number of yeast cells (in millions) is approximated by the linear function N(A) = C_sA, where the constant C_s is known as the cell-surface coefficient Use the given Information to determine the cell-surface coefficient for each of the following colonies of yeast cells, and find the number of yeast cells m the colony when the cross-sectional area A reaches 150 mm². (Source: Letters in Applied Microbiology, 594, 59, 2014)

20.    The yeast Rhodotorula glutinis is a laboratory contaminant. When the cross-sectional area of a colony reaches 100 mm², there are 226 million yeast cells.