Ch 10 and 11: Prokaryotes

Question 1

Classification of prokaryotes

Answer 1

• 3 domains → Eukarya, Archaea, & Bacteria
• Domains are divided into phyla, which are divided into classes, etc.

Question 2

Archaea: the most primitive organisms on earth

Answer 2

• Lack peptidoglycan
• are extreme thermophiles (high heat)
• extreme halophiles (high salt)
• extreme acidophiles (ow pH)
• Methanogens –> produce methane (anaerobic)

Question 3

Bacteria ID

Answer 3

• gram + or gram -
• first step is gram stain but need to do more tests

Question 4

Biochemical tests

Answer 4

• Looks at enzyme activity
• Limitations: mutations/plasmids; requires culturing which takes time
• Selective and differential media
• Can look at multiple ID tests at once
• quick and efficient but can get false results

Question 5

Serological tests

Answer 5

• Look at blood serum (blood without clotting factors) and see what antibodies are present
• Rapid detection antigen tests → such as strep testing
• In-vivo tests → inside a living thing; TB test

Question 6

ELISA (Enzyme-linked immunosorbent assay)

Answer 6

• Fast and efficient
• Look for color change
• Ex: Covid test, pregnancy test, AIDS testing

Question 7

PCR (polymerase chain reaction)

Answer 7

• Allows you to make a lot of copies of a particular DNA sequence in a short amount of time
• Need to include primers → short pieces of DNA that tell DNA polymerase to start copying
• Put everything in tube, heat it up to a super high temp
  (Temp: separate DNA strands because helicase is expensive
  Then cool it down so that the primers can attach)
• Done in labs: early covid testing

Question 8

Dichotomous key

Answer 8

• guess who
• Series of successive questions with 2 possible answers

Question 9

Prokaryotic Classification: 2 main guides

Answer 9

Determinative Bacteriology:
- Shows phenotypic characteristics
- Classical ways of ID microbes
- Not published since 1995
Systematic Bacteriology:
- A much more extensive classification scheme
- Based on DNA and RNA sequences