File - Science at St. Dominics

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Leaving Cert Biology
3.1 Diversity of Organisms
Monera (Bacteria)
Leaving Cert Biology
3.1 Diversity of Organisms
Monera (Bacteria) – higher level
• All monera are prokaryotes (Do not
have membrane -bound organelles
such as nuclei, mitochondria or
chloroplasts)
Leaving Cert Biology
3.1 Diversity of Organisms
Monera (Bacteria)
• Basic structure of a Bacterium:
Leaving Cert Biology
3.1 Diversity of Organisms
Monera (Bacteria)
• three main shapes:
Leaving Cert Biology
3.1 Diversity of Organisms
Tuberculosis
Leaving Cert Biology
3.1 Diversity of Organisms
Leaving Cert Biology
3.1 Diversity of Organisms
Chlamydia
Leaving Cert Biology
3.1 Diversity of Organisms
Leaving Cert Biology
3.1 Diversity of Organisms
Leaving Cert Biology
3.1 Diversity of Organisms
Leaving Cert Biology
3.1 Diversity of Organisms
Do you know..
• What the five kingdoms of living things
are?
• What are prokaryotes?
• Which group are prokaryotes?
• The structure of a bacterium?
• The three different shapes of bacteria?
Leaving Cert Biology
3.1 Diversity of Organisms
Monera (Bacteria)
Nutrition in Bacteria
Autotrophic
Photosynthesis
Chemosynthesis
Heterotrophic
Parasitic
Saprophytic
Autotrophic Bacteria – Make
their own food
Leaving Cert Biology
3.1 Diversity of Organisms
-Photosynthetic bacteria
produce their own food using
light as a source of energy
e.g. Purple sulfur bacteria
- Chemosynthetic bacteria
produce their own food
using energy gained from
breaking down sulfur,
nitrogen and iron
compounds e.g. Nitrifying
bacteria
Leaving Cert Biology
3.1 Diversity of Organisms
Heterotrophic Bacteria - take in food made by other organisms.
- Parasitic bacteria take in food by
feeding on a live host e.g.
salmonella bacteria
- Saprophytic bacteria take in food
by feeding on dead organic matter
e.g. psueudomonas.
Leaving Cert Biology
3.1 Diversity of Organisms
Monera (Bacteria)
Nutrition in Bacteria
Autotrophic
Photosynthesis
Chemosynthesis
Heterotrophic
Parasitic
Saprophytic
Leaving Cert Biology
3.1 Diversity of Organisms
Purple sulfur bacteria
Leaving Cert Biology
3.1 Diversity of Organisms
Nitrifying bacteria
Leaving Cert Biology
3.1 Diversity of Organisms
Salmonella
Leaving Cert Biology
3.1 Diversity of Organisms
Pseudomonas
Leaving Cert Biology
3.1 Diversity of Organisms
Factors affecting the growth of
bacteria
Factor
Temperature
Oxygen
pH
External
solution
concentration
Pressure on
bacterium
Why would this
effect growth?
What conditions would
favour growth usually?
Leaving Cert Biology
3.1 Diversity of Organisms
Factors affecting the growth of bacteria
Temperature – has an important influence on
enzyme action. Most grow at temperatures
between 20 – 40oC BUT there are exceptions!
Leaving Cert Biology
3.1 Diversity of Organisms
Factors affecting the growth of
Bacteria
2. Oxygen concentration – Most bacteria die
without oxygen because they need it to
respire!
Leaving Cert Biology
3.1 Diversity of Organisms
Factors affecting the growth of
Bacteria
3.pH – Has an important influence on enzyme
action. Most bacteria survive in pH of 7-8, but some
can tolerate higher or lower ranges.
4.Pressure – High pressures
because it causes the cell
wall to collapse.
Leaving Cert Biology
3.1 Diversity of Organisms
Factors affecting the growth
of Bacteria
5. External solute concentration–
Bacteria absorb water from their environment by osmosis
so most need to live in solutions with a higher
concentration of water.
Bacteria that live in lower concentration of water may lose
water, become dehydrated and die.
Leaving Cert Biology
3.1 Diversity of Organisms
What you should learn about in
today’s class
• Why bacteria make endospores
• How bacteria reproduce
Leaving Cert Biology
3.1 Diversity of Organisms
Homework
• Pg 229 Q15a,b (not part vi)
• Learn about reproduction in bacteria
Leaving Cert Biology
3.1 Diversity of Organisms
Leaving Cert Biology
3.1 Diversity of Organisms
Bacteria forming endospores
• Endospores are formed in unfavourable conditions:
The cell shrinks, rounds up and forms a thick wall within the
original structure
When conditions are favourable the spores absorb
water, break their walls and reproduce by Binary
fission
Leaving Cert Biology
3.1 Diversity of Organisms
Leaving Cert Biology
3.1 Diversity of Organisms
Leaving Cert Biology
3.1 Diversity of Organisms
Bacterial reproduction
Leaving Cert Biology
3.1 Diversity of Organisms
Think about it..
1. Is it sexual reproduction or asexual
reproduction?
2. Does it happen quickly or slowly?
3. If a change in DNA happens in one
bacteria how would it effect daughter
cells?
Write out the full sentence answers to these
questions under your diagram
Leaving Cert Biology
3.1 Diversity of Organisms
Monera (Bacteria)
• Reproduction is asexual and occurs by Binary fission
1. DNA replicates
2. Cell elongates and pushes the
replicated DNA apart
3. Cell membranes and cell wall
grow inwards
4. Two identical cells are formed.
Leaving Cert Biology
3.1 Diversity of Organisms
Leaving Cert Biology
3.1 Diversity of Organisms
Leaving Cert Biology
3.1 Diversity of Organisms
Mutations in Bacteria
• If there is a mutation (change in genetic
material) it will be passed on very quickly to a
large number of bacteria
Leaving Cert Biology
3.1 Diversity of Organisms
What do you know about?
• What is an endospore? When is it formed?
• Is bacterial reproduction asexual or
sexual?
• What is this type of reproduction called?
• What are the main stages?
• What happens if there is a mutation in a
bacterium?
Leaving Cert Biology
3.1 Diversity of Organisms
Today’s objectives
• To learn what antibiotics are
Leaving Cert Biology
3.1 Diversity of Organisms
Antibiotics
• Some bacteria make antibiotics
Def Antibiotics are chemicals made by microorganisms that
stop the growth or kill microorganims.
Since antibiotics do
not harm humans we
can use them for our
own defence against
pathogenic bacteria!
Leaving Cert Biology
3.1 Diversity of Organisms
Antibiotic resistance
Some bacteria may develop a mutation in a gene and this
may give them a way to fight against the antibiotic
Any bacteria which do
become resistant will
have no competitors and
will reproduce very
quickly!
Leaving Cert Biology
3.1 Diversity of Organisms
Leaving Cert Biology
3.1 Diversity of Organisms
Leaving Cert Biology
3.1 Diversity of Organisms
Antibiotic resistance
Leaving Cert Biology
3.1 Diversity of Organisms
Antibiotics can be abused 
The overuse of antibiotics causes more antibiotic
resistant bacteria to develop
This often happens when antibiotics are available without
prescriptions or when patients do not finish prescriptions
fully!
Leaving Cert Biology
3.1 Diversity of Organisms
Do you know..
•
•
•
•
•
What an endospore is?
How reproduction in bacteria happens?
How antibiotics are made?
Why antibiotics are useful?
How resistance to antibiotics is developed
in bacteria?
Leaving Cert Biology
3.1 Diversity of Organisms
Pathogenic bacteria
Def Microorganisms that cause disease are
Pathogenic
Do you know any pathogenic bacteria?
Leaving Cert Biology
3.1 Diversity of Organisms
Leaving Cert Biology
3.1 Diversity of Organisms
Leaving Cert Biology
3.1 Diversity of Organisms
Negative effects on the Economy
Lactobacillus spoil milk which wastes money!
E. Coli bacteria and Salmonella can cause food poisoning!
(medical care costs!!!)
Leaving Cert Biology
3.1 Diversity of Organisms
Positive effects on the Economy
Lactobacillus - used to make yogurt and
cheese.
E.Coli bacteria are genetically engineered
and used to make insulin etc