Download File - I. Reillys Biology Class

Monera
e.g. Bacteria
Section 1
Aidhm
Name 3 types of bacterial cell and their structure
2. Explain reproduction of bacteria
1.
 http://www.britannica.com/EBchecked/media/
106333/Bacteria-exist-in-a-wide-variety-ofshapes-and-sizes
Bacteria in pond water
Bacteria on apple
Bacteria
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Bacteria belong to the kingdom Monera. They are
unicellular organisms
Also known as prokaryotes as they have no
membrane bound nucleus or membrane bound
cell organelles
They are classified according to three shapes
1.
2.
3.
Spherical (cocci)
Rod (bacillus)
Spiral (spirillum)
Bacterial Shapes
Spherical (cocci)
 E.g. Staphoolococcus
aureus
 Causes pneumonia
Rod (bacillus)
 E.g. Bacillus anthracis
 Cause of anthrax
 Escherichia coli (E.coli)
 Live in human gut
Spirillum (spiral)
 E.g.Treponema
pallidum
 Causes syphilis
Bacterial shapes
11
Bacterial size
A diagram
of a
bacterium
13
Use book page 238 to label….
Bacterial cell - Diagram
15
Cell Parts & Function
Use your book to find the functions
below
Part of cell
Cell wall
Cytoplasm
Loop of DNA (deoxyribonucleic
acid)
Capsule
Flagella
Plasmid
Function
Cell Parts & Function
Part of cell
Function
Cell wall
shape & structure
Prevents bacteria from bursting
Cytoplasm
contains ribosomes and storage
granules but no mitochondria or
chloroplasts
Loop of DNA (deoxyribonucleic
acid)
single strand of DNA
Capsule
protection
Flagella
movement
Plasmid
circular piece of DNA containing
few genes for resistance to
antibiotics
Bacterial Reproduction
http://www.youtube.com/watch?v=DY9DN
WcqxI4&feature=endscreen&NR=1
Bacterial reproduction
•
Bacteria reproduce asexually
•
The method used by a bacteria to reproduce is
called Binary Fission
Bacterial reproduction
 DNA is replicated
 The cell elongates and the two chromosomes
separate
 The cell wall grows to divide the cell in two
 Two identical daughter cells are formed
Bacterial Reproduction
•Asexually - offspring are genetically identical
•New mutations can spread very quickly
•This is how bacteria become resistant to new
antibiotics
Endospore formation
 Some bacteria can withstand unfavourable
conditions (lack of water, heat) by producing
endospores
 http://www.youtube.com/watch?v=NAcowl
iknPs&feature=related
Spore formation
Endospore: Formed during unfavourable
conditions. Contents of cell shrinks and tough
outer coat formed within the cell
24
Endospore formation
These are formed when the bacterial
chromosome replicates
Endospore formation
 One of the new strands becomes enclosed in
an endospore
Endospore
 The parent cell then breaks down and the
endospore remains dormant
Endospore formation
 When conditions are favourable the spores
absorb water, break their walls and reproduce
by binary fission
Complete in your copy
1. Name the three different types of bacteria.
2. By what method do bacteria reproduce.
3. Describe the steps involved in this method
of reproduction
4.
Can you….
Name 3 types of bacterial cell and their structure
2. Explain reproduction of bacteria
1.
Section 2
Aidhm
Explain nutrition of bacteria
2. State the factors affecting growth of micro-organisms
3. Define the term pathogenic
4. Name 2 Beneficial & 2 Harmful bacteria
1.
Bacterial Nutrition
Bacterial Nutrition
E.g. Bacillus anthracis
Autotrophic and Heterotrophic
 Autotrophic – organisms which make their own
food
 Heterotrophic – organisms which take in food
made by other organisms
Factors affecting the growth of
bacteria
Factors affecting the growth of
bacteria
 The correct amount of the
following is needed for growth:
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Temperature
pH
Oxygen concentration
External solute concentration
Pressure
1. Temperature
Bacteria will grow
•
Best between 20°C and 30°C.
•
Some can tolerate much higher temperatures
•
Slowly at low temperatures
2. pH
•
Most bacteria grow at neutral pH. Some can grow at
low pH
3. Oxygen concentration
• Aerobic bacteria: require oxygen for respiration
e.g. Streptococcus
• Anaerobic bacteria: do not require oxygen
1.
2.
Facultative anaerobes: respire with or without
oxygen e.g. E.Coli
Obligate anaerobes: only respire in the
absence of oxygen e.g. Clostridium tetani
4. External Solute concentration
 Bacteria can gain or lose water by osmosis
 If the external solute concentration is
higher water moves out of the bacteria
(Dehydration)
 If the external solute concentration is
lower the water will enter the bacteria
5. Pressure
 The growth of most bacteria is inhibited by
high pressures.
 Some bacteria can withstand high pressures.
(used in bioreactors)
Economic importance of bacteria
Beneficial bacteria
 Milk Cheese/Yoghurt: Bacteria such as
Lactobacillus
 Insulin, enzymes, drugs, food
flavourings: Genetically modified
bacteria e.g. E. Coli
Economic importance of bacteria
Harmful bacteria
 Pathogens: Micro-organisms that cause
disease E.g. Bacillus anthracis causes
anthrax
 Food Spoilage: Bacteria can cause food
spoilage
Learning check
As easy as 1 2 3
Students in groups of 3 and number them 1-3.
3 statements on the board which the corresponding
individual must explain to the rest of the group.
1. Bacteria reproduce asexually
2. Some bacteria make their own food, others don’t.
3. Some factors effect the growth of bacteria
Back to
Plenaries
Can you….
Explain nutrition of bacteria
2. State the factors affecting growth of micro-organisms
3. Define the term pathogenic
4. Name 2 Beneficial & 2 Harmful bacteria
1.
Section 3
Aidhm
Define the term antibiotics
2. State the role of antibiotics
3. Outline the potential abuse of antibiotics
1.
Antibiotics
Vaccine for Virulent Strain of Hospital
Bug
http://www.youtube.com/watch?v=48Bmo
GmWAiU
Antibiotics
 Substances produced by
micro-organisms that
inhibit the growth or
reproduction of
bacteria or fungi
 No effect on viruses.
Role of Antibiotics
 Penicillin: first antibiotic,
isolated from a fungus by
Alexander Fleming
 Now antibiotics are mostly
produced by genetically
engineered bacteria
Antibiotic Resistance
 When an antibiotic is used to treat an infection most
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bacteria are killed
Genetic mutations in bacterial genes can allow
bacteria to develop antibiotic resistance.
‘Sensitive’ bacteria killed
Resistant bacteria survive.
Always finish the full course of antibiotics to kill the
resistant bacteria
Further mutations can lead to complete
resistance.
Over use of antibiotics or not finishing antibiotic
course can lead to highly resistant bacteria.
E.g. MRSA
Misuse
1. Overuse of antibiotics: Leads to increased
growth of antibiotic resistant bacteria
2. Failure to complete a course of
antibiotics: allows the bacteria to survive
and re-grow
http://www.rte.ie/news/2012/0120/belfast.html#v
ideo
Can you….
Define the term antibiotics
2. State the role of antibiotics
3. Outline the potential abuse of antibiotics
1.
5-5-1 Deluxe!
Back to
Plenaries
Now reduce that to 5 key words…
Write 5 sentences summarising today’s
topic…
And finally to one word….
Use shapes and pictures to
deluxe-ify 5-5-1