Introduction to Microbiology

Question 1

What is microbiology?

Answer 1

The study of life and microorganisms that are too small to be seen with the naked eye

Question 2

What is a prokaryote and which microbe groups are prokaryotes?

Answer 2

Prokaryotes lack a nucleus and any other membrane bound organelles. They include bacteria and archaea

Question 3

What is a eukaryote and which microbe groups are eukaryotic?

Answer 3

Eukaryotic cells contain complex structures enclosed within membranes as well as a nucleus. Fungi, protozoa and algae.

Question 4

What are non-living entities?

Answer 4

These are viruses. They are called non-living because they only reproduce in other organisms. They are microorganisms.

Question 5

Why would life not exist without microorganisms?

Answer 5

Earth - 4.6 billion years old. 1st life was bacterial - 3.8 billion years ago. Anoxic atmosphere - anaerobic metabolism such as methanogens producing methane. Evolved to light harvesting organisms - purple bacteria. Evolved to cyanobacteria - oxygenated atmosphere. Eukaryotic cells evolved. Life exclusively microbial until 500-800 million years ago

Question 6

Why can microbes be harmful?

Answer 6

Microorganisms can cause disease such as malaria (but few microbes are pathogenic) They can cause veterinary and agricultural problems They can cause food spoilage or contaminate water supplies

Question 7

Why are microbes essential for life?

Answer 7

Release oxygen into the atmosphere Soil, marine and freshwater microbes form basis of foodchains In agriculture they recycle nutrients, carbon, sulphur and phosphorus Microbes in the gut of ruminant animals breakdown cellulose Fermented foods such as alcohol,vinegar, cheese Food additives such as citric acid Soil microbes break down organic matter Degrade or detoxify pollutants such as oil and mercury

Question 8

How can microbes be used as biological insecticides?

Answer 8

Microbes that are pathogenic to insects can be used on agricultural crops. Bacillus thuringiensis infections are fatal in insects but harmless to humans and plants.

Question 9

What industrial chemicals can be made by the help of microbes?

Answer 9

Vitamins, alcohols and solvents, organic acids, enzymes and drugs. Can also be manipulated to make substances not normally made by the microbe - e.g. digestive aids, insulin

Question 10

Microorganisms are ubiquitous. What does this mean?

Answer 10

This means they are present everywhere. In all types of ecological niches.

Question 11

List some examples of ecological niches where microbes may be found.

Answer 11

Soils, oceans, freshwater, Antarctica, hot springs, hydrothermal vent, nuclear reactors

Question 12

What is an ecological niche?

Answer 12

An ecological niche is the role and position a species has in its environment; how it meets its needs for food and shelter, how it survives, and how it reproduces.

Question 13

Microorganisms exist in interacting populations called…

Answer 13

Microbial communities

Question 14

The environment in which a microbial population lives in is its…

Answer 14

Habitat

Question 15

The microbial communities and physical and chemical constituents in their environment is referred to as an…

Answer 15

Ecosystem

Question 16

What is the study of microbes in their natural environments called?

Answer 16

Microbial ecology

Question 17

What is the diversity and abundance of microbes in a microbial community controlled by?

Answer 17

Resources such as food and conditions such as temperature, pH,

Question 18

Microbes can interact with each other to…

Answer 18

Help microbes that can help each other and kill off any competition

Question 19

Microbes interact with their chemical and physical environments in what ways?

Answer 19

Resources are utilised. Waste products are released and environmental conditions may be altered.

Question 20

Microbial communities are dynamic, what does this mean?

Answer 20

They are constantly prone to change - they expand and contract

Question 21

Describe one way in which a microbial community is dynamic

Answer 21

O2 is essential to some microbes but poison to others. O2 consuming microbes remove oxygen from a habitat. The habitat becomes anoxic. Conditions favour the growth of the anaerobic microbe.

Question 22

Microbes can attach to solid surfaces and form…

Answer 22

Biofilms

Question 23

How can biofilms be good?

Answer 23

They can protect mucous membranes from harmful microbes

Question 24

How can biofilms be negative?

Answer 24

They can clot medical implants, joint prostheses and catheters. They can cause infections, e.g. endocarditis which is the inflammation of the heart

Question 25

Why are biofilms such a problem?

Answer 25

They are often antibiotic resistant

Question 26

What are microbial communities present in or on the human body called?

Answer 26

The normal microbiota / microflora

Question 27

Why is the normal microbiota a good thing?

Answer 27

They prevent the growth of pathogens and produce growth factors such as folic acid and vitamin K.