20 - Monera (bacteria) Flashcards
Bacterial types
Round
Rod
Spiral / vibrio
Round
Found in pairs, chains or clusters
Pneumonia
Sore throat
Food poisoning or skin boils
Rod
May contain spores
Tuberculosis
Tetanus
Botulism
Spiral
Called vibrio when shaped like a comma
Syphilis
Cholera (vibrio)
Reproduction
Reproduce asexually by a method called binary fission.
DNA strand copies itself at a certain size
Now two identical strand of DNA
Cell elongates with a strand of DNA attached to each end
Finally the cell splits into two similar sized cells.
Bacteria can divide every 20 minutes if conditions suitable this means a single bacteria could produce over 1 million bacteria in seven hours
Mutations in bacteria
Bacteria reproduce asexually their offspring are genetically identical they can evolve very fast due to the speed which new mutations can spread. (Resistance to new antibiotics)
Endospores
Bacteria can withstand harsh and unfavourable conditions by producing endospores.
Form when bacterial chromosome replicates with one of the new strands becoming enclosed by a tough walled endospore
Inside the parent cell
Parent cell breaks down and endospore remains dormant for a long time
When conditions are suitable, endospore absorbs water and the tough wall breaks down.
Chromosome is copied and a normal bacterium forms again which can then reproduce by binary fission.
Endospores are difficult to kill, withstand lack of food, water, most poisons and high temperatures.
Nutrition
The way an organism gets its food
Autotrophic
An organism that makes its own food with
Sources:
>Sun - photosynthesis
>Chemical reactions - chemosynthesis
Types of bacteria:
>Photosynthetic (use light e.g purple sulfúrico bacteria)
>Chemosynthetic (use energy from chemical reactions e.g nitrifying bacteria)
Photosynthetic bacteria have chlorophyll on membranes use the same type of light as plants.
Chemosynthesis
Production of food using energy released from chemical reactions
Heterotrophic
An organism takes in food made by other organisms
Bacteria types:
>saprophytic (feed on dead sources e.g bacteria of decay)
>parasitic (take food from live host e.g disease-causing bacteria)
Saprophytes
Organisms that take in food from dead organic matter
Parasites
Organisms that take food from a live host and usually cause harm
Factors affecting the growth of bacteria
Temperature Oxygen concentration pH External solute concentration Pressure
Factors affecting the growth of bacteria - Temperature
Grow well at 20 degrees C and 30 degrees C
Can tolerate much higher temperatures without being denatured
Low temps slow down the rate of bacterial growth
Factors affecting the growth of bacteria - Oxygen concentration
Aerobic bacteria require oxygen for respiration low concentration of oxygen slow down bacterial growth
E.g streptococcus - sore throat bacteria
Anaerobic bacteria doesn’t require oxygen to respire.
E.g Clostridium - tetanus or botulism
Facultative anaerobes can respire with or without oxygen
E.g Escherichia Coli found in intestines
Obligate anaerobes can only respire in the absence of oxygen
E.g Clostridium tetani - tetanus
Factors affecting the growth of bacteria - pH
Unsuitable pH = denatured
Most grow at neutral pH 7
Some can tolerate very low (acidic) or very high (alkaline) pH values
Factors affecting the growth of bacteria - External solute concentration
Bacteria gain or lose water by osmosis
higher solute - dehydrates
lower solute - water will enter the bacteria the cell walls of bacteria can normally prevent bacterial cells from bursting
most bacteria live in less concentrated solutions
Factors affecting the growth of bacteria - pressure
Bacterial walls are not strong enough to withstand the high-pressure however some such as those found in deep sea vents can
Economic importance of bacteria - benefits
Convert milk to products such as butter yoghurt and cheese
production of vinegar silage pickles and antibiotics
genetically modified bacteria used to make insulin drugs enzymes amino acid’s vitamins food flavourings alcohols and a growing range of new substances
Economic importance of bacteria - disadvantages
Cause food to decay for example they cause milk to turn sour
cause human animal and plant diseases such as tuberculosis Whooping cough septic throat meningitis typhoid cholera Diphtheria Dysentery food poisoning Mastitis Brucellosis
Antibiotics
Used to control bacterial infection can treat some fungal diseases do not affect viruses
Produced by genetically engineered bacteria for example streptomycin, neomycin and tetracycline
Pathogenic bacteria
Cause disease
Antibiotics definition
Chemicals produced by microorganisms that stop the growth or kill other microorganisms without damaging human tissue
Antibiotic resistance
Antibiotic resistance bacteria have developed by mutations not affected by the antibiotics being used new antibiotics must be produced to continually to treat new resistant bacteria
Gene for antibiotic resistance located on a plasmid pass copies of their plasmid onto other bacteria,in this way antibiotic resistance can pass from one bacteria to another
Bacterial strains that are resistant to almost all known antibiotics are said to be multi-resistant
Potential abuse of antibiotics in medicine
Overuse of antibiotics in medicine results in increased growth of antibiotic resistant bacteria
this can happen when doctors prescribe antibiotics unnecessarily like for virus infections
and the failure of some patients to complete their treatment of antibiotics, allows the bacteria to survive and regrow
Bacteria are prokaryotes
Bacteria belong to the kingdom monera
prokaryotes are organisms that lack a membrane enclosed nucleus or membrane enclosed cell organelles such as mitochondria and chloroplasts
Apart from the kingdom monera all other kingdoms contain eukaryotes
Lag phase a
Numbers remain constant adopting themselves to their new environment producing new enzymes to digests the nutrients in which they are to grow
Log phase b
Bacterial numbers increase rapidly reproducing at their maximum rate the number of bacteria is doubling in every new generation this is as a result of ideal conditions food moisture space or oxygen
also called the exponential phase
Stationary phase c
There is no increase in bacterial numbers production of new bacteria is compensated for by the death of equal numbers
rate of growth slows down because of lack of food space moisture oxygen and the buildup of toxic waste products
Decline phase d
In the decline or death phase the number of bacteria falls rapidly the death rate is greater than the rate of reproduction
slow rate of reproduction caused by the same factors as in the stationary phase
Survival phase e
A small number of bacteria survive by remaining dormant as spores which can survive for a long time by remaining dormant until conditions are suitable again
Food processing
Production of useful products using enzymes include dairy products such as yoghurts and cheese is artificial sweeteners amino acid’s vitamins flavourings flavour enhancer is an alcohol products such as wines and beers this is called single cell production there are two main methods of production batch culture or fermentation and continuous flow culture or fermentation
Batch culture
Fixed amount of sterile nutrient is added to the micro organisms in the bioreactor
Other conditions include suitable temperatures pressure aeration and pH the micro organisms go through the lag the log and the stationary but rarely decline and survival stage
As this happens the nutrients are used up and the product is formed
At the end of production the bioreactor is emptied separated from the solution and purified the bioreactor is cleaned resterilised and the process is repeated
Continuous flow continuous flow
Nutrients are continuously fed into the bioreactor
culture medium continuously withdrawn at same time
volume of material in the bio reactor remains constant
microorganisms maintained more or less constantly in the log stage of growth
they are growing rapidly and producing the product at a fast pace
Factors such as PH temperature the rate of stirring and the concentrations of nutrients oxygen and waste products are kept constant
maintaining constant conditions is very difficult for this reason continuous flow processing is limited to a small number of applications
