Taxonomy Flashcards
How do light microscopes work?
Uses photons, bright light is focused and condensed to pass through an object
Name the 3 types of light microscopes
- Compound bright-field: most common
- Stereo / Dissecting: Larger working distance
- Phase contact: changes the light do that some parts of an object seem bigger
What are the advantages of light microscopes? (4)
- Can use live specimen
- Can use in vivo staining techniques –> to observe uptake of pigments by cells
- cheap
- Useful in education and medicine
What is magnification?
It is when you make an object appear bigger - most light microscopes can magnify greater that 1000x
What is resolution?
the ability to distinguish between objects
How do electron microscopes work?
- Have a greater magnification
- Use beams of electrons and electronically magnify the image
- Electrons have a shorter wavelength than visible light and thus they can pass between and bounce off objects
What are the types of electron microscopes?
- SEM - scanning electron microscope
2. TEM - Transmission electron microscope
What are the advantages of electron microscopes?
- very high magnification: 2,000,000x
- used to view cell parts, microorganisms
What are the disadvantages of electron microscopes?
- very expensive
- require high level of skill
- subject to vibrations
- specimen is often destroyed
- sample must be viewed in a vacuum - the air will scatter the electrons
What are the tasks of living cells?
- Obtain food and energy
- Convert energy into a usable form in the cell
- Construct cell structures
- Chemical reactions
- Eliminate wastes
- Reproduce
What are organelles?
A specialized structure within a cell with a specific function ie. nucleus
what is a prokaryotic cell?
a cell that lacks a nucleus or other membrane bound organelle ie. some bacterial cells
What is a eukaryotic cell?
A cell that contains a nucleus and organelles
What type of cells belong to multi cellular organisms?
Eykaryotic
What is taxonomy?
“the science of classifying organisms” Sorting species into groups based on similar structural features - the more similar the closer the relationship
What is Binomial Nomenclature?
- a method of naming organisms by using a two part name
1. Genus - a small group of related species
2. Species - a group of organisms that look a like and can interbreed
What are the 6 kingdoms?
- animalia
- Plantae
- Protista
- Fungi
- Eubacteria / Monera
- Archaebacteria
What are the characteristics of Animalia and Plantae?
Multi cellular, reproduce sexually, primarily terrestrial
What are the characteristics of Fungi and Protista?
reproduce sexually and asexually, like moist habitats
What are the characteristics of Eubacteria and Archaebacteria?
prokaryotic, autotrophs or heterotrophs, reproduce asexually,
What is the Linnaean system of classification?
Kingdom Phylum Class Order Family Genus Species
What is phylogeny?
hypothesis about the evolutionary history of groups of organisms
What are characteristics of archaebacteria?
- prokaryotic
- unicellular
- autotrophs or heterotrophs
- asexual
- cell wall is chemically unique (contains fats)
- live in extreme conditions
What are the characteristics of prokaryotic cells? (9)
- Small (1-10 um)
- DNA is circular
- Only 1 chromosome
- Cell division by binary fission
- no meiosis, transfer DNA by pili
- asexual reproduction common
- no membrane bound organelle
- most are anaerobic
What are the 3 types of archaebacteria?
- Methanogens
- Give off methane as a waste product
- live on the surface of swamps and marshes, in the intestines of herbivores - Halophiles
- Live in very salty environments 15% salt
- can’t live in weaker salt conditions
- make purple red scum on the surface of water - Thermoacidophiles
- Live in extremely hot and acidic environments
- Hot springs, near volcanoes, deep sea vents
What are the characteristics of Eubacteria?
- AKA Monera
- Prokaryotic
- autotropic / heterotrophic
- reproduce asexually
- live nearly everywhere
- can cause disease
What is an autotroph?
an organism that can produce it’s food
What is a phototroph?
use light as their energy source
What is a Chemotroph?
use chemical compounds as an energy source
What is a heterotroph?
an organism that has to find its food from another source
What is a saprotroph?
an organism that feeds on dead organisms or organic waste
What does aerobic mean?
Requires gaseous oxygen for their growth and metabolism
What does anaerobic mean?
does not require gaseous oxygen for growth
What are obligate anaerobes?
die when exposed to oxygen
facultative anaerobes
can grow in either in the presence of absence of oxygen
Gram positive bacteria
hold a purple dye
Gram negative bacteria
release the dye, appear clear of counter stained
What are the different shapes to classify bacteria
coccus/cocci - sphere Bacillus/bacilli - rod Spirillium - spiral Vibrio - coma Spirochete (tightly coiled)
What are the different arrangements to classify bacteria
Single Diploid (doubles) Tetrad (groups of 4) Sarcina (groups of 8) Strepto (chains) Staphylo (Random)
How do you classify bacteria other than shape and arrangement?
size
presence / absence of flagella, pili, capsules, endospores
location: where it came from
Suceptibiity to attack: viruses, immune system etc.
What are the types of bacterial asexual reproduction? (2)
Budding
Binary fission
What is the process of binary fission?
- DNA replication
- Cell elongates
- walls of the cell are pinched inward (creating septum)
- septum formation is complete
- The cells separate
Lag phase
bacteria adapt themselves to their new habitat; there is no increase in the number of cells
Exponential growth phase
number of cells increase in linear fashion
Stationary phase
bacteria cannot grow anymore due to various changes which have taken place in the culture (eg. lack of oxygen or incorrect pH)
Death phase
eventually cells die, but you can’t tell the difference between dead and living
doubling time
it is a common measurement in bacteria cultures - the time it takes a culture to double
What are the 3 ways sexual reproduction occurs in bacteria?
- Transformation
- Transduction
- Conjugation
Transformation
free DNA make it’s way though a bacterial cell wall and (with the help of enzymes) joins the bacterial genome
Transduction
- virus infection of bacterium
- DNA from the virus is injected into the bacterium and, becomes incorporated into the DNA loop
Conjugation
Donor cells sends out pilus through which it sends part of its DNA
Donor DNA incorporated into receivers DNA
What is the significance of bacterial genetics
- study antibiotic resistance
- genes can e cut out and inserted into DNA ie. frost resistance
- can insert genes into humans ie. insulin, hormone
Pathogen
a disease causing agent such as bacteria
Virus
a particle that contains strands of DNA and RNA cells surrounded by a protective protein coat and that act as mobile genes that can parasitize
How are viruses classified?
classified according to the diseases that they cause and the method of reproduction:
lytic cycle
lysogenic cycle
retroviruses
Lytic cycle
- quick replication within host cell
- symptoms of illness appear in a few days
- eg. influenza
Lysogenic cycle
- host cell incorporates viral DNA into its genome to create a new genome
- at some point in the future viral DNA may cause the lytic cycle tp begin
- the virus remains latent , it may hide for years
Retroviruses
use specialized type of lysogenic cycle
major difference: do not contain DNA, RNA instead
viruses have a special enzyme called reverse transcriptase which can change RNA to DNA
eg. rabies, HIV
Sepsis
Infection
Septic
describes people with infection
antiseptic
against infection
autoclave
pressure cooker used to sterilize equipment
chemotherapy
use of chemicals to combat disease
How do infections spread
animals
insects
humans
water
pandemic
worldwide epidemic
Characteristics of plant-like protists
autotrophs
contain chlorophyll - preform photosynthesis
in in darkness they can be animal like and engulf solid food
examples: algae
What are the differences between fungi and plants
fungi: contain many nuclei per cell heterotrophic no storage molecules no roots dont reproduce by seeds
