Microbiology

Question 1

State what is meant by a gram negative bacillus bacterium (2)

Answer 1

• gram - have capsule / lipopolysaccharide
• bacillus rod shaped

Question 2

Suggesst why the microbiologist diluted the original sample by 10-2 but could not calculate the number of legionella per cm3 (1)

Answer 2

• there were too many colonies to count/ colonies clumped

Question 3

Describe two major feature of a eukaryote which would allow you to distinguish it from a prokaryote (1)

Answer 3

• have nucleus
• membrane bound organelles
• 80s ribosomes
• DNA is linear

Question 4

suggest when she dilutd the original sample by 10-5 a lower number of legionella bacteria per cm3 was calculated (1)

Answer 4

the extra dilution give additional error/may not have mixed fully/inaccurate repreentation of whole sample/not valid to count less than 30 colonies/ too few to be statisticlly significant