- Slides: 28
Don’t worry, You’ll Like Him, he’s a FUNGI! Kingdom Fungi differs in form, size and color u Most grow best in moist, warm environments between 20 -30°C u Most are multicellular (except yeasts) u Major Ecological Roles: 1. Heterotrophic, Decomposers that recycle nutrients in the ecosystem. 2. Symbionts: with plants to help with nutrient absorption, with algae to form lichen, with herbivore insects. 3. Or Parasitic &/or pathogenic. 4. Some can be beneficial u http: //www. nature grid. org. uk/biodive rsity/crypfungi. htm l
Structure of a Fungi Body type: Multicellular u Cell Structure: Cells have cell walls of chitin u Hyphae – threadlike filaments which develop from fungal spores u Hyphae elongate at their tips and branch extensively to form a network of filaments underground called a mycelium. u Mycelium – (many types) some anchor the fungus, others invade the food source, or function as a reproductive structure u
Basic Mushroom Structure
Plants versus Fungi Like plants, many grow anchored in the soil and have cell walls. u Unlike plants, which have cell walls made of cellulose, fungi use a complex carbohydrate called chitin. u Chitin gives the fungal cell walls both strength and flexibility. u Unlike plants, they cannot make their own energy and must absorb it from the surroundings. u
Fungal Reproduction u u One important criterion for classifying fungi into divisions is their patterns of reproduction Fragmentation – pieces of hyphae broken off a mycelium grow into new mycelia. Unicellular fungi (yeast) reproduce by asexual budding. Most fungi produce spores: specialized mycelium called sporangium. – Protects the spores before being released and keeps them moist
Typical Fungus Reproduction Club-shaped cells that exist in the GILLS of mushroom go through a cycle that produces nuclear fusion spores. The spores, which are like gametes, fuse with other spores to spread the fungus around. meiosis SPORE cap stalk F Spores are released, germinate, and give rise mycelium. gill hyphae of mycelium A cytoplasmic fusion B Spore-bearing mushrooms form from this mycelium. sexual spore forms at gill margin Stepped Art Fig. 24 -12, p. 396
http: //www. yout ube. com/watch? v=i. PO 4 Rry 4 m 4 U &feature=relate d u u Advantage of Spores Protection from dehydration and damage (sporangium) Small & lightweight, can be dispersed by wind, water, animals – Wind can disperse a spore 100 s of miles/kilometers. Produce a large number of spores at one time – A puffball 23 cm in circumference produces about 1 Trillion spores! – Greater survival in numbers Fungi can produce 2 types of spores: – Mitosis (asexual phase) – Meiosis (sexual phase)
Fungal Feeding u There are 3 ways heterotrophic Fungi feed: – Saprophytes are decomposers and feed on waste or dead organic material. – Mutualists live in a symbiotic relationship with another organism like an alga. – Parasites absorb nutrients from the living cells of their hosts u Specialized hyphae called haustoria
Fungi Classification Major Groups of Fungi Take notes on these.
Common Molds Zygomycota u Called “Pin molds” or “sugar molds” u Attack breads & fruits u 900 species u Root-like hyphae called rhizoids penetrate the bread’s surface, stem-like hyphae called stolons run along the bread surface u
Sac Fungi Ascomycotes – have ascus, reproductive structure that contains spores u 30, 000 species u Includes: cup fungi, yeast, morels, truffles u
Club Fungi u u Basidomycotes: “Club fungi” have clubshaped hyphae (basidia) which produce basidospores 25, 000 species Include: puffballs, shelf fungus, mushrooms Puffballs emitting spores You should take care in eating wild mushrooms, many are poisonous!
Imperfect Fungi u u Deuteromycotes: reproduce asexually 25, 000 species Species are varied, can not be assigned to other phyla Includes penicillin, blue cheese veins
Fungi and Humans u Fungi 1. 2. 3. can fall into 3 categories. Beneficial – serve some purpose that we can use to our benefit. Benign – exist as decomposers, productive members of ecosystems. Detrimental – disease to us, animals, or plants.
Beneficial Fungi u Highlights. 1. 2. 3. Food Medicine – Antibiotics like penicillin – Statins: lowers lipids in the blood to reduce chances of heart attacks and strokes Promote plant growth – Lichin – Mycorrhizae: Hyphae of mycorrhizae grow through soil and increase the absorptive area of their partner. – Partner plant provides sugars to fungus.
Fig. 31 -26 Some fungus produce checmials that we use to inhibit bacterial growth. Staphylococcus Penicillium Zone of bacteria’s inhibited growth
A unique fungi: Lichen u u Lichen – a symbiotic association between a fungus & a green alga. Lichen are important as, together, they are the pioneer species that establish ecosystems. Only need light, air, minerals to grow Awesome case of Mutualism… – The photosynthetic alga provides the food for the organism – The fungus provides the alga with water, minerals and protects it from the environment.
How do lichen cells get to islands in the center of the ocean? FYI. Lichen cells break off the original body in microscopic dispersal fragments and can be carried long distances. dispersal fragment (cells of fungus and of photosynthetic species). This is how it spreads through the wind. outer layer of fungal cells photosynthetic species (the little circles) inner layer of loosely woven hyphae outer layer of fungal cells Fig. 24 -14 d, p. 398
Benefits of Mycorrhizae u Juniper seedlings without and with mycorrhizae
Fungal Human Diseases Disease u Ringworm u Valley fever u Athlete’s foot u Yeast infection u Caused by u Fungal parasite u Coccidioides u Fungal parasite u Candida u Fungal diseases are parasitic: They consume the cells of their hosts. u I won’t show you pictures. ew u
Disease (d) Green mold on grapefruit (a) Corn smut on corn (b) Tar spot fungus on maple leaves (c) Ergots on rye • These fungal growths damage plants and crops and destroy food supplies. • Fungi & molds are the biggest obstacle to long term storage of dry grain.
Yeast Respiration Experiment In this experiment, you will observe cellular respiration in yeast. In each of the four test tubes is Bromothymol Blue (turns yellow when it detects cell respiration) kept at 40 degrees Celsius. Test Tube 1 2 3 4 – – Yeast and Sugar Yeast, No Sugar Only No Sugar, No Yeast
Pre-lab Predictions 1. What is the product of cellular respiration that we are trying to detect? 2. What type of respiration occurs in yeast? (Hint: no Oxygen needed!) 3. Name one of the two constants in this experiment. 4. Which test tube # is the control? u Generate now! your hypothesis in your notes
Observe and Reflect u http: //www. youtube. com/watch? v= KTOrp. Hsbs. ZQ u u u Was your hypothesis supported or rejected? – Why or why not? What 3 -letter energy carrier is made through this process for the yeast? How do you think you could get the yeast to undergo more cell respiration?
Answers u 1. Carbon Dioxide Gas u 2. Anaerobic Respiration (Alcoholic Fermentation!) u 3. Bromothymol Blue or Temperature (40°C) u 4. Test Tube #4 is the control u Energy Carrier: ATP (2) u Add more food! – (aka Sugar to the yeast)