Intoduction to Microbiology Flashcards
Microbiology revolves around two themes:
Understanding basic life processes
Applying that knowledge to the benefit of humans
The importance of microorganisms
• Oldest form of life
• Largest mass of living material on Earth
• Carry out major processes for biogeochemical cycles
• Can live in places unsuitable for other organisms
• Other life forms require microbes to survive
A dynamic entity that forms the fundamental unit of life
Cell
Elementsofmicrobialstructure
- Cytoplasmic (cell) membrane
- Cytoplasm
- Ribosomes
- Cell wall
Barrier that separates the inside of the cell from the outside environment
Cytoplasmic (cell) membrane
Aqueous mixture of macromolecules, ions, and ribosome
Cytoplasm
Protein-synthesizing structures
Ribosomes
Present in most microbes; confers structural strength
Cell wall
• No membrane-enclosed organelles, no nucleus
• Generally smaller than eukaryotic cells
Prokaryotes
• DNA enclosed in a membrane-bound nucleus
• Cells are generally larger and more complex
• Contain organelles
Eukaryotes
A cell’s full complement of genes
Genome
Prokaryotic cells generally have a single, circular DNA molecule called a
Chromosome
Its has 4.64 million base pairs and 4,300 genes
Escherichia coli genome
It has 1,000✕ more DNA per cell than E. coli and 7✕ more genes than E. coli
Human cell
Characteristicsoflivingcells
- Metabolism
- Reproduction
- Differentiation
- Communication
- Movement
- Evolution
It is the chemical transformation of nutrients
Metabolism
It is the generation of two cells from one
Reproduction
It is the synthesis of new substances or structures that modify the cell (only in some microbes)
Differentiation
It is the generation of, and response to, chemical signals (only in some microbes)
Communication
via self-propulsion, many forms in microbes
Movement
genetic changes in cells that are transferred to
offspring
Evolution
protein catalysts of the cell that accelerate chemical reactions
Enzyme
DNA produces RNA
Transcription
RNA makes protein
Translation
The link between cells as machines and cells as coding devices
Growth
common ancestral cell from which all cells descended
Last universal common ancestor (LUCA)
The process of change over time that results in new varieties and species of organisms
Evolution
• Evolutionary relationships between organisms
• Relationships can be deduced by comparing genetic information in the different specimens
Phylogeny
___________ is is excellent for determining phylogeny
Ribosomal RNA (rRNA)
ComparativerRNAsequencinghasdefinedthreedistinctlineages of cells called _______
Domains
Three distinct lineage of cells:
• Bacteria (prokaryotic)
• Archaea (prokaryotic)
• Eukarya (eukaryotic)
Archaea later diverged to form two domains:
• Archaea
• Eukarya
From the last universal common ancestor (LUCA), evolution proceeded to form two domains:
• Bacteria
• Archaea
Microorganisms exist in nature in populations of interacting assemblages called
Microbial communities
The environment in which a microbial population lives is its___________
Habitat
_____refers to all living organisms plus physical and
chemical constituents of their environment
Ecosystem
______ is the study of microbes in their natural environment
Microbial ecology
______ are bacteria and archaea that can grow in the extremely harsh environments
Extremophiles
What is the pH and cell count of the stomach?
PH 2, 104 cells/g
What is the pH and cell count of the small intestines?
Ph 4-5,up to 108 cells/g
What is the pH and cell count of the large intestines ?
Ph 7, about 10^11 cells/g
Genetic engineering of microbes to generate products of value to humans, such as insulin
Biotechnology
Example of these are methane, ethanol, and hydrogen
Biofuels
Cleaning up pollutants
Bioremediation
- the first to describe microbes
- Illustrated the fruiting structures of molds
RobertHooke(1635–1703)
the first to describe bacteria
Antoni van Leeuwenhoek (1632–1723)
founded the field of bacterial classification and discovered bacterial endospores
Ferdinand Cohn (1828–1898)
are simplified forms of the bacteria, consisting of the DNA genome, some small amount of cytoplasm, and a specialized coating that confers resistance to heat, radiation, and other harsh external conditions
Endospores
• Discovered that living organisms discriminate between optical isomers
Louis Pasteur (1822–1895)
• Discovered that alcoholic fermentation was a biologically mediated process (originally thought to be purely chemical)
Louis Pasteur (1822–1895)
• Disproved theory of spontaneous generation
Louis Pasteur (1822–1895)
What was the disproved theory that led to the development of methods for controlling the growth of microorganisms?
theory of spontaneous generation
• Developed vaccines for anthrax, fowl cholera, and rabies
Louis Pasteur (1822–1895)
• Demonstrated the link between microbes and infectious diseases
Robert Koch (1843–1910)
Identified causative agents of anthrax and tuberculosis
Robert Koch (1843–1910)
• Koch’s postulates
• Developed techniques (solid media) for obtaining pure cultures of microbes, some still in existence today
Robert Koch (1843–1910)
Awarded Nobel Prize for Physiology and Medicine in 1905
Robert Koch (1843–1910)
Observed that masses of cells called ____________ have different shapes, colors, and sizes
Colonies
• Field that focuses on nonmedical aspects of microbiology
• Roots in 20th century
Microbial diversity
• Developed enrichment culture technique
Martinus Beijerinck (1851–1931)
What do you call the technique where microbes can be isolated from natural samples in a highly selective fashion by manipulating nutrient and incubation conditions
enrichment culture technique
Proposed concept of chemolithotrophy
Sergei Winogradsky (1856–1953)
It is the oxidation of inorganic compounds linked to energy conservation
Chemolithotrophy
Demonstrated that specific bacteria are linked to specific biogeochemical transformations
Sergei Winogradsky (1856–1953)
In the 20th century, microbiology developed in two
distinct directions:
Applied and basic
Fueled by the genomics revolution
Molecular microbiology
Major subdisciplines of applied microbiology
- Medical microbiology
- Immunology
- Agricultural microbiology
- Industrial microbiology
- Aquatic microbiology
- Biotechnology
infectious diseases
Medical microbiology
immune system
Immunology
microbes associated with soil
Agricultural microbiology
production of antibiotics, alcohols, and other chemicals
Industrial microbiology
water, wastewater, and drinking water
water, wastewater, and drinking water
products of genetically engineered microorganisms
Biotechnology
Basic science subdisciplines in microbiology
• Microbial systematics
• Microbial physiology
• Microbial ecology
• Microbial biochemistry
• Bacterial genetics
• Virology
The science of grouping and classifying microorganisms
Microbial systematics
Study of the nutrients that microbes require for metabolism and growth and the products that microorganisms generate
Microbial physiology
Study of microbial diversity and activity in natural habitats
Microbial ecology
Study of microbial enzymes and chemical reactions
Microbial biochemistry
Study of heredity and variation in bacteria
Bacterial genetics
Study of viruses
Virology
study of all of the genetic material (DNA) in living cells
Genomics
study of RNA patterns
Transcriptomics
study of all the proteins produced by cell(s)
Proteomics
study of metabolic expression in cells
Metabolomics