Topic 2.4

What are fungi, yeast and parasites?

 Step into the intriguing world of fungi, yeast, and parasites—organisms that play unique roles in our lives and health. You’ll learn about the fascinating structures and functions of fungi. Yeast, a single-celled fungus, can be helpful and harmful, while parasites like head lice and tapeworms rely on a host to survive.

Fungi

Fungi are a diverse group of organisms that can often be observed without a microscope. Common examples of fungal infections include mould, which can be found growing on damp surfaces, and athlete’s foot, a condition that affects the skin on the feet. One of the most widely recognised types of fungus is yeast.

Yeast is a single-celled organism that plays a crucial role in various culinary processes, particularly in the fermentation of beer and the leavening of bread. It helps the dough rise by producing carbon dioxide. While yeast is beneficial in many ways, it can also cause infections, especially in certain individuals.

 

Yeast Cell Structure

Yeast Cells are simple with four main parts:

  1. Cell Wall: Helps maintain shape and prevents bursting
  2. Nucleus: contains genetic material that controls the replication of the cell
  3. Cytoplasm: Where chemical reactions of the cell take place.
  4. Bud: New yeast cell

Parasites

Not everything that carries a disease is a micro-organism. A parasite is an organism that lives in or on another organism – the other organism is called the host. Parasites can include:

1. Head-lice
2. Fleas
3. Tapeworms

These can live inside or outside the body.

Head-lice

Head lice are tiny, wingless insects that infest the scalp, feeding on human blood and causing itching. They lay eggs, or nits, on hair shafts and are most common in children.

Fleas

Fleas are tiny, external parasites that primarily feed on the blood of mammals and birds. They can cause significant discomfort and irritation to their hosts and can also transmit diseases.

Tapeworms

Tapeworms are parasitic flatworms that can inhabit the intestines of various animals, including humans, and are known for their ability to absorb nutrients from their host’s food.

Activity

Discuss as a class what online sources of information would be the most reliable when researching pathogens. Working in pairs and using reliable sources, research one of the following diseases:

  • Giardiasis
  • Invasive Pneumococcal Disease
  • Norovirus disease
  • Athlete’s foot (tinea pedis)

For your chosen disease, answer the following questions, listing the information sources you used, explaining why you felt each was a reliable source

  1. What kind of pathogen causes the disease?
  2. How does the pathogen enter the body?
  3. What are the symptoms?
  4. How is it treated?
Topic 2.3
Topic 2.5