1. Monera
Bacteria

2. Learning Objectives Name 3 types of bacterial cell
Explain reproduction of bacteria
Explain nutrition of bacteria
State the factors affecting growth of micro-organisms
Define the term pathogenic
Define the term antibiotics
State the role of antibiotics
Outline the potential abuse of antibiotics
Name 2 Beneficial & 2 Harmful bacteria

3. Bacteria
Bacteria are the oldest living organisms on earth They are Prokaryotic – they have no true nucleus, mitochondia or chloroplasts.

4. Habitat Bacteria are found in every possible habitat
Soil, Air, Fresh water, Sea water, Skin, Intestines etc.
Some bacteria can withstand extreme conditions e.g. temperatures of 80 degrees C in hot springs or extreme cold and high pressure on the sea bed.

5. Bacteria in pond water

6. Bacteria on apple

7. Bacteria
Bacteria belong to the kingdom Monera. They are unicellular organisms
They are classified according to three shapes
Spherical (cocci)
Rod (bacillus)
Spiral (spirillum)

8. Bacterial Shapes

9. Spherical (cocci)
E.g. Staphoolococcus aureus
Causes pneumonia

10. Rod (bacillus) E.g. Bacillus anthracis Cause of anthrax
Escherichia coli (E.coli)
Live in human gut

11. Spirillum (spiral)
E.g.Treponema pallidum
Causes syphilis

12. Bacterial size

13. Bacterial Structure

14. Bacterial Structure Cell wall flagella cytoplasm plasmid Cell membrane
Strand of DNA
capsule

15. Functions of Parts of Bacterial Cell
Flagellum
Capsule (slime layer)
Cell Wall
Plasmid (DNA)
Cytoplasm
Storage granules
Chromosome

16. Cell Parts & Function Cell wall - shape & structure
Cytoplasm - contains ribosomes and storage granules but no mitochondria or chloroplasts
Nuclear material -single chromosome of DNA
Capsule* - protection
Flagella* - movement
Plasmid* -circular piece of DNA containing few genes for drug resistance
* Sometimes present.
*Sometimes present

17. Cell wall: made of protein and polysaccharide, rigid and permeable
Cell membrane: selectively permeable.
Cytoplasm: contains a large number of ribosomes.
Nuclear material = DNA (1 circular chromosome and  1 plasmid - small loops of DNA . Plasmids contain genes that are responsible for bacterial resistance to antibiotics.
No organelles (except ribosomes) i.e. no nucleus, mitochondria, chloroplast.
 Flagella: movement
 Capsule: slimy protective coat, in parasitic species for protection. Helps cell to attach to different surfaces.
 chlorophyll
 mesosomes: infoldings in cell membrane which carry out respiration and help during cell division.
 pili: hair-like projections which allow the bacterium to attach to other cells.

19. Quiz – Variety of Organisms
Write down each question and answer:
Name the five kingdoms used to classify organisms?
Define the word species?
Which kingdom has organisms that are prokaryotic?
Amoeba and algae are members of which kingdom?

20. Revision – Bacterial Cell

21. Label the bacterial Cell

22. Useful websites for bacteria

23. Objectives for today’s class Textbook pg 220
Quiz on Classification of organisms
Homework pg. 228
Asexual reproduction in bacteria
Mutations in Bacteria
Antibiotics
Bacterial Endospores
Nutrition in Bacteria
Conditions necessary for growth

24. Bacterial Reproduction

25. Bacterial reproduction
Bacteria reproduce asexually
The method used by a bacteria to reproduce is called Binary Fission

26. Binary Fission
The chromosome attaches to the plasma membrane and the DNA is replicated
Cell wall
Cytoplasm
Plasma membrane
Chromosome

27. The cell elongates and the two chromosomes separate
Binary Fission
The cell elongates and the two chromosomes separate

28. The cell wall grows to divide the cell in two
Binary Fission
The cell wall grows to divide the cell in two

29. Two identical daughter cells are formed
Binary Fission
Two identical daughter cells are formed

31. Bacterial Reproduction
Bacteria reproduce asexually - their offspring are genetically identical
Bacteria has a very short lifecycle (some can reproduce every 20 minutes).
A single bacterium could reproduce over a million bacteria in 7 hours.

33. Mutations in Bacteria
Bacteria reproduce asexually so their offspring are genetically identical. Bacteria can evolve very fast due to the speed at which new mutations can spread within the rapidly growing bacteria. The short life cycle of bacteria mean mutations (changes) can be passed on very quickly so bacteria become resistant to antibiotics very fast.

34. Antibiotics
Antibiotics are chemicals produced by micro-organisms which stop the growth of or kill other micro-organisms without damaging human tissue. Most famous antibiotic is Penicillin

35. Antibiotics
The first antibiotic Penicillin isolated from a fungus by Sir Alexander Fleming
Now antibiotics are mostly produced by genetically engineered bacteria

36. Alexander fleming “the wonder drug” youtube
Antibiotics
Penicillin Fungus
The first antibiotic, penicillin, was discovered in 1929 by Sir Alexander Fleming, who observed inhibition of staphylococci on an agar plate contaminated by a Penicillium mould.
Alexander fleming “the wonder drug” youtube

37. Antibiotics
Antibiotics can be used to control bacterial and fungal infections but do not effect viruses

38. Antibiotics
When an antibiotic is used to treat an infection most of the bacteria are killed
Mutations in bacterial genes can allow bacteria to develop antibiotic resistance.
Antibiotics will then kill ‘sensitive’ bacteria and favour resistant bacteria.
Bacterial strains have emerged which are resistant to almost all known antibiotics (multi-resistant). As a result present day antibiotics become ineffective. MRSA is one example.

39. Misuse Over use of antibiotics
This results in the increased growth of antibiotic resistant bacteria
Failure of some patients to complete a course of antibiotics prescribed to them by a doctor allows the bacteria to survive and re-grow

40. Endospore formation
Some bacteria can withstand unfavourable conditions by producing endospores.
These are resistant cells which enable the bacteria to survive.

41. Endospores Endospores are very difficult to kill.
They can survive a lack of food, water, high temperatures and most poisons.
They are normally not even killed by boiling water.
Some endospores can survive for hundreds of years.

42. A white blood cell injests a disease causing bacteria

43. These are formed when the bacterial chromosome replicates
Endospore formation
These are formed when the bacterial chromosome replicates

44. The parent cell then breaks down and the endospore remains dormant
Endospore formation
The parent cell then breaks down and the endospore remains dormant

45. Endospore formation
One of the new strands becomes enclosed in a tough-walled capsule called an endospore
The parent cell then breaks down and the endospore remains dormant
Endospore

46. Endospore formation
When good conditions return the endospores absorb water, break their walls and reproduce by binary fission

47. Bacterial Nutrition

48. Nutrition
Nutrition is the way in which an organism gets it food. Food supplies the energy and chemicals needed for survival and growth.

49. Nutrition in Bacteria
Bacteria get their food by two main methods:

50. Autotrophic and Heterotrophic
Autotrophic – organisms which make their own food
Heterotrophic – organisms which take in food made by other organisms

51. Autotrophic Bacteria 1. Photosynthetic bacteria
Use light energy to make food
E.g. purple sulphur bacteria

52. Autotrophic Bacteria 2. Chemosynthetic bacteria
Use energy from chemical reactions to make food
E.g. Nitrifying bacteria that convert ammonia to nitrates in the nitrogen cycle

53. Heterotrophic Bacteria
1. Saprophytic Bacteria
Live off dead organic matter
E.g. bacteria of decay in the soil

54. Heterotrophic Bacteria
2. Parasitic Bacteria
Take food from live host
Some cause diseases
E.g. Bacillus anthracis
causes anthrax

55. Heterotrophic Bacteria
3. Saprophytic Bacteria (decomposers) These are bacteria that live on dead organic matter e.g. dead leaves. Some saprophytic bacteria can be used to clean up oil spills.

56. Bacterial Nutrition

57. Learning check Name the three different types of bacteria?
By what method do bacteria reproduce?
Describe the steps involved in this method of reproduction?

58. Quiz 1. How do bacteria develop resistance to antibiotics?
2. Name the 2 main categories of bacteria with regard to their nutritional methods?

59. Factors affecting the growth of bacteria
The growth of bacteria is affected by 5 factors:
Temperature
Oxygen concentration pH
External solute concentration
5. Pressure

60. Factors affecting the growth of bacteria
Too much or too little of any of the factors will slow down the growth of bacteria.
Factors that slow down a process when they are in short supply are called limiting factors.

61. 1. Temperature
The rate of bacterial growth is affected by temperature. Most bacteria grow well between 20°C and 30°C.
Some can tolerate much higher temperatures without their enzymes becoming denatured.
Low temperatures slow down the rate of reaction of enzymes resulting in slower growth.

62. 2. pH Bacterial enzymes are designed to work at a specific pH.
If a bacterium is placed in an unsuitable pH its enzymes will become denatured.
Some bacteria can tolerate very low (acidic) (e.g. Helicobacter bacteria in about 50% of Irish population stomachs) pH and some can tolerate very high (alkaline) pH.

63. Oxygen concentration
Aerobic bacteria require oxygen for respiration e.g. Streptococcus
This is why oxygen is sometimes bubbled through bioreactors

64. New Vocabulary
1. Aerobic Bacteria: require oxygen for respiration 2. Anaerobic Bacteria: do not require oxygen for respiration e.g. Clostridium bacteria 3. Faculative Anaerobes: Can respire with or with out oxygen. E.g. E. Coli in human intestine 4. Obligate Anaerobes: Can only respire in the absence of oxygen e.g. Clostridium tetani

65. External Solute concentration
Bacteria can gain or lose water by osmosis
If the external solute concentration is
higher than the bacterial cytoplasm water will move out of the bacteria (Dehydration)
Food preservation techniques are based on this

66. External Solute concentration
Bacteria can gain or lose water by osmosis
If the external solute concentration is
lower than the bacterial cytoplasm solute concentration water will enter the bacteria
Cell wall will prevent bursting in most cases

67. Pressure 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.

68. Phases in Bacterial Growth
Lag Phase
Bacteria adapt to their environment and make chemicals to prepare for growth.
B Log Phase
Bacteria divide as fast as possible. Growth is exponential due to ideal conditions.
C Stationary Phase
The number of bacteria dying is the same as the number growing.
D Decline Phase
Most of the bacteria start to die.
E Death or Survival Phase
A few survive as Endospores.

69. Growth Curve of Bacteria

70. Economic importance of bacteria
Beneficial bacteria
Lactobacillus are used to convert milk to products such as cheese and yoghurt
Genetically modified bacteria e.g. E. Coli are used to make products e.g. insulin, enzymes, drugs, food flavourings

71. Economic importance of bacteria
Harmful bacteria
E.g. Bacillus anthracis causes anthrax in humans
Other bacterial cause diseases include tuberculosis, typhoid, cholera, diphtheria and brucellosis

72. Beneficial and harmful bacteria
Lactobacillus converts milk to yoghurt and cheese
Antibiotics can be formed by some microorganisms
Bacteria in the colon help produce vitamins
G.M.O.’s are used to make insulin and other useful compounds
Bacteria are active in the Carbon and Nitrogen Cycles
HARMFUL
Pathogenic Bacteria can cause diseases in humans and animals.
Pathogenic Bacteria can cause diseases in plants.
Bacteria can cause food spoilage
Bacteria can cause tooth decay.

73. Bio-reactors Bioreactors Bacteria can be grown in Bioreactors.
These are vessels to which food and oxygen are added.
The bacteria have to be kept at a certain
temperature and pressure.
The bacteria also produce wastes that
must be removed so that they don't get contaminated.
The bacteria are grown to make
antibiotics, food colouring, perfumes, etc.

75. Depth of treatment
Bacterial cells: basic structure (including plasmid DNA), three main types. Reproduction. Nutrition.
Factors affecting growth
Understanding of the term “pathogenic”
Definition and role of “antibiotics”

76. Pathogen A pathogen is a micro-organism that causes disease.
Pathogens include bacteria and some fungi.
e.g. TB and food poisoning

77. Lab procedures when growing micro-organisms
Micro-organism (bacteria, fungi & viruses) can only be seen with an electron microscope.
Colonies (groups) of bacteria and fungi may be grown in the lab on agar plates

78. Lab Procedures
Agar is a substance that contains all the nutrients and minerals bacteria and fungi need to grow.
Agar plates and Agar are sterilised before use.

79. Sterile
A place or substance is sterile if all micro-organisms have been removed. Sterilisation can be down by heating a substance to 120 C for 20 minutes using a special oven called an autoclave

80. Asepsis
Asepsis uses techniques to remove disease causing (pathogenic) micro-organisms and reduce their spread e.g. washing hands, wearing sterile gloves etc.

81. Safety Rules when working with micro-organisms
Many rules including:
Handle all micro-organisms carefully and treat them as if they could cause infection.
Seal all petri-dishes with parafilm to prevent micro-organisms escaping.
Sterilise all containers by heating them to 120 C for 20 minutes.

82. Contemporary issues and technology
Economic importance of bacteria: examples of any two beneficial and any two harmful bacteria.
Potential abuse of antibiotics in medicine.

83. Food Processing
Bacteria are used in large, stainless steel vats (bioreactors) to produce a large range of foods and other products.
Two methods used:
Batch food processing
Continuous flow food processing

84. The methods differ in that each method favours different phases of the bacterial growth curve.
Batch Flow
In batch flow the bacteria are grown until the stationary phase.
After this the bacteria are stopped and removed.
The Bacteria are stored then till more product is needed.
This is the better system and costs less money.
Many antibiotics are made this way.

85. Continuous Flow Processing
In continuous flow the bacteria are kept growing in the Log Phase.
The dead bacteria and wastes are removed constantly to save the live bacteria.
The Bacteria are kept growing to produce constant product (e.gin. sulin).
This system needs constant monitoring and costs more money.
Single Cell Proteins (Quorn/TVP) are made this way.

86. Food Processing
Modern bioprocessing uses bacteria and fungi to make food products.
These include cheese, yoghurt, sweetners, amino acids, vitamins. flavourings,
flavour enhancers, beer and wines.
Humans usually get protein from meat but other sources are now available.
These Single Cell Proteins may be better for the environment and for our health

87. Not just humans take antibiotics
Antibiotics given to animals can be passed on in meat.
This means that the animals help make resistant bacteria
that we may then eat and have inside us.
This could lead to a huge pandemic that could kill millions