2.7 Bacterial Cells Flashcards
1
Q
What are inclusions and what types of cells have them?
A
- Prokaryotic cell has them
-inclusions aggregate in cells and are often related to the storage of a substance.
2
Q
What are microcompartments and who has them?
A
-bacterial cells
- protein shells that encase specific enzymes, metabolites, and cofactors, that carry out specific metabolism.
3
Q
What are the three things Carbon inclusions allow for?
A
- Carbon storage (PHB)
- P, S, Carbonate storage (carbonate permits biomineralization)
- Gas Vesicle
4
Q
what is carbon storage (PHB)?
A
- basically when bacteria stores carbon when times are good, to be accessed during periods of starvation.
- prokaryotes store carbon as lipids called poly-beta-hydrooxyalkanoates (PHA), the most common is poly-beta hydroxybutyric acid (PHB)
- the PHB polymer is produced when there is an excess of carbon, it aggregates and forms large vacuoles.
- theses polymers are then broken down for carbon and energy when needed.
5
Q
What is polyphosphate and sulfur carbonate storage?
A
- inorganic phosphate is stored in polyphosphate granules (excess phosphate). This then is broken down to produce nucleic acids and phospholipids.
- sulphur storage granules produced by bacteria (and archaea) that oxidize reduced sulphur compounds for energy.
a. used energy to fuel metabolism
6
Q
what is gas vesicles?
A
- in gas vesicles bacteria and archaea can float since they produce gas vesicles.
- these are basically structures that keep water and solutes out but allow only gas in
- This keeps them a property of buoyancy, which brings these microbes to a favourable environment. (ex. water wings)
-ex. cyanobacteria blooms at the surface of the water which allows for more sunlight, and efficient photosynthesis.
7
Q
What are micro-compartments?
A
- they are polyhedral protein shells that encase specific enzymes, metabolites and cofactors.
- it is used to protect against toxic intermediates, reactive intermediates and byproducts.
8
Q
what are carboxysomes?
A
- they are concentrate enzymes involved in carbon fixation.
- they help in crease the efficiency and reduce unwanted side reactions.
- oxygen will compete with co2
9
Q
Modification of Endoscopes
A
- highly retractile and thick-walled structures formed inside the bacterial cells
- they are highly differentiated, are sleeping cells that can survive starvation and very harsh environmental conditions.
a. can have a microbial cell change to a different lifestyle. - they are only produced by Firmicutes (gram positive) –> much more resistant than others.
10
Q
what are endospores resistant to?
A
- they are resistant to extreme heat, radiation, drying, nutrition depletion, and chemicals.
- they can long years –> germinate –> grow again.
11
Q
What is an analogy of Endospores?
A
- it is basically like freezing your self and preserving your self without any technology.
12
Q
what are endospores? what kind of cells are they?
A
- They are vegetative cells that differentiate into endospores upon nutrition deprivation (starvation)
a. they are metabolically active, growing and dividing cells. - they are usually activated when the environment becomes favourable, the spore can be activated, germinate and return to a vegetative state.
13
Q
what are the two features of endospores?
A
- They need to shut off metabolism, cell activities
- Provide resistance and stability.
i) has a program that protects you
form UV light for example.
14
Q
What is the key for creating a stable and resistant core?
A
- Dehydration of the core is KEY.
a. the water goes from greater than 80% of water (vegetative cell) to less than 25% of water (dehydrated cell) - Dehydration helps increase the resistance to the removal of moisture, heat, and chemicals. it inactive cells enzymes via denaturation.
15
Q
What is Dipicolinic Acid (DPA)?
A
- unique characteristics of a spore.
- it is complex with ca2+
- important for dehydration processes. and binds/stabilizes DNA.
a. if you loose DNA –> game over = important to stabilize DNA
16
Q
What is Small acid-soluble proteins (SAPSs)?
A
- they are only made during sporulation.
- Bind DNA and make it more compact and protect it from damage.
- they also act as carbon energy sources during germination and outgrowth.
17
Q
Endospore strutcure
A
- Let’s start from inner to outer
- DNA
2. core
3. inner membrane.
4. cortex
5. outer spore membrane
6. endospore coat
7. exosporium
- DNA
18
Q
what is core?
A
- where DNA and ribosomes are found, it will become a vegetative cell.
19
Q
what is a cortex?
A
peptidoglycan layer that is chemically modified to be more flexible.
20
Q
What is the Inner and Outer Membrane?
A
- outer layer is for extra protection, but nothing like Gram-negative OM, no LPS
21
Q
what is the coat?
A
- is the protective layer comprised of different proteins. each of the different proteins have different roles.
22
Q
what is the exosporium?
A
- many spores produce a second protein layer.
- it is on top of the coat layer for extra protection.
23
Q
Major events in endospore formation?
A
- vegetative cell begins to be depleted of nutrients.
- The chromosome is duplicated and separated.
- The cell is separated (division of cavity in parts)
- sporangium engulfs the forespore for further development.
- sporangium begins to actively synthesize spore layers around the forespore. (early spore)
- The cortex and outer layers are deposited.
- mature endospore
8 . free spore is released with the loss of sporangium. - germination: spore swells and releases vegetative cells.
OR
- vegetative cell begins to be depleted of nutrients.
- Asymmetric cell division; commitment to sporulation septum formation.
- engulfment: outer space membrane formed.
- Late sporulation; cortex and spore coat formed.
- Maturation: dehydration of spore, Ca2+ uptake, SASPs, picolinic acid.
- Mother cell lysis.
- Free spore releases
- Germination.
