Microbiology - ICT2 (Lectures 1 - 8) Flashcards
How was ‘spontaneous regeneration’ disproved?
Pasteur
It was a theory that life spontaneously evolved. Was able to disprove by using a bacterial broth, that underwent heat sterilisation. After being treated with heat the liquid was safe to keep
What size of microorganism can be seen under a microscope?
If they are bigger than 0.3um they can be seen under the microscope
What microscope is used to view bacteria and protozoa?
Light microscope, if greater than 0.3um
What is the size of viruses?
0.01 - 0.3 um
How are viruses visualised?
Electron microscopy
Differences between Pro and Eukaryotes
Eukaryotes have membrane bound cells
Eukaryotes have a simple cell wall, whereas Porkaryotes have a complex cell wall
Types of prokaryotes are?
Bacteria
Archaea
Where is bacteria found?
- Soil
- Water
- Animals
- Other environments
What kind of environment s is Archaea found in?
Can survive in extreme environments
Examples of Archaea environments?
- Hot springs
- Freezing water
- Highly Acidic
- Alkaline environments
Examples of Eukaryote organisms?
- Algae
- Fungi
- Protozoa
What happened as Eukaryotes evolved?
Eukaryotes evolved and gained
- Mitochondria
- Chloroplasts
- Internal membranes
What cells do eukaryotes form?
Cells of microorganisms in animals and plants
What was the origin of Mitochondria?
Mitochondria was a type of bacteria.
Most likely endosymbionts
- evolved to grow in side of the eukaryote
- this is for evolutionary advantage
What is the endosymbiotic hypothesis?
This is the process when a certain bacteria are brought inside a eukaryote cell to co evolve.
This causes an evolutionary advantage
What would have been the origin of chloroplasts ?
Chloroplast would have been a cyanobacteria
What are the features of PROKARYOTES?
- DNA not enclosed in membrane, it is circular and super coiled
- DNA is not associated with histones + there is a low protein content
- No organelles
- Divide by binary fission
- Form biofilms
- Complex cell wall
- 70s ribosomes
What is the DNA in PROKARYOTES?
DNA in prokaryotes is not enclosed in a membrane
The DNA is circular and super coiled
DNA in prokaryotes is not associated with histones
There is a low protein content
What organelles are present in PROKARYOTES?
No organelles
How do PROKARYOTES replicate?
Prokaryotes divide by binary fission
What ribosomes are present in PROKARYOTES?
70 s
What are the features of EUKARYOTES?
- Discrete nucleus with nuclear membrane
- Linear genetic material
- DNA has a high histone content and non - histone proteins
- Organelles
- Divide by mitosis and meiosis
- Simple cell wall if present
- 80s ribosomes
What is the structure of EUKARYOTE DNA?
Eukaryotes have linear genetic material
The DNA has a high histone content and non-histone proteins
Are Organelles present in EUKARYOTES?
Organelles are present in eukaryotes
What ribosomes are present in a EUKARYOTE?
80 s ribosomes
How do EUKARYOTES reproduce?
Divide by mitosis and meiosis
What type of cell wall does a PROKARYOTE have?
A complex cell wall
What type of cell wall does a EUKARYOTE have?
A simple cell wall
How have mitochondria developed?
There would have been aerobic bacteria in the cytoplasm of primitive eukaryotes.
The bacteria would have provided energy in return for safety
They have co evolved with the eukaryotic organism
Most likely due to the endosymibiotic hypothesis
What process lead to photosynthesis?
Phototropic bacteria (Bacterial cells that can do photosynthesis) would have been incorporated in the the cells This would allow photosynthesis to occur
Where does microbial diversity occur in PROKARYOTES and EUKARYOTES?
- Structure
- Function
- Behaviour
- Adaption
How do you calculate Phlyogenetic Relationships?
Using the gene sequencing of 16s (pro) and 18s (eu) ribosomal RNA
Looking at the sequences of DNA and RNA
You see how they are related by how close the sequences are
- The gene of the ribosomal RNA is amplified
- A computer compares the sequences and counts every position where there is a difference
You get ED, the evolutionary distance
What does RNA do?
Does the translation, to make protein from RNA proteins and RNA with catalytic activity
What factors of replication allow variations to be compared ?
If the 16s and 18s rRNA need to perform a function,
- There is a lot of selective pressure to not mutate these sequences
- Change is not very rapid
This allows you to see when an organism diverged from each other based on how related the 16s and the 18s are from each other
How is the ED (Evolutionary distance) shown?
Construction of tree where length of line is proportional to ED
- how close the lines are to each other tells you how related those organisms are
Why are viruses not on the Phylogenetic tree?
Viruses do not contain ribosomes and therefore cannot be analysed in the same way
What are the features of Virus genome?
Have very small genomes
e,g SARS -CoV-2
is only 20 kilo bases
When did viruses evolve?
If they can infect bacteria, then probably appeared as bacteria was evolving
If bacteria is able to infect humans then they could not have evolved before them
How is Taxonomiy and Classification based?
originally based on phenotypic and metabolic behaviour
G-C content has also been used
Now clarified by genotyping
How are microorganisms named?
Named using the binomial nomenculture
after Linnaeus
How do you use systematic nomenclatures for microorganisms?
- Genus come first with a capital letter
- Species follows with no capital
Name is always written in italics or underlined
How do microbial populations interact?
- Can form Ecosystems
- Associate with other populations in microbial communities - Competition for nutrients and niches
- Interact with each other in beneficial or harmful ways - Antagonism
- production of toxins and antibodies - Cooperation
- one group of microorganisms provide nutrients fro others
- e.g oral & gut flora
What is the environment for related cells called?
Groups of related cells live in a habitat or niche
What is the quantity of the types of cells in humans?
Human cells?
Microorganisms?
Human cells - 10^13
Microorganisms - 10^16
Where do microorganisms live?
What do microorganisms form?
- Water
- Soil
- Plants
- Animals
Microorganisms form the micro flora of their environment
What relationships can a microorganism have with the host (if at all)?
- Mutualistic
- Saprophytic
- Parasitic
What is a Mutualistic relationship?
Grow together
- A good gut microbe
What is a Saprophytic relationship?
One which just digests
- Fungi growing on mushroom
What is a Parasitic relationship?
Still actively trying to kill
- Parasitic worm taking nutrients from body
What are beneficial uses of microorganisms?
- In Agriculture
- Digestive process in ruminants
- Saprophytic bacteria
- Silage making
- Food industry
How are microorganisms beneficial in agriculture?
Legumes and nodules on root
- Bacteria living in the nodules fix nitrogen, forming part of the nitrogen cycle
- reduces the need for fertilisers
- Have a symbiotic relationship
How are microorganisms beneficial in the digestive process of ruminants?
Sheep and Cattle
The bacteria ruminococci is present
- This digests cellulose
Symbiosis
How are microorganisms beneficial as saprophytic bacteria?
Present in the soil
- convert in to forms that are accessible to plants
They take part in the carbon, nitrogen and sulphur cycles
Are there any problems with saprophytic bacteria?
A source of animal and plant disease
- if they get in to the human body
How are microorganisms beneficial for Silage making?
Hay stored anaerobically is fermented by
- lactobacillus sp.
They metabolise plant sugars
How are microorganisms beneficial in the Food Industry?
In Dairy Products
- Lactose in milk
- Metabolised by bacteria to lactic acid
In Butter
- lactic acid starter culture added to cream
- E.g Lactococcus cremoris
In Cheese
- Coagulation and fermentation of milk
- Addition of other bacteria, to make certain cheese
In Yoghurt
Low fat milk, pasteurised & inoculated with
- Lactobacillus bulgarius
- Streptococcus bulgarius
What is Monosodium glutamate?
Is produced from L-glutamic acid from Corynebacteria glutamicum
It is grown aerobically on molasses
This tends to be a flavouring that has additive properties and stimulates the brain in different ways
How does Vinegar use microorganisms beneficially?
Ethyl alcohol to acetic acid by genera
- Acetobacter or Gluconobacter
How does Citric acid used microorganisms beneficially?
Fermentation using Aspergillus niger
What are forms of edible fungi
- Alcoholic drinks
- Baked goods
- Yeast
How are antibiotic produced?
Produced by large scale
