Micro-organisms (microbes)

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. Bacteriahttp://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. 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 • http://www.icbm.de/pmbio/mikrobiologischer-garten/eng/index.php3

40. Microscopic hyphae Sporangia

41. 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?