Lecture 1. Introduction To Microbiology

Question 1

What is microbiology?

Answer 1

Study of organisms too small to see with the naked
eye (bacteria, archaea, fungi, protozoa)
But some can be much larger, define microbiology NOT purely by size

Question 2

What was Whittaker’s “Five kingdoms’

Answer 2

The crown taxa (plantae, Fungi, animalia), protista and bacteria
Incorrect

Question 3

What are the actual three domains?

Answer 3

Bacteria, archaea and eukarya

Question 4

What is the average size of most bacteria?

Answer 4

1-6 μm

Question 5

What were archaea once thought to be?

Answer 5

Extremophiles only

Question 6

When was the first non-extreme archaeon isolated?

Answer 6

2004

Question 7

Are there any known pathogenic archaea?

Answer 7

No

Question 8

What is the size of the largest fungal colony?

Answer 8

~10,000kg

Question 9

What are most eukaryotes?

Answer 9

Protists

Question 10

What is the size range of protists?

Answer 10

1-150μm

Question 11

What is the distribution of microorganisms in cloud water?

Answer 11

10³-10⁴/ml

Question 12

What is the distribution of microorganisms in sea water?

Answer 12

10⁶/ml

Question 13

What is the distribution of microorganisms in soil?

Answer 13

10⁷-10⁹/g

Question 14

What is the distribution of microorganisms in rivers and lakes?

Answer 14

10⁵-10⁷/ml

Question 15

What is the distribution of microorganisms in the marine subsurface?

Answer 15

10⁶-10¹¹/ml

Question 16

What is the distribution of microorganisms in human cells?

Answer 16

10¹³-10¹⁴

Question 17

What is the distribution of microorganisms in bacterial cells?

Answer 17

10¹⁴

Question 18

What is the estimated total of microbial cells on earth?

Answer 18

4-6x10³⁰

Question 19

Why are bacteria and archaea important?

Answer 19

Major portion of biomass on Earth and key reservoirs of nutrients for all life

Question 20

Why are there so many microorganisms?

Answer 20

Rapid growth rate even in the environment
Many chances of speciation through random mutations
Exchange of genetic material (lateral gene transfer)
Every available niche is occupied by specifically adapted
microbes
A very long evolutionary history (~3.8 billion years)

Question 21

What does phototroph mean?

Answer 21

Energy from light

Question 22

What does chemotroph mean?

Answer 22

Energy from chemical bonds

Question 23

What does organotroph mean?

Answer 23

Organic compounds as e⁻ donors

Question 24

What does lithotroph mean?

Answer 24

Inorganic compounds as e⁻ donors

Question 25

What does autotroph mean?

Answer 25

CO₂ as carbon source

Question 26

What does heterotroph mean?

Answer 26

Organic carbon as carbon source

Question 27

What are plants and cyanobacteria?

Answer 27

Photolithoautotrophs (Use light energy, water as e⁻ donor, fix carbon dioxide)

Question 28

What are animals and E. coli?

Answer 28

Chemoorganoheterotroph (Use chemical bond energy (e.g. O₂), organic compounds (e.g. sugars) as e⁻ donor and carbon source)

Question 29

What is Thiobacillus spp.?

Answer 29

Chemolithoautotroph (Use chemical bond energy, inorganic compound (reduced sulfur compounds) as e⁻ donor, fix carbon dioxide)

Question 30

What are the primary nutrients required to grow bacteria?

Answer 30

Macronutrients and micronutrients

Question 31

What are examples of macronutrients?

Answer 31

C (CO₂ or organic C), H, O, N, S, P, K, Mg, Na, Ca, Fe

Question 32

What are examples of micronutrients?

Answer 32

B, Cr, Co, Cu, Fe, Mn, Mo, Ni, Se, W, V, Zn

Question 33

What do prototrophs synthesise?

Answer 33

All their own cellular components (including all amino acids, nucleotides, vitamins)

Question 34

Why are there no complex materials in the defined medium for E. coli?

Answer 34

E. coli can make them all itself

Question 35

How does bacteria grow?

Answer 35

Asexual reproduction by binary fission or budding Exponential growth because one cell becomes two becomes four etc. Incomplete separation produces pairs or larger assemblies of bacteria

Question 36

What are the four stages of microbe growth?

Answer 36

Lag phase Log/exponential phase Stationary phase Death phase

Question 37

What occurs in the lag phase?

Answer 37

Microbes adapting to (new) conditions

Question 38

What occurs in the log/exponential phase?

Answer 38

Exponential growth in microbes

Question 39

What occurs in the stationary phase?

Answer 39

Limitation by nutrients, buildup of waste products that inhibit growth

Question 40

What occurs in the death phase?

Answer 40

Organisms start dying off and may lyse

Question 41

What is selective media?

Answer 41

Media that allows the growth of only some types of media (used to culture/identify presumed pathogens from clinical specimens)

Question 42

What is differential media?

Answer 42

Media that allows the identification of organisms based on growth and appearance on that medium (often based on colour differences)

Question 43

What is ApiZym?

Answer 43

A common test system, mainly optimised towards pathogens