2-7: Bacterial Cell Inclusions and Endospores

Question 1

What is an inclusion

Answer 1

Body or aggregate within cell, often related to storage

Question 2

What is a microcompartment

Answer 2

Protein shells that encase specific enzymes/metabolites, cofactors

Question 3

What are carbon storage polymers

Answer 3

Lipid polymers produced when there is excess carbon/energy. They aggretate to form large granules and are broken down when energy is needed

Question 4

What is the name of the carbon storage polymer lipid used?

Answer 4

poly-beta-hydroxyalkanoates (PHA), the most common of which is poly-beta-hydroxybutryric acid (PHB)

Question 5

Where is inorganic phosphate stored

Answer 5

Polyphosphate granules; broken down to produce nucleic acids, phospholipids

Question 6

Where is excess sulfur stored

Answer 6

Sulfur storage granules

Question 7

What organisms produce sulfure stoarge granules?

Answer 7

Made by bacteria/archaea that oxidize reduced sulfur compounds for energy

Question 8

What are gas vesicles. eg?

Answer 8

Protein structures that keep water/solutes out, let gas in. Confer buoyancy - can bring microbe to favourable environment. e.g. cyanobacteria at surface of water = sunlight

Question 9

What are microcomparments? Give an example.

Answer 9

Polyhedral protein shells that encase specific enzymes/metabolites/cofactors. eg. carboxyzomes

Question 10

What are carboxysomes

Answer 10

Microcompartments that concentrate enzymes involved in carbon fixation. Leads to increased efficiency, reduces side reactions

Question 11

What are some functions of microcompartments?

Answer 11

Protect the cell from toxic metabolites

Question 12

What is an endospore

Answer 12

Hihgly differentiated dormant cell that survives starvation, harsh evironment

Question 13

What phylum produces endospores

Answer 13

Firmicutes (gram +)

Question 14

Are endospores the only kind of spore?

Answer 14

NO, diff bacteria create diff spore structures

Question 15

What are endospores resistant to

Answer 15

Heat, radiation, drying, nutrient depletion, chemicals, etc

Question 16

What is a vegetative cell

Answer 16

A metabolically active, growing/diving cell that become endospores upon nutrient deprivation. Can be reactivated/germinate when environment becomes favourable

Question 17

Name four metabolic changes that occur when a cell changes from vegetative to endospore

Answer 17

Low to high Ca2+, generation of ipicolonic acid, decrease water content, generation of SASPs

Question 18

How do endospores create a stable/resistant core

Answer 18

Dehydration of the core, Dipicolinic acid, Small acid soluble proteins

Question 19

What is dehydration of the core

Answer 19

Water from 80% to <25%. Increases resistance to dessication, inactivates enzymes

Question 20

How do dipicolinic acids help endospores

Answer 20

Complexed with Ca2+. Important in dehydration process, binds/stabilizes DNA

Question 21

How do small acid soluble proteins help endospores

Answer 21

only made during sporulation. Bind DNA - make it compact, protect it from damage (UV, heat denaturation). Act as carbon/energy source during germination

Question 22

What are the structures of the endospore

Answer 22

Core, cortex, two membranes, coat, and exosporium

Question 23

What is the core of an endospore?

Answer 23

Where the DNA/ribosomes are held - will become the vegetative cell

Question 24

What is the cortex of an endospore?

Answer 24

Peptidoglycan layer

Question 25

What are the two membranes of an endospore?

Answer 25

Contains an outer membrane with NO LPS (nothing like gram negative)

Question 26

What is the coat of an endospore?

Answer 26

Protective protein layer with lots of different proteins

Question 27

What is the exosporium?

Answer 27

A second protein layer present in some endospores