Exam 1 Flashcards
Germ theory of disease
some diseases are caused by microorganisms that have gained access to the human body
purpose of koch’s postulates
to identify germs with infectious diseases; they became standards for linking a specific organism to a specific disease
Koch’s first postulate
the suspected pathogen must be present in all cases of the disease and absent from healthy animals
Koch’s second postulate
the suspected pathogen must be grown in pure culture
Koch’s third postulate
cells from a pure culture of the suspected pathogen must cause disease in a healthy animal
Koch’s fourth postulate
the suspected pathogen must be reisolated and shown to be the same as the original
two themes of microbiology
- understanding the basic life processes
- applying that knowledge to the benefit of humans
What is microbiology?
microbiology is the study of microscopic life forms, called microorganisms
evolution
the process of change over time that results in new varieties and species of organisms
phylogeny
evolutionary relationships between organisms
Last universal common ancestor (LUCA)
common ancestral cell from which all cels descended
what are viruses composed of and what do they require?
They have a DNA or RNA core surrounded by a protein coat and sometimes a lipid membrane. They require a host to make copies of itself.
what are diversity and the abundances of microbes controlled by?
resources, example nutrients, and environmental conditions like temperature, pH, O2
microbial communities
microorganisms exist in nature in populations of interacting assemblages
nomenclature
gives scientific names to organisms
cytoplasmic (cell) membrane
barrier that separates the inside of the cell from the outside environment
cytoplasm
aqueous mixture of macromolecules, ions, and ribosome
ribosomes
protein-synthesizing structures
genome
an organism’s complete set of DNA, including all of its genes. Each genome contains all of the information needed to build and maintain that organism.
Differences between eukaryotes and prokaryotes
membranes- lipid contents and lipids in prokaryotes do not contain cholesterol unlike eukaryotes, and organelles exist in eukaryotes and. not prokaryotes. Also genomes; prokaryotes have circular chromosomes and eukaryotes do not.
8 True or false? All cells, prokaryote or eukaryote metabolize, grow, and evolve
true
true or false? some cells, prokaryote or eukaryote, are able to differentiate, communicate with other cells, exchange genetic information with other cells, and move
true
enzymes
protein catalysts of then cell that accelerate chemical reactions
DNA replication
DNA chromosome is replicated
transcription
DNA gene is read to produce RNA
Translation
RNA message is read to make protein
What results in growth?
growth is the result of the activities of metabolism; cells use metabolic processes to gain mass, replicate their DNA, and divide
resolution
the smallest distance by which two objects can be separated and still be distinguished
light microscopy
useful for examining cells while they are alive
phase contrast microscopy and differential interference contrast microscopy
exploits the phase of light passing through an object varying thickness and density to produce an image
dark field
illuminating rays are directed from the side, so only scattered light enters the microscope lens
true or false, staining almost always kills the cells
true
What are some uses for a fluorescent microscopy
view a specific cell in a mixture of different cells, and view specific cell components in a cell
morphology
cell shape
coccus (pl. cocci)
spherical or ovoid
rod
cylindrical shape
True or false, morphology typically does NOT predict physiology, ecology, phylogeny, etc.
true
what is the advantage for a cell being small
support greater nutrient exchange per unit cell volume, and tend to grow faster than larger cells
what is the cell wall composed of
peptidoglycan, polysaccharides chains wrapped in circles around cell, and sugar chains
Gram positive
-Capsules
-S-Layer (made of protein)
-Thick cell wall
-Lipoteichoic acids
Gram negative
-Capsule
-Outer Membrane
-Thin cell wall
-Periplasm
-Plasma membrane
Cytoplasmic membrane
surrounds the cell and separates cytoplasm from the environment
hopanoids
pentacyclic chemicals that act to stabilize the bacterial membrane
What is the membrane function
-Permeability barrier
-Protein anchor
-Energy conservation
Integral membrane proteins
firmly embedded in the membrane
Peripheral membrane proteins
one portion anchored in the membrane
Channel (proteins)
Transports solute across membrane. Passive. Often called porins
Carrier (proteins)
Transports solute across membrane. Active or Passive
Receptor (proteins)
Binds extracellular or periplasmic molecules, confirmation change relays information to cell
Enzyme
Facilitates chemical reaction
Nutrient Transport
-Carrier mediated transport systems
-Highly specific
-Three major classes of transport systems in prokaryotes
-All require energy in some form, usually proton motive force or ATP
True or false: carrier transport is faster than simple diffusion
true
Uniporters
transport in one direction across the membrane
Symporters
function as co-transporters
Antiporters
transport a molecule across the membrane while simultaneously transporting another molecule in the opposite direction
Simple transport
driven by the energy in the proton motive force
Group translocation
chemical modification of the transported substance driven by phosphoenolpyruvate
ABC transporter
periplasmic binding proteins are involved and energy comes from ATP
What two types of lipid is the outer membrane of gram negative bacteria made of?
Inner leaflet composed of phospholipid, outer leaflet composed of lipopolysaccharide (LPS)
Fimbriae
Short, helical filamentous protein structure
Capsules and slime layers function
-assist in attachment to surfaces
-protect against phagocytosis
-resist desiccation
Pili
Thin filamentous protein structure