Lecture 2 - The Microbial World Importance Flashcards
life forms too small to be seen by the human eye
Microorganisms
Microorganisms are diverse in ___
form/function
Microorganisms __ every environment that supports life
inhabit
Microorganisms live in __ __
microbial communities
Microorganisms are the __ __ of life
oldest form
MIcroorganisms make up __ __ of Earth’s __
- major fraction
- biomass
living compartment that interacts with the enviornment and others
cell
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
prokaryotes have no ____ compartments (__), and no __
- membrane-enclosed (organelle)
- nucleus
In Prokaryotic Cells:
DNA is not enclosed with __ __
nuclear membrane
In Prokaryotic Cells:
a __ __ chromosome
singular circular
In Prokaryotic Cells:
__ associated with __ proteins
- not
- histone
In Prokaryotic Cells:
cell walls usully contain __, a complex polyssacharide, or __ or __
- peptidoglycan
- psuedopeptidoglycan
- S-layer
In Prokaryotic Cells:
divide by __ __
binary fission
In Eukaryotic Cells:
DNA is enclosed with a __ __
nuclear membrane
In Eukaryotic Cells:
__ __ chromosomes
several linear
In Eukaryotic Cells:
Associated with __ and other proteins
histones
In Eukaryotic Cells:
Divide by __
mitosis
a cell’s full completement of genes
genome
confer special properties in prokaryotes
plasmids
What are the properties of microbial cells
- metabolism
- growth
- evolution
- differentiation
- communication
- genetic exchange
- motility
cells take up nutrients, transform them, and expel wastes
metabolism
replication, transcription, translation
genetic
genetic
replication, transcription, translation
energy, biosyntheses
catalytic
nutrients from the environment are converted into new cell materials to form new cells
growth
cells evolve to display new properties
evolution
capture evolutionory relationships
phylogenetic trees
some cells can from new cell structures such as a spore
differentiation
- have thick walls
- can resist high temperatures, humidity, and other environmental conditions
Spores
cells interact with each other by chemical messengers
communication
cells can exchange genes by several mechnisms
genetic exchange
some cells are capable of self-propulsion
motility
earth is __ __ years old
4.6 billion
first cells appeared between __ and __ __ years ago
3.8 and 4.3 billion
no O2
anoxic
When did the first anoxygenic phototrophs appear
Approx. 3.6 billion years ago
plants and animals appeared approx. __ __ years ago
0.5 billion
at its origin, earth was __
sterile
began the slow oxygenation of earth
cyanobacteria
cyanobacteria appeared about __ __ years ago
3 billion
current levels of O2 in the atmosphere were not achieved until ____ __ years ago
500-800 million
three domains of cellular organisms
- bacteria
- archaea
- eukarya
__ and __ diverged long before eukaryotic cells appear in fossil record
- Archaea
- Eukarya
live in habitats too harsh for other life forms
extremophiles
refers to all living organisms plus physical and chemical constituents of their environment
ecosystem
study of microbes in their natural environment
microbial ecology
Contribution of microbial cells to global biomass:
Carbon
20% microbial
80% plant
major cellular sources using carbon
- plant cell walls
- protein
- RNA
- DNA
- membranes
- peptidoglycan
Contribution of microbial cells to global biomass:
Nitrogen
80% microbial
20% plant
major cellular sources using nitrogen
- protein
- RNA
- DNA
- peptidoglycan
Contribution of microbial cells to global biomass:
Phosphorus
80% microbial
20% plant
major cellular sources using phosphorus
- RNA
- DNA
- membranes
Extreme high temperature
Hyperthermophile
Extreme low temperature
Psychrophile
Extreme low pH
Acidophile
Extreme high pH
Alkaliphile
Extreme pressure
Barophile (piezophile)
Extreme Salt (NaCl)
Halophile
process in which an organism transfers genetic material to another organism that is not its offspring
horizontal gene transfer
What are three mechanisms of horizontal gene transfer?
- transformation
- transduction
- conjugation