Lecture 29

Question 1

why are prokaryotes so dominant?

Answer 1

fast growth rate, evolve quickly

Question 2

what are the steps of binary fission?

Answer 2

• chromosome replication begins
• one copy on each side
• replication finishes
• two daughter cells result

Question 3

what are the differences between eukaryotes and prokaryotes for cellular requirements?

Answer 3

same components, different amounts

Question 4

what is a closed batch culture system?

Answer 4

• form of culturing
• limited amount of nutrients provided
• once used, cells can’t proliferate/multiply
• standard method

Question 5

what are the phases of microbial growth?

Answer 5

• Lag Phase = length depends on history of the inoculum, time is required to get biosynthetic reactions running
• Exponential Phase (log phase) = cells are actively dividing and nothing is limiting for growth. Population is doubling in
  a constant time interval (under ideal conditions)
• Stationary Phase = cells stop growing and cryptic growth is observed
• Death phase = cell death. Equilibrium between growing cells and dying cells is skewed towards death.

Question 6

what is cryptic growth?

Answer 6

organisms survive by consuming lysed cell constituents of other dead cells within the culture

Question 7

what do prokaryotes need for replication?

Answer 7

• carbon source
• energy source
• reducing power

Question 8

how is energy harvested by prokaryotes?

Answer 8

• Chemical energy stored in bonds
• Broken chemical bonds release energy that can be captured in new bonds (ATP)
• ATP bonds can be broken again later to release that energy

Question 9

whats the difference between catabolism and anabolism?

Answer 9

catabolism = energy generation
anabolism = energy consumption

Question 10

what is a photoautotroph?

Answer 10

• light for energy source
• CO2 carbon source

Question 11

what is a chemoheterotroph?

Answer 11

• chemical compound energy source
• organic compounds for carbon source

Question 12

what is a photoheterotroph?

Answer 12

• light for energy source
• organic compounds for carbon source

Question 13

what is a chemoautotroph?

Answer 13

• chemical compound energy source
• CO2 carbon source

Question 14

what is an auxotroph?

Answer 14

organism that is unable to synthesize one or more essential growth factors, and it will not grow unless factor is provided

Question 15

what is cross-feeding?

Answer 15

one species gains metabolic
products of another species

Question 16

what is a microbiome?

Answer 16

complete collection of microorganisms, and their genes, within a particular environment

Question 17

What is a microbiota?

Answer 17

Individual microbial species in a biome – bacteria, fungi, archaea and viruses

Question 18

what are culture dependant methods?

Answer 18

• Relies on culturing of microbes in the lab
• Uses pure cultures, or simple (reduced diversity) enrichments

Question 19

what are the benefits of using culture dependant methods?

Answer 19

• Allows access to phenotype
• Can study one organism at a time
• Can manipulate conditions to see response of organism

Question 20

what are the cons of using culture dependant methods?

Answer 20

• Not all organisms can be cultured
• Too many species to grow them all
• Culturing requires precise conditions to match microbes needs
• Does not match real world conditions

Question 21

what are culture independent methods?

Answer 21

• Relies predominantly on nucleic acid-based methods. No
  culturing required.
• Uses sequencing or metabolic profiling to study all microbes
  in a sample

Question 22

what are the benefits of culture independent methods?

Answer 22

• Allows access to genotype
• Can study many organisms at a time
• Shows communities as they are in nature
• Can target non-culturable organisms
• Provides access to unknown information/species

Question 23

what are the cons of culture independent methods?

Answer 23

• No pure culture, so no ability to manipulate
• Expensive and complex methods