Lecture #7: Microbial Biology

Question 1

LO #1: 1. Define microbe. 2. Identify microbes on the tree of life.

Answer 1

1. microbe: microscopic organisms in any of the domains and viruses; includes all bacteria, archaea, and SOME eukaryotes.
2. just go look at the tree of life

Question 2

LO #2: provide examples of the importance of microbes to the ecosystem services and human society

Answer 2

• some bacteria are capable of fixing atmospheric N (essential for all life on earth)
• many are involved in the production of food (beer and bread)

Question 3

LO #3.1: define the great plate count anomaly

Answer 3

what we observe in the environment is greater than what we can actually grow as pure culture in lab

Question 4

LO #3.2: explain why pure cultures of microbes are not always possible (3)

Answer 4

• hard to replicate the environment (syntrophic interactions)
• hard to know the interactions b/w all species (coupled bichemical reactions)
• what can you even give them to survive if you don’t understand them

Question 5

LO #4: distinguish culture-independent DNA studies from the methods used by Carl Woese

Answer 5

• go directly into the environment and just sequence everything in the environment (PCR) while Carl Woese sequenced only the pure cultures he could keep alive in lab.

Question 6

LO #5.1: contrast the two-domains and three-domains hypotheses for relationships on the tree of life

Answer 6

two-domains: bacteria and archaea left alone, but eukaryotes are connected to archaea b/c some archaea are more closely related to eukaryotes

three domains: that life remains divided into the domains of B + A + E

Question 7

LO #5.2: explain the importance of Asgard Archaea

Answer 7

the importance of Asgard Archaea is that it has proven that using culture independent DNA studies allows us to explore rarely sampled habitats that reshaped our understanding of the Tree of Life

Question 8

microscopic life; includes all B, A, and some E

Answer 8

microbes

Question 9

sphere; singly or in plates, blocks, clusters

Answer 9

coccus (cocci)

Question 10

rod-shaped

Answer 10

rod (bacillus)

Question 11

helical or _____

Answer 11

spiral

Question 12

the 3 general morphologies of microbes

Answer 12

1. coccus
2. bacillus
3. helical

Question 13

all species are reliant on each other; where species rely on the metabolisms of other species

Answer 13

syntrophic communities

Question 14

ex of a syntrophic community

Answer 14

Winogradsky column

Question 15

is the growth of microorganisms in controlled environmental conditions

Answer 15

culturing

Question 16

the one which only one type of microbe is present

Answer 16

pure culture

Question 17

what we observe in the environment vs what we can actually grow in the lab

Answer 17

great plate count anomaly

Question 18

go directly into the environment and just sequence everything in the environment

Answer 18

culture-independent DNA studies

Question 19

culture-independent DNA studies: go into the 1. _________ and 2. _______ everything. Put all the data into a 3. ___ ____ with known and unknown. Compare to 4. ________ organisms. Make a 5. _______

Answer 19

1. environment
2. sequence
3. data matrix
4. existing
5. phylogeny