Bacteria basics
These single-celled organisms are found in soil, on various surfaces, in our bodies, and pretty much everywhere!
What are bacteria
We grow bacteria on plates that have a layer of jello-like substance called:
What is agar?
What does CFU stand for?
What are colony forming untis?
Where is agar extracted from?
seaweed/ algae
Bacteria are classified as this type of cell, meaning they don't have a nucleus or any membrane-bound organelles
What are prokaryotic cells
What is penicillin?
Since bacteria are too small to see with our bare eyes, what tool can we use to magnify the bacteria and visualize them?
What is a microscope?
one colony originates from how many cells?
ONE viable cell
Why did we use 70% ethanol after doing the agar art activity?
To kill any extra bacteria
Name three shapes that bacteria could be
Cocci (spheres), bascillus (rod), spirilla (spirals)
Who was the scientist that discovered Penicillin?
Alexander Fleming
This technique is used to avoid contamination when working with bacteria.
What is aseptic technique?
What is one way that antibiotics resistance occurs?
Mutations or gene transfer...etc.
What is measured in liquid cultures to look at bacterial growth
The optical density, aka how much light passes through the culture. The more light the passes through, the less bacterial growth.
List two characteristics of bacteria that are different compared to humans
Answers may vary....could include:
- They are only made of one cell
- Their DNA is circular, our's is linear
- We have membrane bound organelles
What is it called when bacteria can survivie antibiotics?
What is antibiotic resistance?
Why are agar plates incubated upsidedown?
To prevent condensation from dripping down onto the agar.
What does a larger zone of inhibition around an antibiotic disc mean?
The bacteria are more sensitive to that antibiotic?
Why do we work around a flame when working in the lab?
To reduce contamination of our experiments from bacteria in the air. We have to be super cautious when doing this!
Give 2 examples of bacteria
any two.... E.coli, H.pylori....etc.
The clear area around an antibiotic disc on agar where bacteria didn't grow is called:
What is the zone of inhibition?
When liquid cultures are incubated, what about the liquid symbolizes bacterial growth?
The liquid will appear cloudy
What can we do if a there are too many colonies to count (ie. the plate is too concentrated)?
We can dilute the original sample and then multiply the nuber of colonies by the dilution factor (aka how much we diluted the original sample by)
What is it called when we let out bacteria grow in 37 degrees for 16-24 hours?
Incubation