BIOD 171 Module 4 Exam questions and 100% correct answers

What is another name for a liquid growth media, and what are the basic components? - correct answer Growth media in a liquid form is often referred to as nutrient broth. As the name implies its composition consists primarily of essential 'ingredients' such as a rich source of sugars, amino acids, and vitamins. Together, a nutrient broth provides the microbe with a source of carbon/energy, which, in turn, encourages its expansion. What is selective media? - correct answer Selective media allows for only the growth of certain microbes while restricting the growth of all others. What is differential media? - correct answer Differential media is used to distinguish between two (or more) related microbes. What are the requirements of a fastidious microbe? - correct answer A fastidious microbe is an organism with complex growth requirements such that if absent it will not grow. Enriched medias thus contain these specific and essential nutrients required for the growth of a particular subset of microorganisms. What is agar? - correct answer In its simplest form agar is liquid growth media that has had a hardening agent added to it. Agar is created when a polysaccharide derived from seaweed (algae) extract is added to growth media. Agar is used to create a solid, smooth surface on which microbes can grow. LB agar is classified as a non-selective, differential media True False - correct answer False LB agar is non-selective and non-differential What are the three forms of hemolysis found on blood agar plates? - correct answer Alpha hemolysis, beta hemolysis, and gamma hemolysis Alpha hemolysis - correct answer Presents with greenish-brown color on blood agar due to the partial lysis of red blood cells Beta hemolysis - correct answer Clear zones on blood agar indicate beta hemolysis, which is the complete lysis of red blood cells Gamma hemolysis - correct answer Presents a white/tan on blood agar due to the lack of hemolytic activity.