These look like bacterial cells because the cells are unicellular (made of one cell), Bacillus shaped (rod-shaped) and have flagella and pili on their surface. The flagella provide propulsion to help the bacteria move in fluids (such as blood & stomach juices). The flagella 'beat' or move and this helps to move the bacterial cell in a particular direction. This links to the life process of movement. The pili help the bacterial cell to attach to different surfaces and can help to protect the bacterial cell. Bacteria such as the food poisoning bacteria, Salmonella typhimurium and Salmonella enteritidis are two common bacterial species that cause food poisoning.

These look like fungal cells as they are multicellular (made of more than one cell). You can also see structures such as hyphae (which can be used for growth, nutrition and reproduction) and sporangium (spore heads), which are used for fungal reproduction by spore dispersal. You can see that the hyphae form a network called the mycelium. Fungi grow when the conditions are right (moist, warm, and with plenty of food). They reproduce by the repoductive hyphae putting out sporangiophores which develop the swellings we call sporangia. Sporangia make spores by mitosis, meaning each spore is genetically identical. The sporangia dry out and break open. In the process the spores are ejected/flung out and get blown away by the wind to land land somewhere else. Some of the hyphae are feeding hyphae and used in fungal nutrition. These release enzymes onto the food source (which could be a piece of bread, agar on an agar plate, or even human skin). The enzymes break down the food into smaller soluble molecules. These small soluble molecules are absorbed back into the fungus through the hyphae and used to make energy in the life process of respiration. Fungi feed by extracellular digestion.

These look like viral particles. Viruses are not made of cells. They are just made of genetic material (in the centre of the viral particle) surrounded by a protein capsid. On the outside of these viral particles you can also see spike proteins. The genetic material in the centre can either be DNA or RNA. This is used when the virus replicates or multiplies inside host cells. The spike proteins are used to recognise and gain entry into the host cells by combining with chemicals in the surface of the plasma (cell) membrane of the host cell. Viruses replicate by attaching to and entering the host cells, making new viral genetic information in the host cell, making new protein coats, assembling the new viral particles in the host cells, and then releasing the new viral particles by bursting out of the host cell, destroying it in the process.

These look like bacterial cells growing on an agar plate in a petri dish. Only bacteria and fungi can grown on agar plates, as viruses need to be cultured in living hosts cells. The colonies in this image contain thousands and thousands of bacterial cells looking shiny, slimy or greasy. They look like this as bacterial cells have a slime layer or capsule. This capsule has several functions including protection against white blood cells (in anthrax), protection against stomach acid (in salmonella and other food poisoning organisms), and protection from drying out. The agar on the agar plate has the right conditions for bacterial growth. These conditions are warmth (from the incubator), moisture, and nutrients (for nutrition). The nutrients in the agar are used in the process of extracellular digestion. The bacteria release enzymes onto the food source (which in this case is agar on an agar plate, but it could even be human skin or human tissue in the body). The enzymes break down the food into smaller soluble molecules. These small soluble molecules are absorbed back into the bacterium through the plasma (cell) membrane and used to make energy in the life process of respiration. When the conditions are right - warmth from an incubator, moist (from the agar), and nutrients (from the agar) then the bacteria will reproduce asexually very quickly by binary fission (will be discussed in another example). See the section on bacterial growth for more information on that.

These look like fungal colonies on agar. The colonies are fluffy/furry/fuzzy due to the presence of hyphae. As in microbe 2, nutrition and feeding on the agar is by extracellular digestion. In fungi, the hyphae can be used for feeding (nutrition), growing, or reproduction (see microbe 2 above for more detail). You can also just make out sporangia in the photo of the fungal colonies, which are used for reproduction. The conditions for fungal growth and reproduction are ideal. There are plenty of nutrients on the nutrient agar, there is moisture in the agar, and the agar plates were incubated in the warmth. See the pages on fungal nutrition, fungal growth and fungal reproduction for more details.

This looks like a fungal infection of the skin of the feet, such as Athlete's foot (also known as Tinea pedis), and is often caused by the dermatophyte fungus called Trichophyton rubrum. The fungus lives & spends part of its life cycle on the skin, especially on the skin of the feet in between the toes. There it feeds on the nutrients in the skin, grows and reproduces. If the skin is moist from sweat or not kept clean, it can provide the ideal conditions for the fungus to feed, grow and reproduce. Feet get sore, cracked, itchy and scaly skin on the feet, especially between the toes. This infection can also spread to the nails as well. The fungi have warmth, moisture and nutrients from the skin cells of the feet. Fungal spores from T. rubrum can live on the scales of the skin for 12 months. This makes them likely to be transmitted from an infected person to an uninfected person in places such as public showers and locker rooms. In order to prevent infection you should keep your feet clean and dry, regularly change socks and trainers, prevent feet getting too sweaty etc. Althlete's foot can be treated using special antifungal powders e.g. mycil, or creams and ointments such as miconazole, and sometimes tablets.

This looks like bacteria growing on agar plates which have got five different antibiotic discs on them. Around the five antibiotic discs you can see clear zones of no growth, called zones of inhibition. Bacteria are killed or their growth is inhibited by the different antibiotics. The antibiotics discs with the biggest zone of inhibition are better at preventing bacterial growth. Antibiotics are substances produced by fungi that kill bacteria. Antibiotics are used to treat bacterial infections. The complete course of antibiotics should be taken by patients prescribed them by their doctor. Not completing the course of treatment, the over prescription of antibiotics can all lead to the development of antibiotic resistant strains of bacteria. Antibiotics do not kill viruses, so should not be used to treat viral infections.