Microorganisms

Question 1

What are the two main types of cells?

Answer 1

Prokaryotes and Eukaryotes

Question 2

What is the largest group of bacteria?

Answer 2

Proteobacteria

Question 3

What type of stain is the Gram stain?

Answer 3

Differential stain

Question 4

What color do Gram-positive bacteria appear after staining?

Answer 4

Purple

Question 5

What color do Gram-negative bacteria appear after staining?

Answer 5

Red

Question 6

What are the two major groups of bacteria based on Gram staining?

Answer 6

Gram-positive and Gram-negative

Question 7

How many genera and species of Proteobacteria have been identified?

Answer 7

More than 460 genera and 1600 species

Question 8

What are some genera of Gram-positive bacteria?

Answer 8

• Bacillus
• Clostridium
• Lactobacillus
• Streptococcus
• Mycoplasma

Question 9

What is a key function of fungi?

Answer 9

Production of antibiotics

Question 10

What type of fungi are responsible for the decomposition of complex organic matter?

Answer 10

Saprotrophic fungi

Question 11

What type of fungi cause diseases in plants and animals?

Answer 11

Parasitic fungi

Question 12

How many fungi are known to infect humans?

Answer 12

About 200 fungi

Question 13

What is the general innate immunity of humans towards fungi?

Answer 13

High degree of innate immunity

Question 14

What is the significance of the genus Streptomyces?

Answer 14

Best known and most studied member of Gram-positive bacteria

Question 15

What is Amanita caesarea commonly known as?

Answer 15

Caesar’s mushroom

Question 16

What does the term ‘mycorrhiza’ refer to?

Answer 16

Symbiotic association between fungi and plant roots

Question 17

What is the primary structure that increases nutrient uptake in ectotrophic mycorrhiza?

Answer 17

Fungal sheath

Question 18

What are the characteristics of fungi?

Answer 18

• Heterotrophic for carbon
• Eukaryotic cell structure
• Filamentous in most groups
• Cell wall present
• Spores produced in reproduction
• Non-motile except in reproduction in some fungi

Question 19

What is a hypha?

Answer 19

A filament of fungi

Question 20

What is the network of branched hyphae called?

Answer 20

Mycelium

Question 21

What are ‘fairy rings’?

Answer 21

Patterns formed by the growth of fungi

Question 22

What are the two major types of fungal spores?

Answer 22

• Sexual spores
• Asexual spores

Question 23

What is the significance of asexual spores?

Answer 23

Produced in large numbers for dispersal

Question 24

What type of fungi are Chrytridiomycetes?

Answer 24

Lower fungi

Question 25

What are zygospores?

Answer 25

Sexual spores produced by Zygomycetes

Question 26

What is the generation time (g) for Escherichia coli?

Answer 26

17 minutes

Question 27

What environmental factors affect microbial growth?

Answer 27

* Nutrient availability * Temperature * pH * Aeration * Moisture content * Presence of inhibitory substances

Question 28

What are the three phases of a typical bacterial growth curve?

Answer 28

* Lag phase * Exponential phase * Stationary phase

Question 29

What is the survival structure formed by Bacillus and Clostridium?

Answer 29

Endospores

Question 30

What are the characteristics of endospores?

Answer 30

* Most resistant forms of life * Can withstand extreme conditions * Remain viable in a metabolically inactive state for years

Question 31

What is Gruinard Island known for?

Answer 31

Testing anthrax as a biological weapon

Question 32

What was the outcome of the Amerithrax investigation?

Answer 32

Investigation into anthrax letter attacks post-9/11

Question 33

What is the importance of identifying Bacillus anthracis strains in investigations?

Answer 33

Essential for identifying and eliminating criminal suspects

Question 34

What is the significance of identifying the exact strain of Bacillus anthracis?

Answer 34

It is essential in the investigation of rax letter attacks. ## Footnote This demonstrates the importance of accurate microbial identification in forensic science.

Question 35

How has forensic science evolved in relation to DNA evidence?

Answer 35

It has increasingly depended on DNA evidence for the identification and elimination of criminal suspects. ## Footnote This trend has influenced microbial forensics as well.

Question 36

What role does DNA fingerprinting play in microbial forensics?

Answer 36

It is fundamental to the identification of specific micro-organisms used in biocrimes. ## Footnote Microbial forensics has adapted DNA techniques from general forensic science.

Question 37

What are bacterial endospores?

Answer 37

They are structures that differ physically and chemically from vegetative cells. ## Footnote Endospores have a much lower water content and contain calcium dipicolinate.

Question 38

How do endospores differ from vegetative cells in terms of water content?

Answer 38

Endospores have 15% water compared to 70% water in vegetative cells. ## Footnote This difference contributes to their resilience.

Question 39

What compound is found in large amounts in bacterial endospores?

Answer 39

Calcium dipicolinate. ## Footnote This compound is less abundant in vegetative cells.

Question 40

What are bacterial cysts?

Answer 40

Modified vegetative cells that develop a thick, resistant cell wall. ## Footnote An example is the rod-shaped vegetative cell in Azotobacter.

Question 41

What are the characteristics of Azotobacter cysts?

Answer 41

They are resistant to desiccation, mechanical disintegration, and UV & ionising radiation. ## Footnote However, they are not especially heat resistant.

Question 42

True or False: Bacterial cysts are especially heat resistant.

Answer 42

False. ## Footnote Unlike endospores, cysts do not exhibit significant heat resistance.

Question 43

Fill in the blank: Endospores contain a much lower water content, approximately _______.

Answer 43

15%.

Question 44

Fill in the blank: Vegetative cells contain small quantities of calcium dipicolinate as an intermediate in the synthesis of _______.

Answer 44

lysine.