Name: ______________________________ Date: ____________________ Period: _______ Pg. #: ______
Understanding Bacteria Video
Answer the following questions to the best of YOUR ability. We will go over them
together at the end of the video.
Part 1:
1. What is the greatest cause of human death and illness?
Infectious Disease/Currently 3rd highest in US
2. What percent of bacteria actually cause disease?
Less than 1%
3. How does life on Earth depend on bacteria?
Food Production
Enzymes-Cleaning
Digesting Food
Decomposing/Recycling
Produces Oxygen
4. How do bacteria reproduce? How long does it take a typical bacterium to go
through the cell cycle?
They split in two…Binary Fission
It takes approximately 20 minutes
5. How do E. coli bacteria aid us in digestion?
Turn food into sugars and processes vitamins.
Occupy spaces that harmful bacteria may try to occupy
6. How can the deadly toxin produced by the bacterium Clostridia botulina be
beneficial in medicine?
Tiny amount of toxin (1/1000th of the lethal dose) relaxes overactive muscles and
helps people with muscle spasms. Possible use in future for MS, Parkinson’s, etc.
7. What gives sourdough bread its sour taste?
Unique strain of lactobacilli bacteria
8. How does bacteria help in the making of different foods? What foods do they
help make?
Cheese, bread, milk (in cows, it converts food into nutrients). In cheese, bacteria
eats nutrients and makes a gas which the cheese flavor and add holes.
9. How does someone get ill from a bad strain of E. coli? Where do the bad
strains come from?
Eating undercooked beef. The strains are in the intestines of cows. So when
ground cow meat is not cleaned properly, anyone who eats the meat can be
infected.
10. What accidental discovery in microbiology changed medical history in the
20th century?
A mold (penicillium) killed bacteria. Flemming discovered this in Petri dishes
that he failed to clean before he left for vacation
11. How do bacteria change and become resistant to antibiotics?
When bacteria reproduce sexually and exchange DNA (conjugation). Bacteria that
are drug resistant can pass these genes onto non-resistant bacteria.
Part 2:
1. What practices in society have promoted the development of antibiotic
resistant bacteria?
Use of antibiotics in animal feed, sprayed on fruits and vegetables, excessive
prescriptions of antibiotics, patients who need antibiotics, but don’t take the entire
prescription.
2. What are the possible consequences of widespread application of antibiotics?
We might create antibiotic resistant organisms making antibiotics less effective in
treating disease.
3. In Lead, South Dakota, how did bacteria help to clean up the ‘black’ creak
created by the Homestake Mining Company?
Bacteria ate the cyanide as their food source.
4. Why are bacteria considered to be highly evolved?
They reproduce efficiently and have adapted to live in very hostile environments.
5. What method is used to study bacteria that cannot be cultured in a
laboratory?
Extracting genes from bacteria directly from the soil.