1. Micro-organisms (microbes)
Very small organisms usually only visible under a microscope

2. Learning objectives Label a generalised bacterial cell
Describe methods of feeding (nutrition), respiration, excretion, and reproduction in bacteria.
Label a generalised virus
Describe the method of replication of viruses in living cells
Label a generalised fungus
Describe methods of feeding (nutrition), respiration, excretion, and reproduction in fungi.
Describe factors that affect the life processes (MRS GREN) of microbes.
Describe how microbes are cultured (grown) in a laboratory.
Describe chemical control of microbes, (antiseptic, antibiotics, disinfectant).
Explain ways in which humans use fungi, bacteria, and viruses (including; nutrient cycles, food production, sewage treatment, composting).
Identify ways in which humans are affected (both helpful and harmful) by bacteria, fungi, and viruses. Including; disease, food poisoning, and antibiotics.
Explain how microbes can become resistant to antibiotics.

3. Fungi

4. Fungi
A group of immobile organisms that feed on dead or living organisms and exposed food
70,000 known kinds
50 fungi among NZ’s most threatened species
Can be unicellular and
multi-cellular
Most common cause of
plant disease

5. Structure Hyphae: Fine feeding threads
Sporagium: Spore capsule that produces spores
Spores: reproductive cell, germinates and spreads out hyphae

6. Mass of Hyphae

7. MRS GREN Movement Respiration Sensitivity Growth Reproduction
Excretion
Nutrition

8. Movement
Immobile
But can spread by producing networks of hyphae.

10. Respiration
Carry out aerobic and anaerobic respiration to create energy from food

11. Sensitivity
Show active responses to their surroundings

12. Growth
Grow by spread of hyphae

13. Reproduction Asexual and sexual production of spores
Spores germinate when they land on tissue and put out hyphae.

14. Excretion
Allow waste to diffuse out of cells and into the surrounding environment

15. Nutrition
Secrete enzymes that break down food, the absorb digested food
Extra-cellular digestion

16. Bacteria http://www.youtube.com/watch?v=tqOVYpkZ0qs

17. Bacteria Bacteria are unicellular organisms with no nucleus
Sphere, rod, or spiral shaped
Usually 0.01mm in length and only visible under the higher powers of the microscope
Over 3000 known kinds
They are found almost everywhere including in living things
Colonies growing on agar look like shiny spots of various colours

18. Spherical (coccus)
Rod shaped
(bacillus)
Spiral (spirillum)

19. Bacteria structure

20. Structure functions Cell wall: Maintains cell shape
Cell membrane: Controls entry and exit of
materials
Chromosome: Carries genetic information
Cytoplasm: fills cell and provides medium for
chemical reactions to occur
Flagellum: Assists the bacterium to move
Capsule: Provides protection from external
environment

21. MRS GREN Movement Respiration Sensitivity Growth Reproduction
Excretion
Nutrition

22. Movement Many bacteria move by hair-like threads called flagella.
These are made up of Wqlong stands of protein
Non-flagellum bacteria float in water or on the wind.
Or are carried/spread by
their hosts

24. Respiration Not breathing!
The process of releasing energy from food molecules
Bacteria carry out:
- Aerobic respiration (requires oxygen)
- Anaerobic respiration (without the presence of oxygen)

25. Sensitivity Bacteria display sensitivity to their environment.
They can move along concentration gradients until they reach their optimum environment.
i.e. Temperature/ acidity/ Oxygen/ Magnetic

26. Growth
In optimum conditions bacteria do grow, but their goal is reproduction so they grow up to a certain point where they have enough resources to reproduce.

27. Reproduction Reproduce asexually by a process called Binary fission
The bacterium’s chromosome is duplicated and the cell then pinches in half and two identical
daughter cells are
produced

29. Excretion
Bacteria excrete by allowing waste to diffuse out of the cell membrane into the environment
i.e. CO2 from aerobic respiration

30. Nutrition
Bacteria ‘feed’ by secreting enzymes which break down their food source into smaller molecules that can be absorbed by the bacteria.
This is called
extra-cellular
digestion.

31. Parasites – Live on or in larger organisms. and feed off them
Parasites – Live on or in larger organisms and feed off them. If they cause disease they are called pathogens.
Saprophytes – Consume dead matter These bacteria are scavengers and decomposers.
Autotrophs – Self-feeders. They can make food from non-living materials i.e. chemicals/ sunlight.
- Green and purple sulfur bacteria.

33. Factors that inhibit bacteria growth
Light
Temperature
Chemicals
Acidity
Food supply

34. Classification
Bacteria fall into a category of life called the Prokaryotes or DNA, is not enclosed in a nucleus.
Bacteria are the only prokaryotes. All other life forms are Eukaryotes creatures whose cells have nuclei.

35. Fungi and Bacteria

40. Microscopic hyphae Sporangia

41. Microbes and Biotechnology
Helpful and harmful:
Microbes and Biotechnology

42. Helpful Fungi
Fungi are used in many processes including the brewing of beer and ginger beer, the making of bread and also the making of wine.
Fungi are also used in the production of medicines such as the antibiotic penicillin.
Mushrooms and Truffles are fungi that we eat.

43. Fungi - yeast Saccharomyces cerevisiae baker's yeast.
Converts sugar into Carbon dioxide by anaerobic respiration causing the bread to rise

44. Antibiotics
Fungi produce compounds to kill bacteria that might compete for their food source.
We call this substance antibiotics.
Penicillin is an example of this.

45. Helpful Bacteria Many bacteria are helpful in….
Compost, nitrogen fixing bacteria in plants
Cellulose digesting bacteria in the gut of herbivores.
We use yoghurt bacteria to convert the sugar in milk to lactic acid which makes yoghurt.

46. Escherichia coli One of many kinds of microbes that live in your gut.
Helps you digest your food every day.

47. Lactobacillus acidophilus
Lactobacillus acidophilus is the bacteria that turns milk into yogurt.

48. Bacteria and Medicine:
Bacteria can be genetically engineered to produce medical drugs.
e.g. insulin

49. Making Yogurt!!
Heat 200mls of milk in a beaker until it reaches ~ 40oC (close to body temperature)
Take of heat and add 1 tablespoon of yogurt and stir to mix.
Seal in air tight container, and incubate.
In a test tube, test the pH of 2mL of milk. Add some sulfuric acid until the caesin precipitates. Re-test pH

50. Questions Why did we incubate our cultures at 28oC?
Why were the plates incubated upside down?
What must be present in the natural yoghurt for this to work?
Why was the milk heated first?
Why does powder yoghurt last longer than yoghurt pots?

51. Bacteria and nutrient cycles

52. Nitrogen cycle
Plants and animals need nitrogen to make protein but they can’t use the nitrogen in the air because they cannot break open the N2 molecules.
Nitrogen fixing bacteria in the roots of plants like clover, convert nitrogen gas from the air into nitrates which can be used by plants as a source of nitrogen

53. Saprophyte +

54. Nitrogen cycle
Animals get there nitrogen by eating plants or animal protein.
Dead animal and plant protein, and animal urine is broken down by decomposers. The nitrogen changes back to nitrates.
Some bacteria in the soil can change nitrates back into nitrogen gas, these are denitrifying bacteria.

55. Nitrogen Cycle

56. Ginger Beer
Ginger beer is a non-alcoholic soft drink made by adding ginger, sugar, water, and the fungus yeast together in a sterile container. The container is then kept in a warm place for a few days. At the end of this time, the container is heated at high temperature before the ginger beer is bottled.
(a) Name the conditions required to obtain maximum growth of the yeast fungus.
(b) Explain why the container of ginger beer is heated to a high temperature before its contents are bottled.
The yeast undergoes anaerobic respiration in the container.
(c) What does anaerobic mean?
(d) Name TWO products of this reaction.

57. Nitrogen fixing bacteria
Atmosphere
Nitrogen fixing bacteria
Denitrifying bacteria
Decomposers
Dead matter waste

58. Naturally helpful: Helpful and harmful:
Many bacteria and fungi are decomposers breaking down dead tissue (e.g. in compost heaps).
These micro-organisms release nutrients that plants can absorb. They form important parts of the nitrogen and carbon cycle.

59. Carbon cycle
Carbon is released from dead matter by decomposers into the atmosphere as carbon dioxide gas, which is absorbed by plants as they manufacture food.

61. Brainpop
Carbon cycle

62. Extra cellular digestion
Cell membrane
Pathogen
Anaerobic
Enzyme
Decomposers
Binary fission
Extra cellular digestion
Spores
Respiration
Saprophyte

63. Chemical control of microbes

64. Disinfectants
Disinfectants are antimicrobial agents that are applied to non-living objects to destroy microorganisms,
Kill microbes but may harm living tissue
Bactericide

65. Examples of disinfectant
Alcohols
Janola
Harpic
Dettol

66. Antiseptics
Antiseptics are antimicrobial substances that are applied to living tissue/skin to prevent infection.
Inhibit growth of microbes and do not harm living tissue.
Used for sensitive areas such as mouth, open wounds, and are often diluted disinfectants
Bacteriostatic or bacteriocide

67. Examples of antiseptics
Iodine
Soaps
Listerine mouth wash

68. Antibiotics
An antibiotic is a chemical compound that inhibits the growth of bacteria in the body
Target specific – only affects bacterial cells so has little or no side effects.
Can be produced by fungi e.g. penicillin

70. Aerobic and anaerobic

71. Name this process Bacteria and food particle Enzymes secreted outside
Food enters the bacteria
Enzymes digest food particle

72. Name this process A single bacterium just before
reproduction
The DNA replicates and divides
Cell membrane pinches together
Two bacteria are formed

73. In ideal conditions they can reproduce every 20 minutes.
This rapid increase in numbers is called exponential growth.
1.0
Growth of bacteria with time.
0.5
Number of bacteria (millions)
Time since infection (minutes)
100
200
300
400

74. Limits to growth
They will not increase forever as eventually a lack of food or space or the build up of toxins in the form of waste products will cause the numbers to level off and then decrease.

75. Maximum number of bacteria
Decreasing numbers
Number of bacteria (millions)
Rapid growth in number
Slow growth in number
Time since infection (minutes)

76. Controlling microbes

77. Tangrams
In groups complete a tangram by matching definitions to terms.
Once finished answer below:
Describe three differences between fungi and bacteria
How do we know bacteria and fungi are living?
What is a saphrophyte?

78. Home learning
Pages so far:
Pages for tonight:
DUE MONDAY!!!!!!!!!!!!

79. Aerobic and Anaerobic respiration
Produces:
Aerobic =
Respiration is the break down of food to produce energy needed for living.

80. Viruses Viruses are simple but effective pathogens
Viruses can infect all living things
Range from 20 to 20millionth of a millimetre.
Can only be seen with an electron microscope.

81. Viral structure Viruses can in a variety of shapes
Consists of a core of genetic material surrounded by a protein coat=capsid
Some viruses also have a membrane. This membrane can have proteins embedded in it

82. Viruses

84. Viral reproduction
Essentially all a virus is a set of instructions for making new viruses.
MRS GREN is not followed by viruses and the only ‘living’ characteristic that they have is reproduction
They lie on the border between the living and no living worlds

85. Viral reproduction Cannot reproduce independently.
When a virus lands on the surface of a cell it inserts its genes into the host cell.
The viral genes take over the cells processes to produce new viruses.
These build up in the cell until it eventually bursts releasing the new viruses into the host where they can infect new cells.

86. Viruses are pathogens as the host cell is always damaged by the virus.
Human viral diseases include:
Colds
Flu
Aids

87. Viruses and pest control
Some viruses can be intentionally released to control pest
e.g. calcivirus and rabbits

88. Harmful to whom, that is the question?
Harmful Microbes
Harmful to whom, that is the question?

89. Harmful Microbes A few types of micro-organisms cause disease.
They are called pathogens.
An infectious disease is one that can be passed on from person to person and this can happen in a variety of different ways.

90. Some of the ways to get sick
Contact with body fluids
(e.g. blood, semen, saliva
Contact with infected materials like
Towels and handkerchiefs
Catching a disease
Skin contact
Through the air
Contaminated food or water
Just because you are exposed to these daily
does not mean you will get sick!!

91. Pathogenic micro-organisms
When a pathogen grows in your body an infection occurs.
The pathogen may damage tissue or produce toxins that poison cells.

93. 1. Barrier and chemical warfare
The skin is a water- tight barrier which helps to keep pathogens out.
If they enter the body openings, then an enzyme called lysozyme in the tears, mucous, saliva, and urine kills microbes. Stomach acid kills most of the bacteria in food.

94. In the blood
If pathogens make it through the skin, then phagocytes, which are patrolling white blood cells, attack and engulf them.

95. This is a macrophage and a lymphocyte, found in your blood that wards off infection. It is homing in on a chain of nasty Streptococcus bacteria.

96. Lymphocytes
On the outer surface of the pathogen are unique markers called antigens, which escape into the blood.
White blood cells called lymphocytes absorb the antigens and release antibodies into the blood stream.
The antibody recognises the pathogen that made the antigen and destroys it.
As different pathogens make different antigens, there are many antibodies floating around in blood.

97. Immunity to Disease
When you are first infected by a pathogen, they multiply rapidly causing symptoms of the disease.
As antibody levels build up, the pathogens are killed.
You then have an immunity to further infection by that pathogen, because you have antibodies in your blood that will recognise the antigens released by that specific pathogen.

98. Vaccinations
You can gain artificial immunity to disease, by being injected with weakened or dead pathogens, which stimulate the lymphocytes to produce antibodies against them.
If you then get infected by the living pathogen, you already have the antibodies which can deal with them. This is called a vaccination.
Antibiotics are chemicals produced by fungi which are effective at killing bacteria. When taken, they kill pathogens without affecting the cells of the host.
Bacteria develop resistance to a particular antibiotic through genetic changes known as mutations. They then multiply passing on the resistant gene to their offspring.

101. Antibiotic resistance
Variation exists in all bacterial populations
Some bacteria possess a resistance to antibiotics
In the presence of antibiotics these bacteria have an advantage and can survive longer
Improper use of antibiotics can lead to these bacteria building up in the population leading to antibiotic resistance

103. TB
Tuberculosis is a common and deadly disease that generally affects the lungs
Treatment of active TB requires taking a mixture of antibiotics for 6-12months
Antibiotic resistant TB is an issue in less developed countries due to the cost and accessibility of the drugs
As resistance increases more expensive drugs are required for longer periods of time.

106. Fighting viruses
When we are infected with a virus our immune system detects the invaders and produces antibodies.
Antibodies are proteins produced by white blood cells that help destroy pathogens inside the body
Antibodies recognise antigens (markers on pathogens)
The body holds a memory of the virus

107. Virus protein coats
Viruses have a unique ability for escaping our immune system
They can change/mutate their protein coats allowing them to go undetected by our memory cells causing us to show the symptoms of the illness
This produces different strains of viruses and is the reason behind why we can have more than one flu or cold a year.