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Microbes Week

Period: 8-14 June 2020

Welcome to Microbes week!

Over the next 5 days we’ll be exploring the amazing world of life at the far end of the microscope. While many of the things we’ll be looking at are too small to see without help, they have a huge impact in the world.

The information and activities for this week have been written by researchers from the University of Dundee School of Life Sciences. You will be able to read some more about the important work that they do and even meet a few of them later this week!



Welcome To Microbes Week

Oh, hai! It’s nice to meet you all!

There are a few key words you’ll need to know as we kick off. A microbe can also be called a micro-organism. Micro means small. What then, is an organism?

Fun Fact: You are one! So are dogs, cats, and all animals. Plants are organisms, and so are fungi. In fact, an individual of anything that’s alive is an organism.

Micro-organisms might be tiny, but they come in a variety of shapes and (small) sizes. They live in a dazzling array of different places on the Earth, including on your skin and in your intestines!

Bacteria (bak·teeuh·ree·uh) are the best known of the microbes. They are very distantly related to humans, so their cells are very different to ours. We can find them in lots of places...in the soil, in our food, or even inside us! Some are harmful, but lots of them are super helpful.

Archaea (are-key-ah) are a very ancient form of life. Like bacteria they can live in extreme environment, like the bottom of the sea, or in geothermal vents but they are also found in your bellybutton!

Find out more about archaea by watching the video below.

Eukaryotic (you-carry-oat-ick) microbes have cells with the same structure as ours. They include organisms like fungus, which can be helpful. Humans use a fungus called yeast to help them make different types of food. Mould, like the kind you grew in Body Bits Week, is a fungus as well. Eukaryotic microbes also include disease-causing parasites like Plasmodium falciparum, which causes malaria.

Challenge: Try our Word Finder Challenge! How many different words can you make using the letters in “micro-organism”? We’ll start you off with the word “magic”! Now your turn. Let us know how you get on.

Challenge: Lichen Hunt

Lichens are a group of organisms that sit with us as part of the eukaryotes. They are in fact made of two types of eukaryote working together:

  • Algae
  • Fungi

They often have different properties than the things that make them. They can survive in lots of different places and often have fascinating colours and patterns.

What do I do?

Next time you go out for your daily exercise, see how many different types of lichen you can find. You can look at trees, walls, signs, pavements, roof tiles, LOTS of places!

Nicola Stanley-Wall, a professor of microbiology at the University of Dundee, did her own lichen hunt with her family on their daily walk. Check out the photos! They found lichen on the pavement and street signs.

Can you find lichen?

If you do, take a picture and enter it into this week's competition!

Upload Your Photograph

Meet the Scientist – Diana Gudynaite

“Last year, I completed Master’s degree in Biotechnology in Ireland and moved to Dundee to work as a research assistant at the Universities’ molecular microbiology department. We are currently investigating how Bacillus subtilis bacteria can sense stress.

Why is this important? Well, some foods contain preservatives which prevent microbial growth, but sometimes the microbes still survive! Harmful bacteria such as Listeria monocytogenes have similar stress coping mechanisms and therefore it is important to understand how they work, to prevent their survival in our food and causing us any harm.”

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No.721456.

Diana Gudynaite
Diana Gudynaite - Diana in the laboratory!
Diana Gudynaite
Diana Gudynaite - Diana on a lichen hunt!

Microbes Shapes and Sizes

Let's see how bacteria and parasites look. They are both single-cell organisms that come in a variety of shapes and sizes. Both types of microorganisms are very adaptable and can live in almost all environments, partially due to the protective features that help them to survive and thrive.

A typical bacterial cell has a protective wall surrounding it. Some have flagella which act as propellers to let the bacteria swim to find food and some are covered in dozens of tiny hairs called pili to help them stick to surfaces.

Bacteria are classified into five groups according to their basic shapes and they can exist as single cells, in pairs, chains or clusters.

  • round (coccus)
  • rod (bacillus)
  • comma (vibrio)
  • spiral (spirillum)
  • corkscrew (spirochaetes)

The cartoon below shows some of the common shapes.

Common Bacterial Shapes
Common bacterial shapes (Credit to Janice Haney Carr, Center for Disease Control and Prevention and Oregon State University)

Similarly, some parasites also have ability to move and propel forward. For example, amoeba organisms (Eukaryotic) can change their shape by extending little feet-like projections used for feeding (see image).

Scales and Sizes

As some microbes are very small, we use microscopes to look at them. The smallest object the human eye can see without magnification is about 100 µm (µm stands for micrometer) in diameter. For reference, a printed full stop in a newspaper is about 300 µm in diameter.

Units of length we commonly use in biology span a wide range of scale:

Metric unitMeaning of measurements
Centimetre (cm)1/100 m or 0.01 m
Millimetre (mm)1/1000 m or 0.001 m
Micrometre (µm)1/1,000,000 m or 0.000001 m
Nanometre (nm)1/1,000,000,000 m or 0.000000001 m

Activity: Now try our Scales and Sizes worksheet.
An Amoeba Reaching Out of Food
An Amoeba Reaching Out of Food
Scales and Sizes Worksheet
Scales and Sizes (PDF) and Answers

Competition: Design Your Own Microbe

What shape is it? Does it have any adaptations to help it survive in the environment? Is it a harmful or beneficial microbe? If it’s a helpful microbe, what is it used for? Be sure to name your microbe. You could make a news story about your discovery!

Ideas for the craft - you can choose to model your microbe from:

  • Playdough, salt dough etc.
  • Draw it or use felt/crotchet techniques if available
  • Recycle any cardboard or plastic material in your house

If you are stuck for inspiration - google the word microbe and check the images section.

Make sure to submit the picture of your microbe with its name and what it does for our weekly competition.

Microbes In Nature: Believe It or Not

Microbes are everywhere and do lots of different jobs. Here are some believe it or not facts about some microbes in nature:

Leaf-cutter ants: microbes – friend or foe?

During Mini-beasts week you watched videos featuring the leaf-cutter ants. Did you know that leaf-cutter ants are expert farmers? These special ants go on long journeys to find fresh pieces of leaves that they use to grow a white nutritious fungus, Leucoagaricus gonglyophorous, for their food. See how they make it by watching this video.

Along the way of leaf hunting, leaf-cutter ants can encounter the harmful fungus named Escovopsis that can destroy their fungus food! Thankfully, the ants are equipped with helpful bacteria that live on their bodies and can kill the harmful fungus.

Some scientists are studying leaf-cutter ants as they have been making their own antibiotics for millions of years without the worry of resistance. You can learn more about this work led by Matt Hutchings, a Professor of Molecular Microbiology at the University of East Anglia:

You will learn more about antibiotics on Friday, and how scientists are trying to find new ones all the time.

Before you see rain, do you smell it? It’s thanks to microbes!

Have you ever noticed a fresh musky smell just before or after it has rained? Rain doesn’t smell so where does this smell come from? It comes from compounds called petrichor that have been produced by living things when it is dry.

A microbe called actinobacteria are one of the main contributors to this smell. They make a compound called geosmin when they decompose dead or decaying organic matter. When it rains, the raindrops dissolve the geosmin and release it as an aerosol (mist) which fills the air – it works a bit like when you spray air freshener or perfume. As the wind can carry this smell, it might mean you can smell the petrichor before you see the rain!

Rain In The Gardent
Rain In The Garden

Sea Creatures and Their Protector Microbes

Predators are a danger to many animals, so they have developed ways to keep themselves safe.

The Hawaiian bobtail squid hunt for food at night to hide from predators. They turn on colourful lights inside their bodies to attract prey and to prevent shadows appearing underneath them. The light is provided by bacteria Vibrio fischeri inside their body that lives happily there causing no harm!

Check out the first minute of this video where microbiologist Dr Siouxsie Wiles, an Associate Professor and head of the Bioluminescent Superbugs Lab at the University of Auckland, New Zealand (she did her degree at the University of Edinburgh!), explains how the light that the Hawaiian bobtail squid makes camouflages them:

YouTube Video: The Hawaiian bobtail squid - when science and nature collide

The blue-ringed octopus lives deep in the sea. They can protect themselves from the prey by first poisoning and then eating it. But they cannot make the toxic substance on their own… they need bacteria called Vibrio to make the toxin, which lives in their saliva.

The blue-ringed octopus sends out a warning signal to tell predators that it is poisonous. Check out this video of a blue-lined octopus, a member of the blue-ringed octopus group, to see what this signal is:

Blue Ringed Octopus

These are examples of a symbiotic relationship – where the microbe lives together with the other species. In these cases, one species (the leaf-cutter ant, the squid or the octopus) benefits from the other (the microbe) but no harm is caused to either of them. Not every symbiotic relationship is helpful.

In our final fact, we return to lichens, which you hunted for earlier this week, they are another example of a symbiotic relationship.

The origin of plants is thanks to microbes

Watch this video which features Chris, one of our microbiologists, as he explains why plants are green!

Chris Earl
Meet the Scientist - Chris Earl

Chris Earl was born in Dundee and completed a Molecular Biology degree and a Ph.D. in Microbiology both at the University of Dundee. Still based here, Chris is now investigating how some species of bacteria can inject toxins into other bacteria to kill them. The benefit of this, is that by removing competitors from the environment the bacteria now no longer compete for the same scarce, vital nutrients. These toxins may one day be used by humans as antibiotics to kill harmful bacteria which cause human disease.

Explore A Virtual Laboratory

We do lots of world-leading research at the University of Dundee. In our laboratories, we can grow different cells, test chemicals, and explore how molecules work.

One thing we can’t do very easily, sadly, is let people freely explore our labs. There’s lots of equipment in there, and some of the chemicals and cells can be dangerous. If we want to research the deadly disease malaria, for example, we must keep it in our labs. Safety is incredibly important, so only people who have been fully trained can come in.

Fear not! There are a couple of ways you can discover our labs from the comfort of your own home.

We’ve set our labs up on Google Street View so that you can tour them from the comfort and safety of your own home. Take a look at our worksheet to find out how.

Challenge: Where’s Ally?

One of our team seems to pop up a lot. He may be the result of a hideous cloning experiment gone wrong, or perhaps he’s just enthusiastic. He has a beard, red sneakers and a fabulous manbun. How many of him can you find?

Use a pen and paper to make a tally chart to count how many times you see him. To do this, draw a line each time you see Ali. When you get to the fifth line, draw it through the first four. Then repeat this until you have found all the Ail’s. This makes it easier to count at the end.

While searching for Ali and exploring our labs, see if you can also answer these questions:

  • What safety equipment are people wearing?
  • Is the safety equipment the same in all areas? What’s different (look at lab coat colours…)?
  • Can you see any robots? (almost all our robots are big grey boxes!)
  • Can you see any interesting glassware in the labs? The chemistry side of the laboratory might be good for that search.
  • We use a lot of the same cleaning products as at home. Can you find any?

You can find out much more about our labs at

Household Microbes

You’ve learned all about how microbes live all over the world, all around us. But did you know that you can also find them in your own home? Humans have harnessed microbes to do all sorts of useful jobs for them.

Challenge: Scavenger Hunt

Here’s a scavenger hunt for you to do – if you can’t find something in your house why not draw a picture?

  • Yeast or bread
  • Cheese or yogurt
  • Biological washing powder
  • Vinegar
  • Chocolate
  • Quorn

Want to learn more? Here’s some facts about the microbes behind these useful and sometimes tasty products!



Bread is made using baker’s yeast, which you might remember is a type of fungus, a eukaryotic microbe. The proteins (called enzymes) made by the yeast break down the large flour molecules into sugars. The sugar is converted to carbon dioxide and alcohol and the carbon dioxide is trapped within the dough causing it to rise and take on a bubbly structure.


Yogurt is a fermented milk product. The sugar in the milk (lactose) is converted to lactic acid by lactic acid bacteria which makes the milk thicken. Flavours can then be added. Lactococcus lactis and Bifidobacterium are common bacteria used in this process.


Like yogurt and sour cream, cheese is made from milk that contains the sugar lactose and a protein called casein. During cheese production the lactose is converted to lactic acid and the protein is thickened. Water is removed, leaving a semi-solid product. This relies on fermentation using lactic acid bacteria. Cheese also needs ripening to give it flavour. This also uses bacteria and depending on the exact mix of the microbes used the flavour can be very different.
Washing Powder

Washing Powder

Biological washing powders contain enzymes that are made by bacteria. Bacteria do not have a “stomach” but instead make enzymes that they put into the environment around them. Here they break down the food into smaller parts that can be taken up and used. We have adopted this for washing powders where the enzymes help to break down the food on our dirty clothes.


Vinegar is a solution that is mainly acetic acid. This is produced by fermentation of ethanol by acetic acid bacteria. This is also what happens to make cider, wine etc.


Cocoa beans are seeds that form inside pods. They are coated in a sugary material that needs breaking down. Microbes help with this. The beans are “fermented” and this makes the bean taste chocolatey. (A similar process is used for making coffee beans).


Quorn is a meat substitute that is made from a fungus called Fusarium venenatum. The fungus grows in large tanks and then is collected and dried.

Here’s a video from TED-Ed that will tell you all about these tasty treats and more.


In the picture, you can see the most common bread yeast, Saccharomyces cerevisiae, as viewed under a microscope. This image was taken by scientist Viola Denninger (Tanaka Lab, University of Dundee) who uses yeast in her experiments.

We will investigate yeast a little bit more. Yeast is a microbe that is contained in dough and is needed to make bread rise. Yeast turns sugars in the dough into alcohol and a gas called carbon dioxide in a process called fermentation. As the dough heats up the bubbles of gas get bigger and the bread rises.

Activity: Today you will test the best way to make yeast grow with our experiment Yeast Races! The goal is to compare which food is best suited for yeast to make the bread rise.
Yeast Races Worksheet
Yeast Races (PDF)

10. Treating Infections with Antimicrobials

Throughout the week we have been looking at the marvellous and amazing roles that microbes play in shaping our world and our lives. However, some microbes can cause human or animal infections. Just now, many scientists are working very hard to find new ways to treat the virus called Sars-CoV-2, a coronavirus that causes COVID-19.

“Antimicrobials” are substances that kill a microbe or stop it from replicating (making more copies of itself). Antimicrobials can be split into different classes depending on which type of microbe they target.

For example:

  • Antivirals target viruses
  • Antibiotics target bacteria
  • Antifungals target fungi
  • Antiparasitics target parasites

Antimicrobials are an important part of modern medicine. For example, without effective antibiotics many common surgeries and accidents could become life threatening. Did you know that Scottish biologist and doctor Sir Alexander Fleming was involved in the development of penicillin, an antibiotic that we still use today?

Watch this video to learn more about “The accident that led to penicillin”:

The Accident That Changed The World

Our friends at the National Museum of Scotland have some amazing objects in this area, including samples of penicillin mould donated by Sir Alexander. Find our more by visiting.

You can also learn more about key dates in the history of antibiotics by downloading and reading

Activity: Antibiotic Timeline - Why don’t you make your own antibiotic timeline and share it with us? You could pick eight key events that you want to highlight.

Antimicrobial Resistance

Antimicrobials are amazing tools for treating many different infections. However, over time microbes can develop ways to resist the medicines, which means the antimicrobial will no longer work – this is called resistance. The resistance can happen naturally as microbes reproduce very quickly and change to allow them to grow in the presence of the medicine. Because antimicrobials are used a lot in medicine and agriculture this has made them change more quickly. Therefore, it is very important only to take antibiotics (and other medicines) when you are told to by a doctor and to follow the prescription guidance.

Making New Antimicrobials

There are two main routes that scientists use to develop new antimicrobial compounds.

One involves taking inspiration from nature. You found out on Wednesday that leaf-cutter ants carry microbes to help keep their fungal gardens clean. Many bacteria make antibiotics to fight off other microbes that live in the surrounding area. This means that they can keep food and other resources to themselves.

Bacteria that live in the soil are especially good at making antibiotics. In fact, the first antibiotic that was identified from a soil bacterium was tetracycline which was initially used in 1948. In the image below you can see bacteria that have been isolated from soil by pupils from Baldragon Academy, Dundee. In this sample the pupils found one bacterium that protected the surrounding area from invasion by the other microbes and formed a cleared halo around it - can you see it? Lots of scientists are looking for new antibiotics using bacteria from many different habitats.

There is even a chance to look for new antibiotics in places you choose (£):

At the University of Dundee, we are also specially placed to use another route to make new medicines.

Most new medicines are made by big companies. It’s a very expensive process, which needs skilled people and complex robots. They can only afford to research medicines they think will make a profit. In a university, we can research things that we think are important to society, whether they make money or not. Having a medicine-making company as part of a university means we can get the best of both worlds. We can research important medicines to help people without a lot of money at our Drug Discovery Unit. No one else in the world works the way we do, and we’re very proud of it.

Our team of biologists can take existing molecules and test them to see if they work against infection-causing microbes – and make sure they don’t hurt people. Our medicinal chemists can then change the shape of the molecule to try and improve it. They can add on atoms in different places, based on what they know about how the shapes work. Together, the teams run a cycle of design, make and test, design make and test.

So far, we’ve made two really exiting potential medicines to fight parasites. One fights malaria, a disease lots of people have heard of, and the other is for leishmaniasis. This horrible parasite is not as well known – in fact, it’s classed as a Neglected Tropical Disease by the World Health Organisation.

Some of our scientists have written a free book for young people where you can find out more about Leishmania - it’s called Kirsty’s Story.

Why don’t you take a look?

Activity: Download our Antimicrobial Word Search. Can you find all the words in this word search? Look closely.
Antimicrobial Word Search (PDF)
Antimicrobial Word Search (PDF) Answers (PDF)
Petri Dish
Petri Dish

Also see our other Home Learning Topics information and our Learning Resources.

If you have enjoyed these activities please share them with your friends and family.