Zusammenfassung der Ressource
Bacteria (example of monera)
- What are they:
They are
unicellular
organisms,
prokaryotes (no
membrane
bound nucleus/
organelle)
- They're classified according to 3 shapes: Spherical,
Rod and Spiral. These are all bacterial cells
- Spiral: (spirrillum)
e.g treponema
pallidum (syphillis)
- Spherical: (cocci)
e.g staphylococcus
aureus
(pneumonia and
throat infection)
- Rod: (bacillus)
e.g bacillus
anthracis
(anthrax)
- Always present:
cell wall, cell
membrane,
cytoplasm,
ribosome,
loop of DNA
- cell wall: protects
cell, supports and
strengthens cell
- cell membrane:
retains cell contents
and controls what
passes in and out of
the cell
- cytoplasm:
fluid that
contains cell
organelles
- ribosome: makes protein
- Loop of DNA:
contains genes
that control the
cell
- Sometimes present:
flagella,
capsule(dry or
slime layer(moist)
and plasmid
- flagella: allows cell to move/swim
- capsule/slime layer: prevents water loss
- plasmid: contains genes
- Reproduction
- is asexual
- method is
known as binary
fission
- 1) DNA replicates and
move to each end of
the cell (they elongate)
- 2) Cell membrane
and cell wall pinch
in to form two
separate cells
- 3) Each contains
its own loop of
DNA, they are
known as
daughter cells
- Endospores
- is a tough resistant cell
that forms around one
of the loops of DNA
inside the existing cells
- Can survive unfavourable
conditions
- Conditions for bacterial growth
- Nutrition,
Temperature,
Oxygen,
concentration, pH,
External solute
concentration,
Pressure
- Growth curve:
- A)Lag phase
B)Log phase
C)Stationary phase
D)Decline phase
E)Survival phase
- Lag phase- does not
change as it's reacting to
the new environment
- Log phase- increases
rapidly to reproduce
at the maximum rate
- Stationary phase- does not change as
the bacteria may be short for food,
water, space or oxygen
- Decline phase- falls rapidly
because the death rate is
greater than the reproduction
rate
- Survival phase- small number of bacteria remain dormant as spores
- Food processing
- Batch Food Processing and
Continuous-Flow Food Processing
- Beneficial and Harmful bacteria
- Beneficial: to make
yoghurt and cheese,
genetically engineered
bacteria make enzymes
and hormones
- Harmful: causes food to
decay and pathogenic
bacteria cause diseases such
as pneumonia and tetanus
- Antibiotics
- they are chemicals
produced but micro
organisms that kill or
prevent the growth of
bacteria without damaging
the human tissue
- Antibiotic resistance
- When an antibiotic is first used it kills the bacteria
in the organism. Soon the mutation in one
bacterium will cause that bacterium to be
resistant to the antibiotic
- As all the antibiotic-sensitive bacteria are
killed off, the resistant bacterium has no
competition and can form huge numbers of
resistant bacteria
- Bacteria have developed and resistance
to most known antibiotics. They are
called multi-resistant bacteria
- The over-use of antibiotics has
accelerated the evolution of the
multi-resistant bacteria
- Antibiotics don't kill viruses.
- Examples: penicillin and streptomycin