inquiry lab- investigating cheese “microbiomes”
DESCRIPTION
Cheesy History 5000 BC (?) - Pouches made from animal stomachs likely provided the Rennet enzymes separating milk casein into curds and whey The practice of salting foods for preservation included curdled milk Late 1890’s - Identifying and culturing bacteria led to standardization of cheese productsTRANSCRIPT
Inquiry Lab- Investigating Cheese “Microbiomes”
Essential Question: How do biologists study living things?
Cheesy History• 5000 BC (?) - Pouches made from
animal stomachs likely provided the Rennet enzymes separating milk casein into curds and whey
• The practice of salting foods for preservation included curdled milk
• Late 1890’s - Identifying and culturing bacteria led to standardization of cheese products
Cheese Production
Ancient Biotechnology• Diversity of microbes in cheese making
Blue Cheese microbes on a Petri dish
Cheese as a model system
• Culturing cheese microbes is helping scientists learn about interactions within microbial communities
Different cheeses have different microbial communities
Resources (listed from popular to technical sources)
• Bacteria in Cheese• The Most Delicious Lab • Microbe Managing - The Life Saving
Potential of Cheese• Abstract: Diversity of Bacteria… in
Cheese Production • DNA technology reveals microbes in
cheese
Experimental Design
Doing things in a scientific way…. • Observe• Wonder• Question• PLAY (build a model, perform an
experiment)
ObserveCulture a cheese microbiome • Prepare nutrient agar in Petri dishes
– Determine number of dishes you will need– Weigh,measure, and mix powder in a flask– Stir and boil until solution turns translucent– Cool, then pour thin layers into plates
• Bring in cheese samples (washed rind)• Using sterile swabs innoculate agar from
cheese rind samples• After several days, LOOK at growth!
Wonder
• What kind of bacteria are growing?• Is the community stable or dynamic?• How could we change the community?
Question
• What condition causes a particular bacterial species to increase in number? Decrease in diversity? Die off completely?
Experimental Design Guidelines
• (IF) Independent Variable: condition or situation you will set up
• (THEN) Dependent Variable: – Must be quantitative– the NUMBER that you will record
IF/THEN hypothesis should reflect your question
• Hypothesis predicts how variables will change
• IF the temperature increases, THEN population of Bac A will increase. 0
102030405060708090
RoomTemp
Warm
Bac ABac BBac C
Data collection should reflect your question
• Independent Variable (x-axis) =
• Dependent Variable (y-axis) =
0102030405060708090
RoomTemp
Warm
Bac ABac BBac C