Microbiology Lab Exam 1 2025 Questions & Answers with 100% Correct Answers | Verified

What is the purpose of a streak plate? - 1) To separate cells so that they grow to form isolated colonies 2) To confirm if a culture is a pure colony or mixed 3) To confirm is there is contamination in your culture What is a colony? - Areas of growth that arise from a single cell. How do colonies form? - They are formed by spreading out cells. Cells are spread and reproduce over and over again through bionary fission until visable mass of cells appear. What is a pure culture? - Culture containing only one type of organism What kind of media are colonies able to form on? - agar slant, broth media, agar plate When is a agar slant used? Pros & cons - 1) Smaller amount of surface area prevents the media from drying out too quickly 2) useful for medium term storage 3) viable for a couple of months if stored properly What are the 4 criteria for labeling a microbial culture? - 1) initials or name AND group number 2) date 3) growth media type 4) culture name or source of inoculum Describe bacillus (bacilli) morphology - rod shaped cells, longer than wide, sausage like, can use rod or bacillus describe coccus morphology - cells are ball shaped or spherical