Topic M. Succeeding in the Environment

Question 1

What are the components of a bacterial two-component system?

Answer 1

1. sensory kinase (senses stress)
2. response regulator (transduces signal)

Question 2

How does the two-component system ensure bacterial survival?

Answer 2

It sense stress, activates the response regulator, and allows bacteria to adapt to external conditions

Question 3

What powers bacterial swimming and swarming motility?

Answer 3

1. swimming = flagella
2. swarming = flagella or pili

Question 4

What is twitching motility, and how is it powered?

Answer 4

twitching is powered by pili where the pilus extends, attaches, and retract, pulling the bacteria

Question 5

How do stationary-phase cells differ from exponential-phase cells in terms of size and structure?

Answer 5

stationary phase cells are smaller, rounder, and more tightly packed

Question 6

What happens to protein synthesis in stationary-phase cells?

Answer 6

protein synthesis is reduced, and protease activity increases to recycle resources

Question 7

What is the function of sigma factors in bacterial cells?

Answer 7

sigma factors recruit RNA polymerase to specific promoters, controlling gene expression

Question 8

How do different sigma factors ensure proper regulation of genes?

Answer 8

they compete for limited amounts of RNA polymerase and are activated under different environmental conditions

Question 9

What are the key stages in biofilm formation?

Answer 9

1. attachment (reversible)
2. attachment (irreversible) –> lose flagella
3. cell division
4. secretion of expolymeric substances
5. dispersal

Question 10

What bacterial process in biofilm formation could be targeted by antibacterial drugs?

Answer 10

1. quorum sensing
2. flagella
3. exopolymeric substance production

Question 11

What signal triggers the start of sporulation in bacteria?

Answer 11

pro-sporulation signal = Spo0A-P

Question 12

What are the major stages of endospore development?

Answer 12

0. entry into sporulation (axial filament formation)
1. polar separation (forespore + spore mother cell)
2. engulfment
3. cortex formation
4. coat formation
5. release

Question 13

What features make endospores so touch and resistant to harsh conditions?

Answer 13

their structure which includes a core, cortex, spore coat layers, and exosporium which protects against heat, radiation, and chemicals

Question 14

Why are endospore-forming bacteria a challenge in clinical settings?

Answer 14

they can survive harsh conditions and persist in hospital environments leading to difficult to eradicate infections