Chapter 1 Flashcards
two themes of microbiology
- understanding basic life processes
2. applying that knowledge to the benefit of humans
microbes play important roles in…
- medicine
- agriculture
- industry
importance of microorganisms (5)
- oldest form of life
- largest mass of living material on Earth
- carry out processes for biogeochemical cycles
- can live in places unsuitable to other organisms
- other life forms require microbes to survive
cell
dynamic entity forms fundamental unit of life
cytoplasmic membrane
barrier that separates inside of cell to outside environment
cell wall
present in most microbes, confers structural strength
six characteristics of living systems
- metabolism
- reproduction
- differentiation
- communication
- movement
- evolution
metabolism
chemical transformation of nutrients
reproduction
generation of two cells from one
differentiation
synthesis of new substances or structures that modify the cell (in some microbes, not all)
communication
generation of, and response to, chemical signals (in some microbes, not all)
movement
via self-propulsion, many forms in microbes
evolution
genetic changes in cells that are transferred to offspring
cells function as ________ and ________
catalysts, coding devices
cells as catalysts function to…
carry out chemical rxns
cells as coding devices
store and process info that is eventually passed on to offspring during reproduction through DNA and evolution
enzyme
protein catalyst of cell that accelerates chemical rxns
transcription
DNA produces RNA
translation
RNA makes protein
________ is the link between cells as machines and cells as coding devices
growth
microbial communities
populations of interacting microbes existing in nature
habitat
the environment in which a microbial population lives
ecosystem
all living organisms plus physical and chemical constituents of their environment
microbial ecology
the study of microbes in their natural environment
diversity and abundances of microbes are controlled by ________ and ________
resources (nutrients) and environmental conditions (temperature, pH, O2 etc.)
ecosystems greatly influenced (if not controlled) by…
microbial activity
microorganisms change the ________ and ________ properties of their habitats through their activities (excreting waste, removal of nutrients from environment)
physical, chemical
the first replicating entities may not….
have been cells
last universal common ancestor (LUCA)
common ancestral cells from which all cells descended
the Earth is ________ years old
4.6 billion
the first cells appeared ________ years ago
3.8-3.9 billion
the atmosphere was anoxic until ________ years ago
2 billion
metabolisms were exclusively ________ until evolution of ________
anaerobic, oxygen-producing phototrophs
life was exclusively microbial until ________ years ago
1 billion
global estimate of microbial cells
5 X 10^30
most microbial cells found in ________ and ________ subsurfaces
oceanic, terrestrial
microbes can be both ________ and ________ to humans
beneficial, harmful
Harmful microorganisms are ________ and ________
infectious disease agents, pathogens
more microorganisms are ________ than ________
beneficial, harmful
positive impacts of microbes on agriculture
- nitrogen-fixing bacteria
- cellulose-degrading microbes in rumen
- regeneration of nutrients in soil and water
negative impacts of microbes on agriculture
- diseases in plants and animals
positive impacts of microbes in food
- microbial transformations (i.e. fermentations) yield (dairy products such as yogurt and cheese; other products such as pickles, leavened breads and beer)
negative impacts of microbes in food
- food spoilage by microorganisms requires specialized preservation of many foods
microbes in biofuel production
methane, ethanol and hydrogen
bioremediation
microbes cleaning up pollutants
microbes can be exploited for production of…
antibiotics, enzymes and other various chemicals
biotechnology
genetic engineering of microbes to generate products of value to humans (i.e. insulin)
microbiology as a career
- clinical medicine
- research and development - pharmaceutical, biochemical/chemical, biotechnology
- microbial monitoring - food and beverage industries, public health and government
microbiology began with the ________
microscope
Antoni van Leeuwenhoek (1632-1723)
first to describe bacteria, any further progress would require the development of more powerful microscopes
Louis Pasteur (1822-1895)
discovered. ..
1. living organisms discriminate between optical isomers
2. alcoholic fermentation was a biologically mediated process
3. spontaneous generation was not true, disproved theory
4. and developed vaccines for anthrax, fowl cholera and rabies
Robert Koch (1843-1910)
- demonstrated link between microbes and infectious diseases (identified causable agents of anthrax and TB)
- koch’s postulates
- developed techniques for obtaining pure cultures of microbes
- awarded nobel prize in 1905
koch’s first postulate
suspected pathogen must be present in all cases of the disease and absent from healthy animals
koch’s second postulate
suspected pathogen must be grown in pure culture
koch’s third postulate
suspected pathogen must be reisolated and shown to be the same as the original
koch’s postulates today
- apply for diseases that have an appropriate animal model
- remain “gold standard” in medical microbiology (even though not all of the them apply all the time)
- animal models not always available
koch found that solid media provided ________
a simple way of obtaining pure cultures (potato slices to gelatin and agar)
microbial diversity
field that focuses on non-medical aspects of microbiology
enrichment culture technique
microbes isolated from natural samples in a highly selected fashion by manipulating nutrient and incubation conditions
chemolithotrophy
oxidation of inorganic compounds linked to energy conservation
in 20th century, microbiology developed in two distinct directions ________ and ________
applied, basic
molecular microbiology
fueled by genomics revolution
subdisciplines of applied microbiology
medical microbiology, immunology, agricultural and industrial microbiology, aquatic and marine microbiology, soil microbiology, microbial ecology
biotechnology
subfield of molecular microbiology, manipulation of cellular genomes, DNA from one organisms can be inserted into a bacterium and the proteins encoded by that DNA harvested
genomics
study of all the genetic material (DNA) in living cells
transcriptomics
study of RNA patterns
proteomics
study of all proteins produced by cell(s)
metabolomics
study of metabolic expression in cells
