Virus and Prokaryotes

Question 1

Size of viruses ?

Answer 1

T4 phage < pandovirus (10x bigger)

Question 2

Virus’s role in ecology ?

Answer 2

HUGE carbon sink

Question 3

Which feature of bacteria is most informative for reconstructing their phylogeny?

Answer 3

mRNA

Question 4

How do most bacteria reproduce?

Answer 4

1. binary fission (budding)
2. intracellular offspring (bud engulfed by cell and leaves)
3. endospore (bud became super resistance)

Question 5

Bacteria have what type of DNA and cell wall ?

Answer 5

• circular dna
• peptidoglycan cell wall (mesh)

Question 6

Virus origin theories (3)?

Answer 6

1. virus 1st (before cells)
2. regressive (degenerate eukaryotic cells)
3. progressive (escape from proto-cells) - virus world
   - cooperative genes became
   cell genome
   - parasitic genes became
   viruses

Question 7

Gram positive vs Gram negative ?

Answer 7

Positive:
- 1 membrane
- thick
- purple

Negative:
- 2 membranes (more resistance to antibiotics)
- thin
- pink

Question 8

Genetic recombination in bacteria (3) ? sex ?

Answer 8

• lateral gene transfer: pick up dna pieces from diff organisms in environment
• conjugation: join others from same species and exchange dna pieces
• transduction: transfer of dna pieces by virus infecting and tricking

NOT SEX

Question 9

Bacterial shapes ?

Answer 9

1. sphere/coccus
2. rod/bacillus
3. corkscrew/spirillum

Question 10

What is multicellularity? Are there multicellular bacteria?

Answer 10

• single species, division of labor, some give up reproduction
• yes, proteo- and actibobacteria (big, antibiotics)

Question 11

What is a biofilm? Is it multicellular? What are the advantages of being in a biofilm as opposed to being free-living?

Answer 11

• mixed species
• ## yes

Question 12

Contrast the phylogeny of “Uprooting the tree of life?” with the conventional tree

Answer 12

conventional tree of life: hierarchical structure with clear branching patterns based on vertical descents

• “Uprooting the Tree of Life” hypothesis: suggests complex network-like structure where horizontal gene transfer blurs traditional evolutionary relationships, particularly among microbial organisms.

Question 13

When the energy source is light, what suffix is associated with it ?

Answer 13

photo-

Question 14

When the energy source is chemical, what suffix is associated with it ?

Answer 14

chemo-

Question 15

When the electron source is inorganic, what suffix is associated with it ?

Answer 15

Litho-

Question 16

When the electron source is organic, what suffix is associated with it ?

Answer 16

Organo-

Question 17

When the carbon source is from CO2, what suffix is associated with it ?

Answer 17

Auto-

Question 18

When the carbon source is from organics, what suffix is associated with it ?

Answer 18

Hetero-

Question 19

how do bacteria affect the biosphere ?

Answer 19

• add or fix nitrogen to soil
• oxygen !!
• mass extinction because of toxic O2)

Question 20

Are most bacteria pathogenic? If so, how do bacterial pathogens enter host cells?

Answer 20

• some
• trick cell to invite it in (endocytosis), hide in ER, turn off MHC immunity

Question 21

in terms of cell structure and function, and ecology, how are archaea similar to, and
different from, bacteria?

Answer 21

• similar in morphology
• different: in gene expression and cell ultrastructure
  - membrane (left handed !!
  goes up)
  - cell wall, (crystal protein/s-
  layer)
  - flagella (diff motor)

Question 22

What has the new (2016) phylogeny told us about bacterial and archaeal diversity (do we know most of it?) and phylogeny (might one of the domains be non-monophyletic?)

Answer 22

• greater diversity
• archaea might be non-monophyletic