monera (eg bacteria) Flashcards
what kingdom do bacteria belong to
monera
they are unicellular organisms
why are bacteria also known as prokaryotes
they have no membrane bound nucleus or membrane mound cell organelles
what are the three shapes of monera
spherical (cocci)
rod (bacillus)
spiral (spirillum)
give an example of a spherical bacteria
staphlococcus aureus (causes pneumonia)
streptococcus (causes sore throat)
give examples of rod shaped bacteria
tuberculosis
e. coli
give examples of spiral bacteria
syphilis
cholera
function of cell wall
shape and structure
function of cytoplasm
contains ribosomes and storage granules but no mitochondria or chloroplasts
function of nuclear material
single chromosome of DNA
function of capsule
protection
function of flagella
movement
function of plasmid
circular piece of DNA containing few genes for drug resistance
how do bacteria reproduce
asexually by binary fission
explain the process of binary fission
- the chromosome attaches to the cell membrane and the DNA is replicated
2.the cell elongates and the two chromosomes separate
3.the cell wall grows to divide the cell in two
4.two identical daughter cells are formed
what is an autotrophic organism
an organism which makes their own food
what is a heterotrophic organism
an organism which takes in food made by other organisms
name the two types of autotrophic bacteria
photosynthetic bacteria
-use light energy to make food eg purple sulphur bacteria
chemosynthetic bacteria
-use energy from chemical reactions to make food
eg nitrifying bacteria
name the two types of heterotrophic bacteria
saprophytic bacteria
-live off dead organic matter
eg bacteria of decay in soil
parasitic bacteria
-take food from live host, some cause diseases
eg bacillus anthracis- causes anthrax
name the factors affecting the growth of bacteria
-temperature
-oxygen concentration
-pH
-external solute concentration
-pressure
how does temperature affect bacteria
-most bacteria grow well between 20-30 degrees
-some can tolerate higher temperatures without their enzymes becoming denatured
-low temperatures slow down the rate of reaction of enzymes resulting in slower growth
how does pH affect the growth of bacteria
enzymes will become denatured if in an unsuitable pH
how does oxygen concentration affect the growth of bacteria
-aerobic bacteria require oxygen for respiration eg streptococcus
-this is why oxygen is sometimes bubbled through bioreactors
what are the two types anaerobic bacteria
-facultative anaerobes
can respire with or without oxygen eg e.coli
-obligate anaerobes
can only respire without oxygen eg clostridium tetani (causes tetanus)
how does external solute concentration affect bacteria growth
- bacteria can gain or lose water y osmosis
-if the external solute concentration is higher than the bacterial cytoplasm, water will move out of bacteria (dehydration)
-food preservation techniques are based on this
-if the external solute concentration is lower than the bacterial cytoplasm, solute concentration water will enter the bacteria
-cell wall prevents bursting in most cases
how does pressure affect the growth of bacteria
-the growth of most bacteria is inhibited by high pressures
-some bacteria can withstand high pressures
-pressure tolerant bacteria for use in bioreactors can be formed by genetic engineering techniques
beneficial bacteria
-lactobacillus is used to convert milk products such as cheese and yoghurt
-genetically modified bacteria such as e.coli are used to make products such as insulin, enzymes, drugs, food flavourings and vitamins
what are micro-organisms that cause diseases called`
pathogens
harmful bacteria
-bacillus anthracis causes anthrax in humans
-tuberculosis, typhoid, cholera etc
what are antibiotics
substances produced by micro-organisms that stop the growth of or kill other micro-organisms without damaging human tissue
can be used to control bacterial and fungal infections but do not effect viruses
who created the first antibiotic
sir alexander fleming
penicillin isolated from a fungus
what causes the growth of antibiotic resistant bacteria
-mutations in bacterial genes
-overuse of antibiotics
