Cell wallA thick, rigid wall outside the plasma membrane. In fungi it is built of chitin and glucans, not the cellulose of a plant cell wall.
Plasma membraneThe membrane just inside the wall. In fungi it is stabilized by ergosterol, where an animal cell membrane has cholesterol.
CytoplasmThe filling of the cell. The nucleus, the vacuole and the mitochondria sit in it.
NucleusA membrane-bound nucleus holds the DNA, as in every eukaryotic cell. When the cell buds, the nucleus divides and one copy moves into the bud.
VacuoleA large membrane-bound sac used for storage. Yeast cells store amino acids in it.
MitochondrionIt makes ATP, the cell's main energy-carrying molecule. Fungal cells have mitochondria but no chloroplasts.
Bud and scars 4
Mother cellThe larger cell that the bud grows out of. It can bud again and again, and each bud leaves a scar.
BudA bulge that forms on the side of the mother cell. It grows into a smaller daughter cell, which then separates.
Bud scarScar tissue left on the mother cell where a bud came off. A ring rich in chitin. The number of bud scars shows how many times the cell has divided.
Birth scarMark on a cell where it was once joined to its mother. It is frailer than a bud scar.
How this list was compiled: Every name and detail line was checked on 2026-09-30 against (1) OpenStax Biology 2e, 24.1 Characteristics of Fungi, https://openstax.org/books/biology-2e/pages/24-1-characteristics-of-fungi; (2) OpenStax Microbiology, 5.3 Fungi, https://openstax.org/books/microbiology/pages/5-3-fungi; (3) OpenStax Biology 2e, 4.3 Eukaryotic Cells; (4) Powell, Quain and Smart, Chitin scar breaks in aged Saccharomyces cerevisiae, Microbiology 149 (2003), abstract, PMID 14600225; (5) Wikipedia, Yeast and Budding; (6) Wikipedia, Cell (biology); (7) two journal abstracts on the yeast vacuole read through Europe PMC (PMC13160679, PMC9706634); (8) PMC9041608 (2021), abstract; (9) PMC4968892 (2016), abstract. The detail lines are in our own words. Licence: own work
The drawing: Drawn for this site on 2026-09-30 from plain geometry; nothing traced. Licence: own work
How it works
This yeast cell diagram shows one cell with a bud growing from it. First it is cut open to show the inside. Then it is seen from outside, where earlier buds have left their scars.
Read the full guide
Two views of one cell
Cut open shows the cell wall, the plasma membrane, the cytoplasm, the nucleus, the vacuole and the mitochondria. From outside shows the mother cell, the bud, the bud scars and the birth scar. Tap a name to read about that part, or press Quiz me.
Reading the scars
This is a budding yeast cell diagram, so the scars matter. Each bud that leaves marks the mother cell with a ring rich in chitin, the bud scar. Every cell also carries one birth scar, from the day it was a bud itself.
Count the bud scars: the number shows how many times the cell has divided.
The wall of a yeast cell is built of chitin and glucans; a plant cell wall is built of cellulose.
Questions and answers
Is a yeast cell a fungal cell?
Yes. Yeasts are fungi that live as single cells. Like other fungal cells, a yeast cell has a nucleus, mitochondria, a cell wall with chitin in it, and no chloroplasts.
Does a yeast cell have a nucleus?
Yes. Yeast is a eukaryote, so its DNA is inside a membrane-bound nucleus. During budding the nucleus divides and one copy moves into the bud.
What is a bud scar on a yeast cell?
A ring of chitin-rich scar tissue left on the mother cell where a bud separated. A cell that has budded three times carries three bud scars.
How does a yeast cell reproduce?
Mostly by budding. A bulge forms on the side of the cell, the nucleus divides, and the bud grows and then separates as a smaller daughter cell.