Topic 2-L8 - Bacterial cells - Cell inclusions-endospores

Question 1

Prokaryotic cells can contain “inclusions” :

Answer 1

bodies or aggregates within the cell

Question 2

Related, bacterial cells can also have “microcompartments” :

Answer 2

protein shells than encase specific enzymes/metabolites/cofactors that carry out specific metabolism

Question 3

Diverse prokaryotes store carbon as lipids known as poly-β hydroxyalkanoates (PHA), the most common of which is

Answer 3

poly-β- hydroxybutyric acid (PHB)

Question 4

PHA is a polymer that’s produced when

Answer 4

there is an excess of carbon/energy - aggregates and forms large granules

Question 5

Inorganic phosphate in polyphosphate granules

Answer 5

(excess of phosphate – broken down to produce nucleic acids phospholipids)

Question 6

Sulfur storage granules produced by bacteria (and archaea) that

Answer 6

oxidize reduced sulfur compounds for energy/CO2 fixation

Question 7

Some bacteria/archaea can float because they produce

Answer 7

gas vesicles

Question 8

gas vesicles functions

Answer 8

• keep water/solutes out and gas in

- bouncy : bring microbes to favourable environments

Question 9

Example of gas vesicles in Bactria

Answer 9

Cyanobacteria

Question 10

Some bacteria produce microcompartments –

Answer 10

polyhedral protein shells that encase specific enzymes/metabolites/cofactors

Question 11

Carboxysomes (type of micro compartment) –

Answer 11

concentrate enzymes involved in carbon fixation – increases efficiency and reduces unwanted side reactions

Question 12

Other microcompartments protect cell against

Answer 12

toxic/reactive intermediates/bi products

Question 13

Endospores are highly differentiated,

Answer 13

dormant cells that can survive starvation and very harsh environmental conditions

Question 14

endospores only produced by certain members of the

Answer 14

phylum Firmicutes (Bacillales, Clostridiales) – Gram positive.

• more resistant

Question 15

Vegetative cells (endoscopes)

Answer 15

(normal, metabolically active, growing/dividing cells) differentiate into endospores upon nutrient deprivation

Question 16

When the environment becomes more favorable, the spore can be

Answer 16

activated, germinate and return to the vegetative state

Question 17

Creating a stable and resistant core

Answer 17

• dehydration of the core
• Dipicolinic acid (DPA)
• Small acid soluble proteins (SASPs)

Question 18

Dehydration of the core is key -

Answer 18

increases dessication, heat, chemical resistance – inactivates (without denaturing) cell’s enzymes

Question 19

Dipicolinic acid (DPA) – unique to spores. Is complexed with

Answer 19

Ca2+ (up to 10% of spore weight). Important for dehydration process, also binds/stabilizes DNA

Question 20

Small acid soluble proteins (SASPs) only made during sporulation.

Answer 20

Bind DNA – help make it more compact, protect it from damage (UV, heat, denaturation, mutation). Also act as carbon/energy source during germination/outgrowth

Question 21

Endospores - structure

Answer 21

• core
• cortex
• two membranes
• coat

Question 22

Core is where

Answer 22

DNA/ribosomes are housed – will become the vegetative cell

Question 23

Cortex

Answer 23

peptidoglycan layer

Question 24

Two membranes

Answer 24

this “outer membrane” nothing like Gram negative OM – no LPS

Question 25

Coat –

Answer 25

protective protein layer comprised of many different proteins

Question 26

Some spores produce a second protein layer called the ___________

Answer 26

exosporium

Question 27

Major events in Endospore formation

Answer 27

1) asymmetric cell division : commitment to sporulation septum formation
2) engulfment : (outer spore memb. Formed)
3) late sporulation: form coat and coat
4) maturation: dehydration of spore, Ca uptake
5) mother cell lysis