Microbial Diversity, Earth's History

Question 1

How old is Earth?

Answer 1

4.6 billion years old

Question 2

What was the composition of the anoxic atmosphere during early Earth’s history?

Answer 2

Mostly N2 and CO2

Question 3

What type of metabolism did the first microbial cells use?

Answer 3

Anaerobic metabolism

Question 4

What was the state of water on Earth from 4.5 to 4.3 billion years ago?

Answer 4

Water was gaseous

Question 5

What formed instead of O2 by early phototropic organisms?

Answer 5

Sulphur

Question 6

When did archaea devolve from a common ancestor of bacteria?

Answer 6

3.5 billion years ago

Question 7

When did the first stromatolites appear?

Answer 7

3.5 billion years ago

Question 8

What significant evolutionary event occurred 2.8 billion years ago?

Answer 8

Cyanobacteria evolved with the ability to carry out oxygenic photosynthesis

Question 9

What happened 2.4 billion years ago in relation to Earth’s atmosphere?

Answer 9

Effects of oxygenated atmosphere began to be seen

Question 10

What is the oxygen revolution?

Answer 10

When all ferric ions were converted and O2 levels began to rise

Question 11

What are acritarchs?

Answer 11

Earliest eukaryotic fossils

Question 12

What is the main resource for determining the identity of prokaryotic organisms?

Answer 12

Bergey’s Manual of Determinative/Systematic Bacteriology

Question 13

What are the two main types of analysis used to identify species of Bacteria and Archaea?

Answer 13

Phenotypic analysis
Genotypic analysis

Question 14

What does the phylogenetic species concept require from species members?

Answer 14

Genetically and phenotypically cohesive
Distinct traits from other species
Monophyletic

Question 15

Define paraphyletic group.

Answer 15

Includes the common ancestor and some, but not all, of the ancestor’s descendants

Question 16

Define polyphyletic group.

Answer 16

Does not include common ancestor of the group

Question 17

Define monophyletic group.

Answer 17

Includes common ancestor and all descendants of the ancestor

Question 18

What is catabolism?

Answer 18

The breakdown of molecules to generate energy

Question 19

What type of organisms are chemoorganotrophs?

Answer 19

Organisms that use organic chemicals for energy

Question 20

What type of energy do phototrophs use?

Answer 20

Light energy

Question 21

What is the difference between heterotrophs and autotrophs?

Answer 21

Heterotrophs: require one or more organic compounds
Autotrophs: use CO2

Question 22

What does OIL RIG stand for?

Answer 22

Oxidation Is Loss of electrons, Reduction Is Gain of electrons

Question 23

Give an example of an oxygenic photosynthetic bacterium.

Answer 23

Cyanobacteria

Question 24

What do anoxygenic photosynthetic bacteria use for energy?

Answer 24

H2S as an electron donor

Question 25

What is the role of dissociative sulfate-reducing bacteria?

Answer 25

Use H2 as electron source and reduce SO42- to H2S

Question 26

What is the significance of the 16S gene in bacterial classification?

Answer 26

Contains variable regions used for taxonomic assignment

Question 27

What does a 97% similarity in single gene analysis indicate?

Answer 27

Same species

Question 28

What is the typical GC content range in prokaryotes?

Answer 28

25-80%

Question 29

What is the importance of porins?

Answer 29

Anion channel, voltage dependent

Question 30

What is cardiolipin's role?

Answer 30

Important in regulation of proteins

Question 31

What is the main difference between single gene analysis and multi-gene analysis?

Answer 31

Single gene focuses on one gene, while multi-gene analyzes multiple genes