prokaryote ecology

Question 1

liebig’s law of the minimum

Answer 1

the amount of growth of any organism depends on which of its required nutrients has the lowest concentration (which it will run out of first)

Question 2

shelford’s law of tolerance

Answer 2

for an organism to grow in a given environment, each of a complex set of conditions must remain within the tolerance range of that organism

Question 3

the great plate count anomaly

Answer 3

total counts yield higher results than viable counts; with typically less than 1% of the total count can be cultured (explanations → cell death + incorrect growth conditions)

Question 4

facultative anaerobes

Answer 4

don’t need oxygen, but it doesn’t bother them to have it

Question 5

aerotolerant anaerobes

Answer 5

only use fermentation for ATP process, but produce enzymes to protect from harmful oxygen effects

Question 6

extremophiles definition

Answer 6

live in extreme conditions (of temperature, salt concentration, pH) and are characterised based on temperature needs → many archea

Question 7

effect of temperature on growth rate

Answer 7

membrane gelling at minimum temperature; gradual slope when moving towards optimum temperature (enzymatic reactions increase); steep drop after optimum temperature + thermal lysis at higher than optimum

Question 8

membrane gelling

Answer 8

membrane becomes solid → transport procession so slow that growth cannot occur

Question 9

thermal lysis

Answer 9

collapse of the cytoplasmic membrane

Question 10

pH extremophiles

Answer 10

though they live at very high or low pH, the cell’s internal pH remains near neutrality → due to secreted enzymes

Question 11

halophiles

Answer 11

salt-loving organisms → need moderate to large quantities of NaCl

Question 12

microbiome definition

Answer 12

all of the microorganisms within a specific environment

Question 13

sporulation

Answer 13

bacterial endospores → strategy for the survival of unfavourable conditions