A sample from a stock of a bacterial colony in liquid media was diluted by a factor of 106, and 2 ml of this dilution was spread on a Petri dish of solidified media. 56 colonies were observed. What was the concentration of bacteria of the initial stock?

28 × 10⁶ colonies/ml

Explanation:

Let C be the concentration of bacterial in the initial stock. When it is diluted by a factor of 10⁶, the new concentration is C' = C/10⁶.

When 2 ml of this concentration is spread on a Petri dish of solidified media, 56 colonies were produced. The number of colonies, n after spreading the 2 ml of C' is C' × 2 ml = 2C' = 2C/10⁶.

So, n = 2C/10⁶.

Since the number of colonies after spreading on a Petri dish of solidified media is 56, n = 56 colonies.

So, 2C/10⁶ = 56

Making C subject of the formula, we have

C = 56 × 10⁶/2

C = 28 × 10⁶ colonies/ml

So, the initial concentration of bacteria is 28 × 10⁶ colonies/ml

ans.

gregor john mendel is known for study of inheritance in pea plants. he used garden pea plant for his study, having alternative traits for various characters. he performed cross-breeding in pea plants to check how characters are transmitted between parents to offspring, such as cross between pure tall and pure dwarf plant. mendel studied the inheritance patterns in pea plants for various generations.

thus, the correct answer includes options and f).