VIRUSES, BACTERIA, PROTISTS AND FUNGI

1. VIRUSES, BACTERIA, PROTISTS AND FUNGI MODULE 2: LIFE AT MOLECULAR, CELLULAR AND TISSUE LEVEL

2. MICROBES/MICRO ORGANISMS • Some organisms are so small, that it can’t be seen with the naked eye • This group includes: • VIRUSES: Smaller than a cell and does not form part of the 5 Kingdom system that classifies living organisms • BACTERIA: unicellular procariotic organisms • PROTISTS: unicellular protosoa with animal-like characteristics as well as algae with plant-like characteristics • FUNGI: includes mushrooms, unicellular yeast cells and fungi that consist of thread-like filaments

4. A Disease causing organism

6. They contain either DNA or RNA but never both. • They are OBLIGATE INTRA-CELLULAR PARASITES – can only replicate within a living host cell • Virusses are host or tissue specific • They are PATHOGENS (disease causing organisms) • Virusses REPRODUCE by changing the genetic material of the host cell to its own

7. They can’t feed • They can’t respire • They can’t reproduce, only multiply • They can’t excrete • They show no form of locomotion • They show no sensitivity • They can’t grow

8. They have no nucleus • They have no cytoplasm • They have no organelles

9. Some viruses that attack bavteria are more complex in structure: • Spherical head • Rod-shaped • Known as a BACTERIOPHAGE

10. REPRODUCTION OF VIRUSES • The virus approaches a cell • Virus attaches to receptor on cell membrane of host cell • Virus engulfed by endocytosis • Virus wall disintegrates • Virus releases its nucleic acid • A new virus nucleic acid is formed from nucleic acid of host cell • New virus with protein shield is formed • Host cell burts open and new viruses are released • Host cell destroyed in the process

11. 6. New viruses are released as host cells burst open and is destroyed 1. Virus approaches the host cell 5. New protein shields (capsids) are formed around nucleic acids 4. Virus uses the host cell’s nucleic acid to replicate its own 2. The virus attaches itself to the host cell 3. The virus releases its nucleic acid

12. GENERAL CHARACTERISTICS: • Unicellular and simple organisms • Contain no true nucleus – thus PROKARYOTIC • Some are AUTOTROPHIC (produce own food by means of photosynthesis and chemosynthesis) • Most are HETEROTROPHIC and can’s produce their own food. • Heterotrophic bacteria are either parasitic or saprophytes or live mutualistic with other organisms

14. REPRODUCTION IN BACTERIA • ASEXUALLY through BINARY FISSION: • Single cell divide in TWO cells with identical DNA composition • As soon as conditions become UNFAVOURABLE, some bacteria form ENDOSPORES that can withstand extreme temperatures and drought. • Develop a hard outer shell/wall and as soon as conditions become favourable again, the endospore burst open and become active again

15. PATHOGEN – an organism that causes disease • Some bacteria cause disease and are pathogenic • Cause diseases such as cholera, tuberculosis and anthrax (p.96 Focus on Life Sciences)

16. Decompose dead plant and animal matter – decompose sewage at purification plants • Play role in nitrogen cycle • Economic uses: production of yoghurt, cheese, vinegar, gherkins, etc. • Production of Pharmaceutical substances such asantibiotics (together with moulds) vaccines and steroids • Used in biotechnology, such as the production of human insulin

17. KINGDOM: PROTISTA • The kingdom with the LARGEST DIVERSITY ( more than 200 000 species) • PROTOZOA – animal-like, unicellular heterotrophic organisms • ALGAE – plant-like, autotrophic organisms • FUNGUS-SLIME + WATER SLIME – fungus-like organisms

18. GENERAL CHARACTERISTICS:PROTISTS • Some are unicellular and microscopic small; others are multicellular and can be seen with the naked eye • Eukaryotic: contain a true nucleus • Algae are autotrophic; and others are heterotrophic • Reproduction mainly asexually by binary fission; some algae reproduce sexually • Occur everywhere where there is water • Some are PATHOGENIC and cause disease e.g. Malaria and Sleeping sickness

19. STRUCTURE OF PROTISTS • E.g. The Amoeba proteus

20. Unicellular with irregular shape (shape changes as it moves or take food in) • Body consists of cytoplasm and nucleus • Cytoplasm consists of: • (i) ectoplasm: clear, jelly-like section on the outside • (ii) endoplasm: grey, liquid part on the inside • Outer membrane is plasma membrane

21. Food vacuole: in which food is digested • Contractile vacuole: responsible for osmoregulation (control water balance) • Nucleus: control all cell activities • Pseudopodia (false feet): ectoplasm forms protrusions anywhere and is temporary

23. Yeasts are unicellular; mushrooms and moulds are multicellular • Eukaryotes: contain true nucleus • Contain no chlorophyl and are HETEROTROPHIC • Most fungi are SAPROPHYTES (live on dead, organic matter) • Sommige is PARASIETE – teer op lewendemateriaal • Sommige is MUTUALISTIES- leef SAAM met anderorganismes

24. More characteristics…. • Most fungi are USEFULL e.g. • (i) decompose dead organic matter (together with bacteria) • (ii) are used in production of antibiotic • (iii) yeasts are used for baking of bread and production of alcoholic drinks

25. Other fungi are PATHOGENIC… • cause diseases such as: • Rust in Corn • Athlete’s foot • Thrush in humans

27. Rhizopusis multicellular and consists of branched filaments, the hyphae • The hyphae are interwoven to form the vegetative body, the mycelium • Rhizopusis aTHALLUS – no true roots, stems and leaves are distinguished.

28. 3 TYPES hyphae: • (a) STOLONS: the hyphae that branch over the surface of the substrate • (b) RHIZOIDS: the hyphae that penetrate the substrate (bread) and anchor the mycelium SPORANGIOPHORE: the hyphae that grow up straight and that carry the sporangia

29. The hyphae are branched • Hyphae contain NO cross walls – in other words, they are ASEPTATE • A large amount of nuclei occur in cytoplasm • NB: Many other fungi’s hyphae contain cross walls (septate)

30. Source of food, e.g. mushrooms • Yeast cells responsible for fermentation process in the production of alcoholic drinks (e.g. Wine and beer), yoghurt and the baking of bread • Certain fungi play role in production of cheese • Is used in production of antibiotic e.g. Penicillin obtained from the mould Penicilliumnotatum

31. Refers to knowledge obtained from communities or cultures over generations through their interactions with their environment • Indigenous knowledge forms the basis for decisions in agriculture, health care, food preparation, education and management of resources • BIOTECHNOLOGY is the use of living organisms in industrial processes (food processing, production of antibiotic and genetic manipulation of agricultural crops

32. Include ancient ways in which living organisms (micro-organisms) were usedto make new products or to adapt existing products. • In South Africa, many indigenous black populations use their knowledge of fermentation for the production of beer, amasienmahewu(mageu)

33. Ask around…. • Ask your Mum, Granny, Grandpa or any other person for a recipe to make ginger beer or pineapple beer. Write it down and paste it in your workbook. • Did you know? Traditional beer made from maize meal/sorghum contain only 3% alcohol as a result of the fermentation process. • Fermentation: where bacteria, yeast or moulds respire in the absence of oxygen and where alcohol and carbon dioxide are formed

34. PRODUCTION OF CHEESE • Lactic acid bacteria is added to pasteurised milk and fermentation takes place • Milk sugar (lactose) is converted into lactic acid • The pH is lowered and the protein in milk (casein) from clots (coagulate) • The enzyme (rennin) are added to form more clots • Solid clots are called curds and the liquid part is called whey • The curd is separated from the whey and allowed to age to form cheese

35. The sugar in grape juice is fermentated by yeast cells occurring on the surface of grapes • The sugar is converted into alcohol and carbon dioxide • Additionacan be added to accelerate the fermentation process • The fermented pulp is known as must • The must is filtered to remove all seeds and skin and placed in large vats/barrels to age

36. Flour, water, yeast and little sugar are combined to form a dough • The carbon dioxide that is released, makes the dough rise • In case the dough is placed in a warm place, the process takes place faster • The alcohol that is formed, evaporates during the baking process

37. Microbes can cause disease The diseases and their severity caused by microbes depend on the type of microbe. Some of these are listed below. VIRUSES BACTERIA FUNGI Influenza (flu) Food poisoning fungal sinusitis Mumps Sore throats Athletes foot Chickenpox Tuberculosis (TB) Onychomycosis Causes discoloured toe nails Candidiasis / Thrush Smallpox Tetanus Polio Cholera Rabies Typhoid German measles Whooping cough Viral meningitis Bacterial meningitis

38. Research the following on AIDS: • Causes of AIDS • How AIDS is transmitted • Effect of AIDS on the human body • Effect on children and familiesct on the economy of South Africa

39. Management of AIDS under the following: • Testing • Treatment • Prevention • ETHICS, BELIEFS AND ATTITUDES REGARDING HIV/AIDS

40. BACTERIAL DISEASE • Caused by bacteria Myobacterium tuberculosis • Affect mainly the lungs, but also any other organ in the body • SA is one of 22 countries with highest growth rate in TB infections • TB is a poverty related disease (people stay together in dark rooms with no/poor ventilation)

41. Eyes Oë Ears/Ore Mouth Mond Nose/Neus Skin/Vel Cuts/Oopwonde 18 years and above Genitals Geslags-organe

42. Transmission by air A cough or a sneeze can release millions of microbes into the air which could then infect somebody else. • Transmission in water Dirty water can transmit many diseases, for example, cholera which can be transmitted by drinking the water. How do microbes spread? The spreading of microbes and disease is known as Transmission.

43. Transmission by animals An animal, e.g. a mosquito (which spreads the MALARIA PARASITE) can carry the microbe from one place to another. • Transmission by contact • Many microbes can be exchanged from one person to another by direct or indirect contact: • Direct contact by hand. • Indirect contact by walking on a wet floor already contaminated by someone else who has Athlete’s foot. • Sexual contact.

44. Transmission via Breastfeeding A child can also pick up microbes from the mother, via the milk, if the child is being breastfed. • Transmission by contact There are other forms of indirect contact, the transmission of microbes from mother to unborn child. Transmission through the Placenta If the mother develops the HIV/aids infection, it can be passed on to the unborn child through the placenta.

45. Chemicals called antibiotics can be used to treat bacterial infections. People can be immunised against some diseases by the injection of a vaccine. How do we stop microbes spreading disease We can prevent the spread of disease by making sure that good hygiene is used in key places such as bathrooms and kitchens.

46. The distinction between TB Infection and TB Disease

47. Fighting disease

48. Fighting disease

49. Droplet Nuclei

50. The fate of droplets ….