Biochemical Tests Lab

Isolation Media
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Isolation Media
Exercise 3: Isolation of microorganisms
Question 1: Differential Medium
A differential medium is a culture medium that allows for the separation of microorganism compounds based on the surrounding media and colony (Lewis et al., 2021). The media’s purpose is microbe identification by focusing on their reaction to dyes. The separation is done by considering biochemical differences.
Question 2: Selective Medium
Selective medium is a type of cultural medium composed of ingredients that limit microbial growth. Its use is to inhibit other organisms from growing while it allows others, thus makes selection easier.
Question 3: MacConkey agar
MacConkey plays different roles of differential and selective media; it is selective since it allows the growth of shigella by inhibiting the coliform group (Lewis et al., 2021). On the other hand, it is differential since it isolates micro-organisms causing diseases such as paratyphoid.
Question 4: Blood Agar
Blood agar enhances bacterial growth. It is also used due to its non-selective nature thus effective in both anaerobic and aerobic laboratories.
Question 5: MTM and Chocolate Agar
Chocolate agar is a blood type of agar composed of agents that stimulates Neisseria’s growth. On the other hand, MTM is a type of chocolate agar composed of inhibitory agents and is majorly used for sexually transmitted diseases. MTM is used in cases of identifying gonorrhea and not chocolate agar.
Exercise 4: Pure Bacterial Colonies
Question 1: Sterilization
The loop is sterilized to prevent microbe contamination. The contamination may result from different impurities. It is advisable to flame the loop after every inoculum.
Question 2: Mixed culture and pure culture
Mixed culture contains more than one type of bacteria, while single culture contains a single type of bacteria...