Principles Of Microbiology Flashcards
What are the four classes of cellular molecules?
Proteins, nucleic acids, lipids and polysaccharides.
Six characteristics of living organisms.
Compartmentalization and metabolism, growth and reproduction, differentiation, communication, movement and evolution.
Compare machine and coding functions of microbial cells.
Machines: metabolism and enzymes accelerating it.
Coding devices: store and process DNA.
They dependent on each other and have to be highly coordinated in order to provide growth and reproduction.
What a microbial habitat?
It’s the environment in which the cell population lives.
What differs microbial community from microbial population?
Population: a group of cells originated from the same cell.
Community: populations interacting.
How can microrganisms change the characteristics of their habitats?
They remove and excrete nutrients to their habitats. They are therefore open systems.
Were the earliest life forms cellular?
No, there were small molecules of RNA able to replicate themselves.
Why is it that cellular life is the only form of life we see on Earth today?
They hold the fundamental characteristics of life so they were selected.
How old is Earth and when did cellular life forms first appear?
It’s 4.6 billion years old and the first cellular life (methanogens & other anaerobic organisms) is 3.8 billions years old.
How can we use science to reconstruct the sequence of organisms that appeared of Earth?
Using biomarkers that can be identified in ancient rocks.
Where are most microbial cells located on Earth?
Undergroung in oceans and terrestrial subsurfaces.
In what ways are microorganisms important in the food and agricultural industries?
Fermentation, food preservation, Nitrogen metabolism (nodules in legumes’ roots) and rumen.
List two fuels that are made by microorganisms.
Methane and ethanol.
What is biotechnology?
It’s the genetic modification of microorganisms in order to enable them to produce commercial items such as insulin and other hormones.
What major discovery emerged from Cohn’s study of hear resistance in microorganisms?
Bacteria that form endospores.
Define term sterile.
Sterile is a medium where there are no microorganisms.
How did Pasteur’s swan-neck flask experiment show that the concept of spontaneous generation was invalid?
The fresh air without the microorganisms was unable to create life, which appeared only when the sterile liquid was in touch with microorganisms.
How do Koch’s postulates prove cause and effect for the culture of microorganisms?
By inoculating microorganisms present in sick animals into health animals.
What advantages do solid media offer for the culture of microorganisms?
They enable colonies to grow and make easy to identify then.
What is a pure culture?
It is a culture originated from one single cell.
What is the enrichment culture technique?
It’s a selection of microorganisms by manipulating nutrient and incubation conditions.
What’s chemolithotrophy?
It’s the oxidation of inorganic compounds such as ammonia and CO2 linked to energy conservation. Therefore some microorganisms can produce ATP from them.
How might you distinguish a phototrophic microorganism from a chemotrophic one by simply looking at it under a microscope?
The photrothopic ones are colourful because of their pigments.
What are extremophiles?
Microorganisms that require extreme conditions to survive such as high temperatures and salty environments.
