Basic structure
This diagram on the left is of a Rhizopus - a common mold. The hyphae grow around and into food such as bread and rotting fruit, and is where the food is broken down by the fungi. The sporangium is the reproductive organ of the fungi, producing spores which contain the genetic material required to make a new fungi.
Below is a spoon full of yeast - a unicellular fungi. Yeast is very useful for cooking! |
Helpful vs. harmful fungi
Helpful |
Harmful |
We eat lots of fungi! We eat mushrooms and bread, drink ginger beer and (if your parents let you) wine. These things are all made using particular forms of fungi! |
Fungi has the capacity to spoil food (think of mold growing on bread and cheese) - eating foods with particular mold on them can be very dangerous. |
Many antibiotics are produced by fungi - for example, penicillin - this can kill harmful bacteria and help us recover from infections! |
Fungi can grow on us, and give us a bit of grief For example, athletes foot and thrush - both are skin infections caused by fungi. |
Most fungi are decomposers (making them saprotrophs), making them very useful in nature as they break down dead/decaying matter and release the nutrients from them back into the environment! |
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LIFE PROCESSES
N E R R G
Nutrition
All fungi are heterotrophic.
This means they all must obtain nutrients from eating and digesting other organic matter, as they cannot make it themselves!
This means they all must obtain nutrients from eating and digesting other organic matter, as they cannot make it themselves!
Saprotrophs
Lots of fungi are saprotrophic - they feed of dead or decaying matter. This is helpful for the environment because the fungi are releasing nutrients that would otherwise stay locked up in that dead matter. This helps with nutrient recycling!
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Parasites
Some fungi can be parasitic - meaning they feed off LIVING organisms, causing harm to them while the fungi benefits. Things like athletes foot - this is a parasitic relationship between fungi and humans!
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Like bacteria, fungi also use extracellular digestion to obtain nutrients from their food source. Extracellular means outside of the cell therefore the breakdown of nutrients actually occurs outside the fungi.
Excretion
Their waste can be pretty life-saving!
All cells produce waste products - it is all a part of 'living' - when cells undergo respiration (below) they make products they use, and waste products that need to be discarded. Fungi are particularly useful to humans due to the waste products they make during respiration.
Waste is excreted via the hyphae. Like bacterial waste, the waste produced by fungi can be harmful or helpful.
Waste is excreted via the hyphae. Like bacterial waste, the waste produced by fungi can be harmful or helpful.
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Respiration
Making useable energy using enzymes.
Most fungi respire aerobically.
Aerobic respiration is far more efficient (makes more energy) than anaerobic - so whenever there's oxygen around, fungi will default to this type.
The equation for aerobic respiration is: Glucose + Oxygen → ATP + Carbon dioxide + Water
(carbon dioxide and water are waste products - must be excreted) |
When oxygen is unavailable, fungi will undergo anaerobic respiration.
For example, fungi that live in the gut of particular herbivores, or yeast that is being used to make bread dough.
Glucose → ATP + Ethanol + Carbon dioxide
This process is also called fermentation. (ethanol is a waste product - must be excreted - is what helps make alcohol) |
Growth
Fungi must grow before they can reproduce.
- Fungi must obtain enough nutrients in order to respire.
- If fungi cannot undergo respiration, they are unable to make ATP (energy).
- Without energy, fungi cannot grow any bigger.
Reproduction
Asexual reproduction ftw!
Most fungi reproduce asexually - this is a very quick method compared to sexual reproduction!
Spores
Rhizopus, a multicellular fungi, reproduces using spores. These are produced when some hyphae grow upwards and develop a sporangium at their tip. The sporangium is full of spores which are released into the wind so they can be dispersed to a new place, where they won't have to compete for food! Spores contain identical genetic material to the original fungi, making this method of reproduction asexual. Spores can withstand drying out because of their waterproof outer layer. When a spore lands on an appropriate food source, it germinates (starts to grow).
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Budding
Unicellular fungi, such as yeast, reproduce using a method called budding. This is when the DNA inside the cell is copied, and the cell grows larger in size until the original cell has a growth on similar size on it. This can then break off and produce a new cell, containing its own DNA. As the DNA is identical in both cells, this is also asexual reproduction.
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Think about it...
Why does bread only rise if you leave it somewhere warm for a few hours?
How does leaving dough out on the bench affect the life processes of yeast (a fungi) and how does this make bread rise?
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