3) Bacteria Growth and Physiology

True or false

In nature bacteria divide asexually through binary fission and grow exponentially

False

They CAN grow exponentially but usually only due this a couple rounds because they run out of nutrients

-most bacteria live on surfaces as mixed communities

NAD+ is needed for glycolysis in bacteria. How is NAD replenished from NADH?

Through fermentation.

Pyruvate is reduced lactic acid while NADH is oxidized to NAD

In anaerobic respiration certain bacteria can use what 3 other ions besides oxygen as the final electron acceptor?

-Nitrate (NO3-)

-Sulfate (SO4^2-)

-Carbonate (CO3^2-)

What are the 3 basic types of bacteria based on their relationship with oxygen? What category contains the most?

Facultative anaerobic: can grow in the presence of absence

-most bacteria (that we discuss)

Obligate anaerobe: cannot tolerate oxygen

-oral and gut

Strictly aerobic: only grow in presence of oxygen

-few

What bacteria is unique in that is lacks peptidoglycan?

Genus Mycoplasma

-causes pneumonia and contribute to pelvic inflammatory disease

What are 3 genus that are part of the 'odd' group "intracellular bacteria"? What is unique about this group?

-Genus Mycoplasma

-Genus Chlamydiae

-Genus Rickettsiae

only live inside the host cell. Cannot make ATP on its own and have very HIGH nutritional requirements

Know how to do a doubling time problem

Example: doubling time is 30 minutes. Starting with 2 cells what is the total after 2 hours?

2 hours / 30 minutes = 4

30 minutes: 2x2 = 4

1 hour: 4x2 = 8

1 hour 30 minutes: 8x2 = 16

2 hours: 16x2 = 32

What are the 4 growth phases of bacteria?

1. Lag

2. Log / Exponential

3. Stationary (this is when virulence factors are expressed and most resistant)

4. Decline phase (varies)

In Nathalie Balaban there were populations that survived after antibiotic treatment. What where they called? Why did they survive?

Persisters

-non growing and non dividing cells live

-antibiotics only attached those actively dividing

-which is why some antibiotic treatments must be taken for the entire time so all bacteria can be killed

What is sporulation?

Does it occur in gram positive, negative, or both?

How can they be killed?

-symmetric cell division

-Alternative to binary fission when nutrients become limited, in the stationary phase, or environment is stressful

-gram positive

-resistant to solar radiation! must be killed with chlorine bleach or steam autoclave

-cannot disinfect with ethanol

How do you test bacteria for motility?

soft agar "stab" and migration of visible growth through the media

-We can stab/punch the agar containing bacteria and if we see the bacteria spreading from this puncture line - that means the bacteria are motile and have flagella.

True or False

Fermentation can be used to identify bacteria

true

When give Mannitol will turn yellow will produce sugar

fermentation of sugars changes pH of the media the bacteria are grown in (in the lab).

This can cause a color change of the media if we use an indicator.

Spores can only grow on gram positive. What genus are most often associated with them in studies? What is their type of oxygen requirement?

- Genus Bacillus (strict aerobes)

- Clostridium (anaerobes)

*remember MHC presentation is better when there is protein conjugation

-antigen presenting cells better to t cells