3.1.4 Fungi Living things Monera Protista Fungi Plants Animals

Classification of organisms Living things are divided into five Kingdoms: Living things Monera Protista Fungi Plants Animals Necessary due to the large number of organisms in the world – makes it easier to manage – like our wardrobe. Every single living thing must fit into one of these groups. Kingdoms!

The Fungi Include moulds, yeasts, lichens and mushrooms Mainly terrestrial – live dead or living plants/animals and found in the soil Moulds are microscopic fungi Yeasts are single celled fungi Lichens are fungi

Fungi can be edible or poisonous! The Death cap fungus causes liver failure and death Standard Field mushrooms are safe to eat Death cap mushroom is found in European woods and in north America

The Fly agaric mushroom sends toxins into the central nervous system and cause hallucinations

Identifying mushrooms To identify mushrooms… Use a key to classify them Look at their colours, patterns and shapes! Smell them!

Nutrition in Fungi Heterotrophic Saprophytic Parasitic Feed on dead organic matter Feed on live hosts the fungus that causes Athletes foot feeds on live human flesh Rhizopus fungus feeds on bread.

Parasitic Fungi

Rhizopus A microorganism is any tiny organism

Structure of Rhizopus Sporangium where spores are made Spores cells that can germinate to produce a new mycellium Columella wall at base of Sporangium Apophysis Sporangiophores Stalks of hyphae whose tips have swellings called sporangia Stolon Hyphae that spread across the substrate Not necessray to know the functions Apophysis - Area where stolon meets columella Hyphae Thread like structures that digest and absorb the substrate Mycelium A group of Hyphae Rhizoids Root like hyphae which provide extra surface area to absorb the substrate

Rhizopus – Asexual Reproduction 1. A Sporangiophore grows upwards and forms a sporangium. 2. Within the sporangium mitosis occurs to produce lots of cells. 3. When each cell develops a resistant wall is becomes a spore. 4. Spores are dispersed by the wind 5. When spores fall on a suitable substrate they germinate and produce new mycelia. Sporangium Spores Columella Apophysis Sporangiophore Mycelium

Put them in the correct order When spores fall on a suitable substrate they germinate and produce new mycelia. Within the sporangium mitosis occurs to produce a mass of cells. Spores are dispersed by the wind A Sporangiophore grows upwards and forms a sporangium. When each cell develops a resistant wall is becomes a spore.

Sexual reproduction + Strain - Strain

Sexual reproduction + Strain - Strain

Sexual reproduction + Strain - Strain

Sexual reproduction + Strain - Strain

Sexual reproduction + Strain - Strain

Sexual reproduction + Strain - Strain

Sexual reproduction + Strain - Strain

Sexual reproduction

Rhizopus – Sexual Reproduction Production of Progametangia The hyphae from different mycelia produce bulges called Progametangia which grow towards each other

Rhizopus – Sexual Reproduction Suspensor The cross wall blocks off each tip form each other 2. Formation of gametangia and suspensors The stalk of each Prometangia is called a suspensor and the tip is called gametangia.

Rhizopus – Sexual Reproduction The cell wall dissolves 3. Formation of zygospore The gametangia fuse to form a zygospore

Rhizopus – Sexual Reproduction Sporangiophore Zygospore Zygot with a thick wall - zygospore 4. Germination of zygospore The zygospore may remain dormant , but when favourable conditions return it germinates to make a sporangiophore with a sporangium at it’s tip.

Yeasts Yeasts are also part of the Fungi Kingdom They are unicellular. Cell wall Nucleus Vacuole Ceusually found on the surfaces of leaces, flowers, fruites, milk,animal faeces Vacuole – like in a plant cell! About 10 um long Can be seen with an electron microscope Granular cytoplasm Food vacuole

Asexual reproduction in yeast

Asexual reproduction in yeast

Asexual reproduction in yeast

Yeast – reproduction by budding A small _________ is formed on the cell This ________ gets __________and is filled with cytoplasm The nucleus of the parent cell ____________ by _______ One of the nuclei formed moves into the bud which can break free of the parent and form a new __________itself Parent cell Bud Bud Bud Bud Daughter cell Mitosis

Yeast – reproduction by budding Or the bud may remain _____________ to the parent cell and form a _____________ of attached cells which eventually divide Parent cell Bud Bud Bud Bud Daughter cell Mitosis Unseperated buds

Budding

Budding

Laboratory Procedures when handling microorganisms Sterilise your working area, all of your equipment and materials before and after using it Upside down prevents condensation from getting on the lids An autoclave is used to sterilise glassware, agar and instruments!

Laboratory Procedures when handling microorganisms 2. Flame metal apparatus during use 3.Seal the Petri dishes with tape AND turn it upside down before incubation! 4. Sterilise all cultures before disposal

Lab procedures when handling microorganisms Sterile means absence of all the microorganisms Aseptic means free of pathogenic microorganisms.

Keywords for mircobiology Sterile means absence of all the microorganisms Aspetic means free of pathogenic microorganisms.

Fungi Fungi are economically very important.. In the food industry… Bakers use yeast to produce CO2 for raising bread, In the healthcare industry… Penicillium fungi are used to make penicillin, a widely used antibiotic. Thenaol is a by product of anaerobic respiration in yeast Also mushrooms are edible, poisononous mushrooms need medical care!

Fungi Fungi can also be economically harmful.. In the food industry… Rhizopus mould causes food spoil e.g. bread, fruit In the healthcare industry… Athletes foot is caused by a fungus that feeds on warm, damp tissue between your toes! - expenses in medical care! Athletes foot causes skin to go scaly, red and ithcy!

3.1.10 Growth Curves Higher Level

3.1.10 Growth curves Any microorganism – typical population of bacteria would look like this – you would have to count the numbers in the population at fixed intervals

Growth curves -Lag phase The microorganisms are adapting to their new environment and must produce the enzymes needed to digest the available nutrients here. There is little increase in numbers. Lag phase

Growth curves -Log phase The microorganisms reproduce at their maximum rate so their numbers rise rapidly. They now have ideal conditions to live in – lots of food, space and little toxic wastes around. Log phase

Growth curves -Stationary phase There is no increase or decrease in the number of microorganisms because equal numbers are being produced and dying. Food and space may now be scarce and toxic waste products may poison the organisms. Stationary phase

Growth curves - Decline phase Due to lack of Food and space and the build up of toxic waste products more microorganisms are now dying than are being produced. Population numbers fall. Decline phase

Growth curves –The survival stage Not all of the population of microorganisms will die. Some will form endospores when unfavourable conditions persist. The endospores may remain dormant for many years before favourable conditions return. At this point the endospores will undergo binary fission and reproduce. Survival phase

What did you learn? What are the five stages of microorganism growth? Why do microorganisms grow slowly during the lag stage? What happens during the log stage? Why do microorganisms numbers stay the same during the stationary phase? What is the name of the stge that comes after the stationary phase?

Bioprocessing It can be very useful to grow populations of microorganisms as they can be used to produce food products, antibiotics, enzymes, insulin and other substances. Microorganisms are used to do reactions in large sterilised containers called Bioreactors. Bioprocessing Need to know the two types of processing only Batch flow processing Continuous flow processing

Batch Flow processing Survival phase Nutrient medium and microorganisms put in the Bioreactor. Most product is produced at lag, log and stationary phases. Process stopped after stationary phase, product is extracted, filtered and purified Bioreactor is cleaned, sterilised and the process is restarted Stationary phase Decline phase Lag phase Log phase

Batch Flow processing

Continuous flow processing Survival phase Nutrient medium and microorganisms put in the Bioreactor. Nutrients continuously fed into the bioreactor and culture medium taken out – organisms stay in the log phase as conditions do not change Stationary phase Decline phase Log phase Lag phase

Continuous flow processing The Bioreactor

What did you learn? What are the five stages of microorganism growth? Why do microorganisms grow slowly during the lag stage? What happens during the log stage? Why do microorganisms numbers stay the same during the stationary phase? What is the name of the stge that comes after the stationary phase?