Microbiology Part 2 (2.2) Flashcards
What can organisms and biological entities be catergorised as?
Cellular and Acellular
By what process are prokaryotes able to replicate asexually?
Binary Fission
By what process do single celled eukaryotes replicate asexually?
Mitosis
What are the stages of Mitosis?
- Prophase
- Metaphase
- Anaphase
- Telophase
By what process can single celled eukaryotes replicate sexually?
Meiosis
What are the stages of Meiosis?
- Meiosis 1
- Prophase 1
- Metaphase 1
- Anaphase 1
- Telophase 1
- Meiosis 11
What happens in the process of budding yeast reproduction?
- asexual reproduction via budding
- fusion of two haploid cells to form a diploid cell
- formation of haploid spores via meiosis
Microbes reproduce rapidly. True or False?
True - makes them excellent models for experimental evolution studies.
What are the stages in growth curves? (in a closed system)
- inoculation
- lag phase
- exponential phase
- stationary phase
- decline/death phase
How is metabolism carried out in an energy source?
- phototrophs gain energy from sunlight
- chemotrophs gain energy from inorganic and/or organic compounds
How is metabolism carried out in electron sources?
- organotrophs gain electrons from organic compounds
- lithotrophs gain electrons from inorganic compounds
How is metabolism carried out in a carbon source?
- autotrophs use CO2 to make carbon compounds (primary producers)
- heterotrophs use organic compounds from their environment
What is a niche?
set of environmental conditions where a species of microbe can replicate.
What are some conditions that determine where a microbe can live?
- nutrient availability
- oxygen concentration
- temperature
- pH
- light intensity
- radiation
- solute concentration (osmolarity & water activity)
What is a entailed in a free-living lifestyle?
- it inhabits every type of environment on Earth
- wide range of metabolic capabilities
With a symbiotic lifestyle, what happens in a pathogenic environment?
- interaction with host organism
- host is damaged
With a symbiotic lifestyle, what happens in a mutuallistic environment?
- interaction with host organism
- where both partners benefit
With a symbiotic lifestyle, what happens in a commensal environment?
- interaction with host organism
- one partner benefits
- other is unaffected
What is bacteria?
a single-celled prokaryote
How does bacteria reproduce?
Asexually by binary fission.
What lifestyles does bacteria have?
- free-living
- commensal
- mutualistic
- pathogenic
What can be found in a bacteria?
- no nucleus
- 1 circular chromosome (dsDNA)
- one or more plasmids
What shapes do bacteria usually take on?
- spherical
- rods
- spirals
What is usually found in the cell wall of bacteria?
Peptidoglycan - (gram stains help to identify 2 main groups)
How can you identify a gram positive bacterium?
- peptidoglycan traps crystal violet (iodine stain - purple)
- cells are not decolourised by ethanol wash
- purple stain masks safranin counters
How can you identify a gram negative bacterium?
- crystal violet (iodine stain) = washed away by ethanol wash
- cell = stained red/pink with safranin counterstain
What does a capsule help bacteria do? (produced by some species of bacteria)
- attach to surfaces
- evade the immune response
What do fimbriae help bacteria do?
- being thread-like appendages
- helps to attach to surfaces/ other cells
What is flagellum?
- tail-like appendage that bacteria use to swim through liquid
- rotational movement propels bacteria towards nutrients/ away from toxicants via chemotaxis
What is biofilm?
- aggregation of bacteria that are attached to each other/ and or a surface
- embedded in an extracellular polymeric substance
What is a sex-pilus?
- thread - like appendage that bacteria use to exchange plasmids (bacterial conjugation)
What does Photorhabdus luminescens (bacterium) form?
- forms a mutualistic relationship with nematodes
- with EPN (entomopathogenic nematode)
- infect insect larvae - cause lethal septicaemia
- dead insect larvae glow in the dark
What are archaea and how do they reproduce?
- single- celled prokaryotes
- perform asexual reproduction
- lack peptidoglycan in cell wall
- unique cell membrane lipids
- 1 circular chromosome
- no nucleus
- 1 or more plasmids
What are the forms of archaea?
- spherical
- rods
- spirals
- rectangles
- squares
- lemon - shaped
What the lifestyles of archaea?
- free-living (many are extremophiles)
- commensals
What are fungi and how do they reproduce?
- single - celled & multicellular eukaryotes
- asexual/sexual reproduction
- chitin in cell wall
- multiple linear chromosomes within the nucleus
What are the forms of fungi?
- yeasts
- moulds
What are the lifestyles of fungi?
- decomposers
- mutualistic
- pathogenic
Give one common mould that acts as a decomposer of food.
Penicillium
What are protists and how do they reproduce?
- single - celled & multiceullar eukaryotes
- e.g. slime molds, algae, amoebae
- by asexual/ sexual reproduction
- multiple linear chromosomes with nucleus
What forms do protists exist in?
- unicellular (most)
- multicellular
What are the lifestyles of protists?
- free- living
- pathogenic
- mutualistic
