Fungi - Yeast
4 Minutes
Fungi and yeast explained for kids, covering single-celled fungi, yeast cell structure, budding, and bread fermentation. An English science lesson.
- Fungi types and how yeast grows as a unicellular fungus on bread
- Parts of a yeast cell including cell wall, vacuole, and nucleus
- How yeast reproduces by budding and helps bread rise by fermentation
What this lesson teaches
Yeast is a microscopic, single-celled fungus that belongs to the wider group of microorganisms known as fungi. It is an oval-shaped living organism found in the environment and commonly seen growing on foods such as bread.
Inside a yeast cell
- A tough outer cell wall made of chitin gives the oval yeast its form and shields the inside of the cell.
- Jelly-like cytoplasm fills the interior and contains glycogen oil globules that store all the energy the cell needs.
- A large vacuole occupies about twenty percent of the cell space, breaking down proteins into smaller pieces and storing them as nutrients.
- A fully formed, proper nucleus is present inside, which classifies yeast as a eukaryotic organism.
How budding works
Yeast multiplies through an asexual method called budding. During this process, a tiny bud starts to swell and grow on the outer edge of a mature yeast cell. The nucleus inside stretches across the cell and divides into two separate parts. One of these divided nuclei enters the growing bud, which then separates to form a complete, smaller yeast cell.
Fermentation and making bread
Yeast plays an important role in food production through a chemical process called fermentation. During fermentation, yeast consumes glucose sugar and releases carbon dioxide gas. When bakers mix yeast into bread dough, this gas gets trapped and causes the dough to puff up, making the bread soft and fluffy. However, if bread is left out for too long, growing yeast can also cause the food to spoil, covering it with a powdery brown layer.
Key facts about fungi
- Fungi are microorganisms found everywhere in nature, including water, soil, and especially on dead plants and animals.
- Scientists classify fungi into two main groups, which are unicellular single-celled forms and multicellular forms.
- There are roughly 70,000 distinct types of fungi discovered throughout the world.
- Just one small spoonful of yeast can hold nearly ten billion individual yeast cells.
- The specialized branch of science that studies fungi and yeast is known as mycology.