Specific growth rate is defined as the increase in cell

Cell (biology)

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

 mass per unit time, e.g., grams cells (g) per gram cells (g) per hour: (). The specific growth rate is commonly given by the symbol, µ (mu

Mu

- Language :* Mu , Μ or μ, a letter in the Greek alphabet* Mu , represented by the Japanese kana む or ム* 無, Mu , a Japanese and Korean word important in Zen practice...

), and the most common units are in reciprocal hours (h⁻¹); however, it can also be expressed in reciprocal seconds (s⁻¹) or minutes (min⁻¹) or any other units of time.

Formula

Specific growth rate can be calculated from:

,

where are biomasses at the different timepoints (t₁ and t₂) respectively

When looking for doubling time, then use that and the doubling time t_d is t₂ - t₁.

Specific growth rate constant

Specific growth rate constant is a way of measuring how fast the cells are dividing

Cell division

Cell division is the process by which a parent cell divides into two or more daughter cells . Cell division is usually a small segment of a larger cell cycle. This type of cell division in eukaryotes is known as mitosis, and leaves the daughter cell capable of dividing again. The corresponding sort...

in a culture. It is defined on the basis of doubling rate, and mathematically it can be explained by the following formula:

k = 1/Log 2 x 1/t x (Log N_t - Log N_o)

it can be modified as:

k= 3.32 x 1/t x (Log N_t - Log N_o)

where k= growth rate constant

N_t = number of bacteria at a time t

N_o = number bacteria at start

t = time.