Introduction to Microbiology in Agriculture

Question 1

Roles of Micro-organisms

Answer 1

They cycle soil nutrients, aid in digestion, and play roles in food processing.

Question 2

How were Eukaryotic cells formed

Answer 2

Formed from symbiotic associations among archaea, proteobacteria (mitochondria), and cyanobacteria (chloroplasts).

Question 3

Examples of Microbial roles in normal health and function

Answer 3

Rhizobia bacteria fix nitrogen for legumes, aiding plant growth.
Ruminants rely on gut microbes to digest cellulose in their diet.

Question 4

What effects can Micro-organisms have on food

Answer 4

Food spoilage
molds such as in blue cheese

Question 5

What are the four types of micro-organisms

Answer 5

photoautotrophs, chemoautotrophs, photoheterotrophs, and chemoheterotrophs.

Question 6

What type of Microorganism are pathogenic bacteria

Answer 6

Chemoheterotrophs

Question 7

Main differences between Eukaryotes and prokaryotes

Answer 7

prokaryotes are smaller, can be anaerobic, and lack membrane-bound organelles

Question 8

Differences between bacteria and viruses

Answer 8

Structures: Viruses are particles (virions); bacteria are single cells.
Genomes: Viruses contain DNA or RNA; bacteria have DNA.
Replication: Viruses replicate within living cells; bacteria mostly by binary fission.

Question 9

What is involved in the diagnosis of a bacterial disease

Answer 9

detecting the organism, its products, or immune responses.

Question 10

What are 3 methods of diagnosing bacterial disease

Answer 10

Microscopy, culture, and molecular methods like PCR are common.

Question 11

What are bacteria?

Answer 11

Bacteria are microscopic, single-cell, self-replicating organisms that exist in a wide variety of shapes and sizes

Question 12

Why is it important to classify and name bacteria?

Answer 12

To group similar organisms together and ensure consistent identification and discussion of specific bacteria.

Question 13

How were bacteria historically classified?

Answer 13

According to their phenotype, including observable traits such as size, shape, arrangement, and structures like endospores, capsules, and flagella.

Question 14

What modern method is used to classify bacteria?

Answer 14

By their genotype or genetic makeup, particularly through sequencing 16S rRNA genes and whole genome sequencing.

Question 15

What are 16S rRNA genes used for in bacterial classification?

Answer 15

To track evolutionary changes and construct phylogenetic trees due to their essential role in mRNA translation and high conservation.

Question 16

What is the binomial naming system for bacteria?

Answer 16

A system where the first name is the genus (capitalized) and the second name is the species (lowercase), both italicized in print or underlined when handwritten.

Question 17

What is an example of bacterial nomenclature and its abbreviation?

Answer 17

Escherichia coli, often abbreviated as E. coli.

Question 18

What defines a bacterial species?

Answer 18

A group of organisms that are very similar genetically and phenotypically.

Question 19

What major reclassification occurred in 2016 due to 16SrRNA gene analysis?

Answer 19

Clostridium difficile was reclassified to Clostridioides.

Question 20

What is the ‘International Code of Nomenclature of Prokaryotes’?

Answer 20

A set of rules for naming bacterial species, published by the ‘International Journal of Systematic and Evolutionary Microbiology’.

Question 21

How can bacterial phenotypes be observed?

Answer 21

Through their growth in the presence of oxygen, on selective or differential media, and by staining and microscopy.

Question 22

What is the Gram reaction?

Answer 22

A staining method that differentiates bacteria by their cell wall composition, staining them either purple (gram-positive) or pink/red (gram-negative).

Question 23

What structures can be observed using special stains in bacteria?

Answer 23

Endospores, capsules, and flagella.

Question 24

How is motility observed in bacteria?

Answer 24

Microscopically using a hanging drop preparation and macroscopically by using semisolid motility media.

Question 25

What biochemical tests can identify bacterial metabolic traits?

Answer 25

Tests for enzymes such as catalase, oxidase, coagulase, and urease.

Question 26

What are taxonomic keys used for in bacteriology?

Answer 26

To identify bacteria at the genus or species level based on their positive or negative results to various traits and tests.

Question 27

How is DNA used for bacterial identification and classification?

Answer 27

Through techniques like PCR and genomic sequencing, including 16SrRNA gene sequencing and multi-locus sequence typing (MLST).

Question 28

Why is it important to identify different bacterial strains?

Answer 28

Because different strains within the same species can have varying abilities to cause disease.

Question 29

Give an example of a bacterial species with different strains having different pathogenic abilities.

Answer 29

Escherichia coli, which includes a harmless commensal strain, a probiotic strain, and pathogenic strains causing diseases.

Question 30

Why is it important to identify bacterial species and strains correctly?

Answer 30

To ensure the correct bacteria are used for specific applications and to apply the appropriate treatment to reduce disease burden.