Lecture 2A: Introduction to the Microbial World Flashcards
Microorganisms (microbes) are:
- diverse in form/function
- inhabit every environment that
supports life - many single-celled, some form
complex structures, some
multicellular - live in microbial communities
Microorganisms, Major Form of Life
- Oldest form of life
- Major fraction of Earth’s biomass
- Associated with plants and animals, and
other life forms - Affect human life (infectious diseases,
food and water, soils, animal health,
fuel)
A living compartment that interacts with the environment and
other cells
The cell
Elements of microbial structure that all cells have in common.
- Cytoplasmic (Cell/ plasma) Membrane
- Cytoplasm
- Ribosome
barrier that separates the
inside of the cell from the outside environment
cytoplasmic (cell/plasma) membrane
matrix of macromolecules, small organics, ions, and
ribosomes inside cell, with water as the major component
Cytoplasm
protein-synthesizing structures
ribosomes
no membrane-enclosed
compartments(organelle), no
nucleus
prokaryotes
Examples of prokayotes
Bacteria and Archaea
- plants, animals, algae, protozoa,
fungi - contain organelles
- DNA enclosed in a membranebound compartment = nucleus
Eukaryotes
Distinguishing Features of Procaryotic Cells:
1. DNA
- Not enclosed within a nuclear membrane.
- A single circular chromosome.
- Not associated with histone proteins.
Distinguishing Features of Procaryotic Cells: Oganelles
-Lack membrane-enclosed organelles like mitochondria, chloroplasts, Golgi, etc.
Distinguishing Features of Procaryotic Cells: Cell wall
-Cell walls usually contain peptidoglycan, a complex polysaccharide, or pseudopeptidoglycan or S-layer
a large polymer that forms a mesh-like scaffold around the bacterial cytoplasmic membrane
peptidoglycan
Distinguishing Features of Procaryotic Cells: Division
Divide by binary fission
- a type of asexual reproduction where a parent cell divides, resulting in two identical cells, each having the potential to grow to the size of the original cell
Binary Fission
Distinguishing Features of Eucaryotic Cells: 1. DNA
DNA is;
- Enclosed within a nuclear membrane.
- Several linear chromosomes.
- Associated with histones and other proteins.
Distinguishing Features of Eucaryotic Cells: Organelles
-Have membrane-enclosed organelles like mitochondria,
chloroplasts, Golgi, endoplasmic reticulum, etc.
Distinguishing Features of Eucaryotic Cells: Division
Divide by mitosis
Mitosis produces two genetically identical “daughter” cells from a single “parent” cell
Mitosis
a cell’s full complement of genes
genome
Eukaryotic DNA
- Linear chromosomes within nucleus
- much larger/more DNA (up to billions of
base pairs)
prokaryotic DNA
- generally single circular chromosome that
aggregates to form the nucleoid region - may also have plasmids
(extrachromosomal DNA) that confer
special properties (e.g., antibiotic
resistance) - mall, compact (0.5
–10 million base pairs)
The properties of microbial cells. Major activities ongoing in
cells in the microbial community
- Metabolism
- Growth
- Evolution
- Differentiation
- Communication
- Genetic Exchange
- Motility
Cells take up nutrients, transform them and expel waste.
Metabolism
Replication, transcription, translation
Genetic
Energy, biosysnthesis
Catalytic
Nutrients from the environment are converted into new cell materials to form new cells
Growth
Cells evolve to display new properties. Phylogenetic trees capture evolutionary relationships
Evolution
Some cells can form new cell structures as spore
Differentiation
Cells interact with each other by chemical messengers
Communication
Cells can exchange genes by several mechanism
Genetic exchange
Some cells are capable of self-propulsion
Motility
First cells appeared between ___ and ___ billion
years ago.
- 3.8 and 4.3 billion years ago
~2.6 billion years ago.
The atmosphere was anoxic (no O2)
A condition in which the aquatic (water) environment does not contain dissolved oxygen (DO)
- anoxic
plants and animals _____ years ago
~0.5 billion years ago
live in habitats too harsh for
other life forms.
Extremophiles
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
________ microbial cells on Earth
~2 x 10^30
Temeprature, High.
- an organism that thrives in extremely hot environments
Hyperthermophile
Temperature, Low.
- a group of organisms with the ability to grow and reproduce under low temperatures
psychrophile
Example of Hyperthermophile
- Methanopyrus kandleri (scientific name pag sulat)
Hyperthermophile, domain and habitat
Domain: Archea
Habitat: Undersea hydrothermal vents
Hyperthermophile, Minimum, optimum and maximum temperature.
Minimum: 90°C
Optimum: 106 °C
Maximum: 122°C^b
psychrophile, domain and habitat
Domain: Bacterial
Habitat: Sea Ice
psychrophile, Minimum, optimum and maximum temperature.
Minimum: -12
Optimum: 5°C
Maximum: 10°C
Are organisms that can withstand and even thrive in acidic environments
Acidophile
microorganisms that grow optimally or very well at pH values (above 9).
Alkaliphile
Example of Acidophile
Picrophilus oshimae (Scientific name page sulat)
Example of Alkaliphile
Natronobacterium gregoryi
Acidophile, domain and habitat
Domain: Archea
Habitat: Acidic Hot springs
Alkaliphile, domain and habitat
Domain: Archea
Habitat: Soda lakes
Acidophile, Minimum, optimum and maximum pH.
Minimum: -0.06
Optimal:0.7^d
Maximum: 4
Alkiliphile, Minimum, optimum and maximum pH.
Minimum: 8.5
Optimal: 10^e
Maximum: 12
are defined as organisms which grow optimally or preferentially at pressures greater than atmospheric pressure
Barophile (piezophile)
Example of Barophile (piezophile)
Moritella yayanosii (scientific name pagsulat)
Barophile, domain and habitat
Domain: Bacteria
Habitat: Deep ocean sediments
Barophile, Minimum, optimum and maximum atm. (atmospheric pressure)
Minimum: 500 atm
Optimum: 700 atm
Maximum: >1000 atm
an organism, especially a microorganism, that grows in or can tolerate saline conditions.
Halophile
example of halophile
Halobacterium salinarum (scientific name pagsulat)
Halophile, domain and habitat
Domain: Archea
Habitat: Salterns
Halophile, Minimum, optimum and maximum saline.
Minimum: 15%
Optimum: 25%
Maximum: 32% (saturation)
