What are the distinguishing features of living organisms?
1) A high degree of chemical complexity and microscopic organization
2) Systems for extracting, transforming, and using energy from the environment
3) Mechanisms for sensing and responding to alterations in their surroundings
4) A capacity for precise self-replication and self-assembly
5) A capacity to change over time by gradual evolution
plasma membrane
defines the periphery of the cell, composed of a lipid bilayer
metabolites
small organic molecules in the cytosol
Name some components of the cytoplasm
cytosol, metabolites, intermediates of biosynthetic and biodegrative pathways, ions, RNA, coenzymes, etc.
proteasomes
degrade proteins no longer needed by the cell
genome
complete set of genes
mycoplasmas
smallest microorganism known today
What are the three domains of life?
Eukarya, Archaea, Bacteria
obligate anaerobes
anaerobes that die in the presence of oxygen
facultative anaerobes
anaerobes that can live with or without oxygen
What do aerobes transfer electrons to to form energy?
oxygen
What do anaerobes transfer electrons to in order to form energy?
nitrate (forms N2), sulfate (forms H2S), or CO2 (forms CH4)
phototrophs
obtain energy from sunlight
chemotrophs
derive their energy from oxidation of a chemical fuel
lithotrophs
oxidize inorganic fuels (HS- to S, S to SO4-, NO2- to NO3-, Fe2+ to Fe3+)
organotrophs
oxidize organic compounds
autotrophs
obtain all needed carbon from CO2
heterotrophs
must obtain carbon from organic nutrients
peptidoglycan
rigid polymer that gives bacteria their rigidity
pseudopeptidoglycan
rigid polymer that gives archaea their rigidity
pili
provide points of adhesion to the surface of other cells
flagella
propels cell through its environment
cell envelope
consists of plasma membrane, peptidoglycan layer, and capsule
plasmid
small circular piece of DNA in the cytosol
differential centrifugation
the sample is centrifuged at a low speed to collect larger cells/cell components and the speed continues to increase each time to get a pellet of a different material
isopycnic centrigugation
the solvent is in different densities (usually with sucrose) and as the sample is centrifuged particles line up at their specific density where each layer can be collected
secondary metabolites
small molecules whose roles play specifically to plant life (only found in plants-these include scent producing molecules and things such as nicotine, morphine, and caffeine
What weight does a molecule need to be to be considered a macromolecule?
~5,000
oligomers
short polymers
What is the largest component of a cell next to water?
proteins
proteome
the sum of all the proteins working in a cell
What are the three major functions of polysaccharides?
1)energy rich fuel stores
2)rigid structural components of cell walls
3)extracellular recognition elements that bind to proteins on other cells
oligosaccharides
shorter polymers of sugars
What is the main function of oligosaccharides
attach to proteins or lipids on the cell's surface and act as specific cellular signals
What are the functions of lipids?
1) structural components of membranes
2) energy rich fuel stores
3) pigments
4) intracellular signals
What are the informational macromolecules
proteins and nucleic acids (named for their large subunit sequences)+ some oligosaccharides
stereoisomers
molecules with the same chemical bonds, but different configuration (arrangement)
stereospecific
cell functions only work with certain steroisomers- not all of them