Monera Flashcards
what size are they
microscopic
are they uni or multicellular
uni
are they prokaryotic or eukaryotic
prokaryotic (no nucleus or membrane bound organelles
what is their habitat
Occupy wide range of habitats - aquatic,terrestrial
how are they classified
based of on shape
what are the 3 shapes they are classified on
round, rod, spiral
what shape is Staphylococcus
round
what shape is E. coli
rod
what shape is cholera
spiral
what is a bacterias nuclear material
single chromosome of DNA
what is the function of the plasmid
contains DNA that enables resistance
do they have a cell wall?
yes
what is the capsule
slime layer for added protection
what is the flagella
tail like structure that allows for movement
what method of asexual reproduction does bacteria use?
binary fission
describe the process of binary fission
chromosome attaches to cell membrane and replicates.
Cell elongates and divides producing 2 identical daughter cells.
Reproduction very rapid - some reproduce every 20
mins
how do bacteria become resistant
New mutations can spread very quickly allowing bacteria to evolve resistance to antibiotics
what is an endospore
In unsuitable conditions (unsuitable temperature, pH, oxygen saturation the bacterial chromosome can develop a tough outer wall (endospore) allowing it to remain dormant for a long time called an endospore
How does an endospore work?
- Chromosome replicates and endospore forms around one loop of on,
- Parent cell disintegrates leaving the endospore which can with stand extreme temperatures, pH, oxygen levels.
- When conditions are favourable the endospore absorbs water and breaks down and the bacterium forms again.
what are the 2 main types of nutrition
-Autotrophic - organisms which make their own food
- Heterotrophic - organisms which take in food made by other organisms
what are the 2 types of heterotrophic nutrition
saprophytic
parasitic
saprophytic
(feed on dead sources, e.g. bacteria of decay)
parasitic
take food from live host,
what are the 2 types of autotrophic nutrition
PHOTOSYNTHETIC
CHEMOSYNTHETIC
CHEMOSYNTHETIC
(use energy from chemical reaction e.g. nitrifying bacteria)
photosynthetic
(use light,
e.g. purple sulfur bacteria)
Factors affecting the growth of bacteria:
- Temperature - most have optimum 20-30°C but there are some who prefer 0-90°C
- Oxygen concentration -
- pH = most operate at pH 7 and their enzymes become denatured outside that.
- External solute concentration - if external solute concentration is higher, osmosis occurs.
looses water + shrivel up and die in highly concentrated solution - Pressure - high pressure is a limiting factor for bacteria
Facultative anaerobes -
- survive with/without oxygen
Obligate anaerobes
can only survive in the absence of oxygen
beneficial vs harmful uses of bacteria
Beneficial bacteria-›nsulin
* Bacteria such as Lactobacillus are used to convert milk to products such as cheese and yoghurt
“ Genetically modified bacteria e.g. E. Coli are used to make products such as insulin, enzymes, drugs, food flavourings
and vitamins
Harmful bacteria -›food spoilage
* Micro-organisms that cause disease are called pathogens
* Pathogenic bacteria cause disease in plants
* Food spoilage
* Disease in animals
antibiotics
substances produced by micro -organisms that stop the growth of, or kill, other micro-organisms without damaging human tissue.
uses of antibiotics
Used to control fungi and bacteria NOT VIRUSES
causes of antibiotic resistance
. Bacteria can develop immunity (resistance) to
antibiotics by mutations
* Multi-resistant bacteria have evolved that are not affected by most antibiotics.
*not finishing a course of antibionics
how does the overuse of antibiotics contribute to antibiotic resistance
results in the increased growth of antibiotic resistant bacteria
failure to complete a round of prescribed antibiotics allows for the bacteria to survive and regrow
why is the flu not effected by antibiotics
Flu = virus therefore cannot be treated by antibiotics
- Antibiotics only treat bacterial infections
what are the 5 stages of the growth curve in bacteria
lag
log
stationary
decline
survival
describe the lag phase
- no increase in numbers - bacteria adjust to environment
describe the log phase
- numbers increase very rapidly - optimum conditions allow optimum growth
describe the stationary phase
no increase in numbers - growth rate balances with death rates - same no of births as deaths
describe the decline phase
rapid fall in numbers - not enough resources to support growth
describe the survival phase
- some bacteria survive as spores
Batch culture
- A certain amount of nutrient is added to the micro-organisms in a bioreactor
The bacteria go through the lag, log and stationary stages of growth - The process is stopped
- The bioreactor is emptied and sterilised so that the process can be repeated.
Continuous flow culture
- Nutrients are continuously added to the bioreactor
- Bacteria and product are continuously removed
- The bacteria are maintained at the log stage of growth
- Conditions in the bioreactor are kept constant.
which is used more often? batch or continuous flow
Batch culture is used more often
Pathogen
disease causing organisms
why do children get sick more often than adults
Young children have less exposure to disease Making them more susceptible to infection
