L6 - Sporulation

Question 1

What are spores?

Answer 1

metabolically dormant, stress resistant and poised for germination when conditions are right

Question 2

what is the strucutre of a spore and how does it contribute to its function

Answer 2

have specialised, multi-layer surface structures and unique composition

Question 3

what kind of proteins do spores contain?

Answer 3

proteins for stress resistance, anabolism and cell signalling

Question 4

When do spores germinate in a population

Answer 4

spores germinate with heterogeneity, same population will not germinate at the same time. they stagger its germination over hours to days

Question 5

roles of spores

Answer 5

• survive in response to adverse growth conditions (can survive heat etc)
• used to disperse organisms to new environments
• used as reproductive strategy

Question 6

3 different sort of endospore location

Answer 6

1. terminal spores = formed at the poles
2. sub terminal spores = near the pole but not at the pole (bacillus)
3. central spores = formed in the middle of the bacterium

Question 7

What are the characteristics of bacillus subtilis

Answer 7

rod shape, gram positive, motility when under stress

Question 8

Sporulation in B.subtilis

Answer 8

• when lack of nutrient and high cell density
• only occurs in subpopulation
• irreversible
• last resort for cell survival

Question 9

Describe the structure of a spore from B. subtilis

Answer 9

outer coat, inner coat, outer membrane, cortex, inner membrane, core, compacted chromosomal DNA

Question 10

Lifecycle of B. subtilis when sporulation happens

Answer 10

1. when there is a high cell density and a lack of nutrients, the bacteria undergoes asymmetric cell division that separates the forespore from mother cell
2. mother cells engulf the forespore within its membrane and starts synthesising its coat and cortex
3. spores mature and mother cell releases spore into the environment

Question 11

steps in sporulation:

Answer 11

1. 2 chromosomes
2. chromosome condensation
3. polar septum formation
4. engulfment
5. cortex and coat assembly done by mother cell
6. spore maturation chromosome condensation
7. mother cell lyse

Question 12

details of DNA translocation during foreshore formation

Answer 12

1. must be 2 full chromosomes for sporulation to start
2. origins tethered at opposite poles
3. 30% of the DNA is in the forespore
4. active translocation of the rest of the chromosome in the foreshore