Classification of Microbes Flashcards
hierarchy of biological organization
organism - organ system - organ - tissue - cell - organelle - cellular infrastructure - macro-molecules - organic monomers
organism
a single living thing (may be single-celled or multi-cellular)
organ system
a collection of organs that share a common function (e.g. digestive system)
organ
a specialized structure formed of one or more tissues (e.g. the small intestine)
tissue
a collection of specialized cells (e.g. the mucosa (lining) of the small intestine)
what is a cell
a cell is the basic functional and structural unit of all living things
important functions of the cell
- provide structure for the body
- take in nutrients from food and convert them into energy
- carry out specialized functions
-contain the body’s hereditary material and can make copies of themselves
enzymes are
- large complex molecules (usually proteins) that catalyze metabolic reactions
- a catalytic protein
lysozyme
an enzyme that degrades peptidoglycan (bacterial cell wall)
enzymes speed up
metabolic reactions
catalyst
is a chemical agent that speeds up a reaction without being consumed by the reaction
proteinase
digests protein (aka protease)
DNAse
digests DNA
ATP synthase
synthesizes ATP
collagenase
used by some pathogenic bacteria to break peptide bonds in collagen (connective tissue)
reverse transcriptase
used by HIV virus to transcribe its RNA genome to DNA
DNA replication
a DNA genome is copied
transmission of information in cells
DNA - RNA - Proteins
transcription
- an RNA copy of a gene is made
- RNA is made using a DNA template
translation
- the RNA sequence is used to make a polypeptide (sequence of amino acids = a protein)
- the ribosome translates the code from the ‘language’ of nucleotides (RNA) to the language of amino acids (proteins)
DNA replication main enzyme
DNA polyamerase
the enzyme involved in transcription
RNA polyamerase
three domains of life
eukarya, archaea, bacteria
what is a species
- species is Latin for “kind” or appearance
- generally speaking, a species is defined as a population whose members can interbreed to produce viable, fertile offspring
species
classification based on physical, metabolic and genetic characteristics
strain
a genetic subtype of a microorganism
serotype (serovar)
a distinct variation within a species distinguished by characteristic antigens (surface molecules on a cell recognized by the immune system)
variant
a subtype that is genetically distinct from a reference organism, but not sufficiently different to be termed a distinct strain
binomial nomenclature system
- itallicized or underlined
- each organism has two names: Genus and species
- Genus (capitalized), species (lowercase)
virus nomenclature
species name = disease/descriptor virus (e.g. rabies virus)
living organisms include
- prokaryotes (bacteria, archaea)
- eukaryotes (fungi, animal parasites)
non-living organisms include
replicating viruses and prions, and non-replicating toxins
prokaryotes- archaea
no known pathogens
prokaryotes- bacteria
- ‘simple’ single-celled organisms
- no nucleus or internal organelles
- most posses a cell wall containing peptidoglycan
eukaryotes
- have a nucleus
- single-celled and multi-cellular organisms
eukaryotes- animalia
- multicellular, ingest nutrients
- sponges, worms, vertebrates and invertabrates
- no cell wal
eukaryotes- plantae
- multicellular, photosynthetic
- mosses, ferns, conifers, flowering plants (some algae)
eukaryotes- fungi
- absorb nutrients, form hyphae if multicellular
- yeasts, molds, mushrooms
- cell walls containing chitin
eukaryotes- protists (protozoa)
- unicellular organisms
- not easily categorized
viruses and prions- non-living infectious agents
cannot reproduce on their own
virus
nucleic acid coated in protein (and sometimes membrane)
prion
proteins gone bad
viral species
population of viruses with similar characteristics and that occupy a particular ecological niche
toxins- non-living, non-infectious disease agents
- not cellular, so are not classified in hierarchical system
- they can cause adverse health in humans, animals or plants
toxins can be
produced by microorganisms such as bacteria and fungi, or other living organisms such as plants and animals
plasma/ cell membrane
the membrane found in all cells that separates the interior of the cell from the outside environment.
nucleus
the membrane-enclosed organelle within a cell that contains the chromosomes
cell wall
a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mechanism.
cilia/flagella
are motile cellular appendages found in most microorganisms and animals, but not in higher plants. In multicellular organisms, cilia function to move a cell or group of cells or to help transport fluid or materials past them.
ribosome
an intercellular structure made of both RNA and protein and it is the site of protein synthesis in the cell
lysosome
a membrane-bound cell organelle that contains digestive enzymes
