HE DIFFERENCES BETWEEN PLANT AND ANIMAL VIRUSES：植物和动物病毒之间的差异.ppt

KINGDOM : FUNGI ABBOTTS COLLEGE,KINGDOM FUNGI,ABBOTTS,TOPICS,Structure Characteristics Diseases,Neither plants nor animals E.g. mushrooms, moulds and yeast Estimated about 1 million species,GENERAL CHARACTERISTICS,Fungi are found everywhere invisible to the naked eye Mostly free-living (live in soil, air and dead organic matter) Are heterotrophs - lack chlorophyll Saprotrophic feed on dead organisms Parasitic get nourishment from a living host and cause diseases as a result,FORM SYMBIOTIC RELATIONSHIPS,Some fungi live in symbiotic relationships with plants and animals The term symbiosis commonly describes close and often long-term interactions between different biological species.,LICHEN,An association of a fungi and algae The fungus supplies the alga with water and minerals The alga makes glucose that is absorbed by the fungus,Lichen thallus (cross-section) X 200. The algal cells are a lighter colour. They are surrounded by and held in place by fungal hyphae.,MYCORRHIZAE,Hyphae of a fungus which associate with the roots of many types of plants Fungus gets food from the plant Plant gets an increased surface area for water absorption,MOST FUNGI ARE USEFUL,They are primary decomposers of dead organic matter Clean the environment Nutrients are re-cycled and returned to the soil,FUNGI: REPRODUCTION,Asexually by means of spores Sexually when conditions are unfavourable by means of zygospores By budding or binary fission (yeast),ASEXUAL REPRODUCTION BY SPORES,Spores are the units of asexual reproduction, because a single spore develops into a new organism. By contrast, gametes are the units of sexual reproduction, as two gametes need to fuse to create a new organism.,Sexual reproduction by zygospores,A large multinucleate spore formed by union of similar gametes, as in algae or fungi.,budding,BINARY FISSION IN YEAST,STRUCTURE OF FUNGI,Most are multicellular eukaryotes Some are unicellular examples (yeast) Cells walls contain chitin and glucan Multicellular fungi consist of fine branched threads called hyphae,HYPHAE,HYPHA,Is a multi branched tubular cell filled with cytoplasm The tube can be continuous (aseptate) or septate (divided into compartments),MYCELIUM,Hyphae branch repeatedly to form a network called the mycelium Which makes up the thallus (vegetative part of the fungus),SPORANGIA,When a fungus reproduces asexually it forms sporangia (spore producing bodies),HARMFUL FUNGI,Pathogenic fungi are parasites causing ill health in plants and animals Get their nourishment from a living host E.g. thrush and athletes foot in man E.g. rust in plants,FUNGAL DISEASES,Thrush Rusts Ringworm Athletes foot,CANDIDIASIS/THRUSH,Also called a candida infection or yeast infection Caused by Candida albicans (a yeast /fungus) Affects the mucous membranes Can occur harmlessly in the body Healthy immune system: friendly bacteria keep them in check in the intestine Under certain conditions they grow too fast and cause an infection Common in the mouth, vagina or GI tract in babies,FACTORS WHICH ENCOURAGE GROWTH,Taking antibiotics reduces the number of friendly bacteria AIDS and cancer weakens the immune system Stress, poor diet, lack of sleep Tight clothing promotes moisture build up in genital areas,MANAGEMENT OF THRUSH,Oral thrush antifungal mouthwash Vaginal yeast infections antifungal medication e.g. creams,ATHLETES FOOT,Caused by a fungus called T