Bacteria history and basics

Question 1

What did Antoine van Leewenhoek do?

Answer 1

Fashioned the first microscope to observe cells

Called them animalcules

Question 2

What did Louis Pasteur do?

Answer 2

Created the ‘germ theory’ of infection
Observed that bacteria were responsible for food spoilage and could be killed with heat
Early experiments on vaccinations using cultured bacteria

Question 3

What did Joesph Lister do?

Answer 3

Developed carbolic acid as a disenfectant

Question 4

What did Ignaz Semmelweis do?

Answer 4

Hand-washing to prevent the spread of infections

Question 5

What did Robert Koch do?

Answer 5

Developed the petri dish containing agar gel to culture bacteria

Question 6

What are the 4 Kock postulates?

Answer 6

Bacteria can be isolated from a diseased organism
Bacteria can be cultured in a lab
Bacteria should cause the same disease in a different host
The same bacteria can be re-isolated from the second host

Question 7

What did Hand Christian Gram do?

Answer 7

Made the Gram stain

Question 8

What does the Gram stain do?

Answer 8

Crystal violet stains Gram-positive bacteria purple and safranin stains Gram-negative bacteria red

Question 9

What do Gram-positive bacteria have?

Answer 9

Lots of peptidoglycan for the crystal violet stain to grab on to

Question 10

What do Gram-negative bacteria have?

Answer 10

Less peptidoglycan that is beneath an outer membrane which has lipopolysaccharides on the outside

Question 11

Describe the prokaryotic dogma

Answer 11

No nuclear membrane- ‘nucleoid’
Naked DNA- no true histones
Chromosomes are exposed to the cytoplasm
Transcription and translation are coupled
No introns or RNA capping
Clustering of related genes into co-regulated operons
Rapid exchange and evolution of genetic material

Question 12

Describe obligate aerobes

Answer 12

Can only grow in the presence of molecular oxygen

Aerobic respiration produces ATP

Question 13

Describe obligate anaerobes

Answer 13

Killed by the presence of molecular oxygen
Anaerobic or fermentation produces ATP
Oxygen will generate reactive oxygen species which will damage the proteins and DNA if not detoxified

Question 14

Describe facultative aerobes/anaerobes

Answer 14

Prefer to grow in the presence of molecular oxygen

Can switch metabolism

Question 15

Describe autotrophs

Answer 15

‘Fix’ carbon dioxide to use as their sole carbon source

Question 16

Describe lithotrophs

Answer 16

‘Rock devouring’

Use inorganic compounds as e- donors/energy source

Question 17

Describe chemolithoautotrophs

Answer 17

Can do everything

Question 18

Describe photoautotrophs

Answer 18

Use photosynthesis

Can ‘fix’ carbon dioxide

Question 19

Describe photoheterotrophs

Answer 19

Use photosynthesis

Can’t ‘fix’ carbon dioxide

Question 20

Describe mixotrophs

Answer 20

Any microbe that can adapt its metabolism to different conditions

Question 21

Describe thermophiles

Answer 21

Like hot conditions

Question 22

Describe psychrophiles

Answer 22

Like cold conditions

Question 23

Describe halophiles

Answer 23

Like salty conditions

Question 24

Describe piezophiles

Answer 24

Like high-pressure conditions

Question 25

Describe acidophiles

Answer 25

Like low pH conditions

Question 26

Describe Helicobacter pylori

Answer 26

Gram-negative curved rod 
~1μm 
Microaerophillic metabolism 
Obligate human gut commensal 
Dynamic genome 
Potentially every human carrier has a different strain 
Causes stomach ulcers and cancers