2.3

Question 1

What are the key components within bacterial cytosol?

Answer 1

ribosomes
granules
endospores
nucleoid
plasmids

Question 2

What are ribosomes?

Answer 2

composed of rRNA and proteins and made up of large and small subunits
- key player in translation (coupled in prokaryotes)
- 50s + 30s = 70s for prokaryotes
- 60s + 40s = 80s for eukaryotes
- S = svedburg unit or sediment rate (size and shape)
can develop medicine to attack ribosomes

Question 3

What are granules?

Answer 3

storage bodies/inclusion bodies
- stores synthesized or obtained nutrients/metabolites as well as by-products of metabolic activitiy
- includes specialize granules for sugars, fats and phosphates

Question 4

What are endospores?

Answer 4

produced under threatening environmental conditions
- known as sporulation
Purpose is to protect
- resistant to harsh conditions
- no reproductive capability when in endospore form, but can exist for many years

Question 5

bacillus spp. (B. anthracis & B. cereus)

Answer 5

can form endospore

Question 6

clostridium spp. (C. tetani, C. perfringens, C. botulinum, & C. difficile)

Answer 6

can form endospore

Question 7

Endospore structure

Answer 7

core: DNA, ribosomes, granules
cell wall: normal gram-positive peptidoglycan
cortex: thick layer of loosely cross-linked peptidoglycan
spore coat: highly cross-linked keratin proteins as well as other structural proteins
exosporium: not always present, varies in composition (primarily proteins and carbohydrates)

Question 8

endospore formation

Answer 8

1. vegetative cell begins to be depleted of nutrients
2. chromosome is duplicated and separated
3. The cell is septated into a sporangium and forespore
4. sporangium engulfs forespore for further development
5. sporangium begins to actively synthesize spore layers around forespore
6. cortex and out coat layers are deposited
7. mature endospore
8. free spore is released with the loss of the sporangium
9. germination: spore swell and releases vegetative cell

Question 9

What is a nucleoid?

Answer 9

Region of dense genomic DNA (circular chromosome)
- origin of replication is often associated with the cell membrane
- chromosome is condensed via DNA gyrase/topoisomerase supercoiling
- scaffolding proteins can assist in condensing the chromosome as well

Question 10

What is the CRISPR/Cas system?

Answer 10

Bacterial immune system: will destroy viral genomic material the bacterium has previously encountered
CRISPR
- clustered regularly interspaced short palindromic repeats
- family of DNA sequences within prokaryotic genomes
- flanked by viral DNA from previous infections
CAS
- CRISPR-associated genes/proteins
- DNA endonuclease
- uses cRNA and guide RNA to target specific complementary DNA sequences

Question 11

What are plasmids?

Answer 11

small circular pieces of DNA
- contain non-essential genes, advantageous
classification based on characteristics
engineered plasmids: synthetically made or modified by scientists

Question 12

define colicins (Col) plasmids

Answer 12

code for bacteriocins

Question 13

define degradative plasmids

Answer 13

code for digestive enzymes

Question 14

define fertility (F) plasmids

Answer 14

code for conjugation genes

Question 15

define virulence plasmids

Answer 15

code for genes important for pathogenicity (PAI: pathogenicity island)

Question 16

define resistance (R) plasmids

Answer 16

code for resistance to antibiotics or other toxic chemicals