Biology Basics: Important Components of Eukaryotic Cells

By Rene Fester Kratz

Part of Biology Workbook For Dummies Cheat Sheet

For biology students, knowing the components of eukaryotic cells and how they work is fundamental to understanding how organisms function. This table provides an overview of the most important eukaryotic cell structures and functions and how to recognize them.

Structure Function How to Recognize
Cell wall Rigid boundary around some cells Outermost boundary in plant, algal, fungal, and bacterial
cells. Cells with a cell wall are usually very regular in shape,
like they’ve been cut with a cookie cutter.
Chloroplasts Make food, transferring energy from sun to food molecules Organelles with two membranes and internal stacks of membranes
called grana, which look like layers of stripes.
Cytoskeleton Reinforces cell structures; helps move materials around
Looks like cables running through the cell.
Endoplasmic reticulum (ER) Rough ER has ribosomes, makes proteins; smooth ER makes
Folded sheets of membrane that ripple off of the nucleus of
cells. The rough ER has ribosomes stuck to it, so has a speckled
appearance. Smooth ER may look tubular, like coral, and has an
unspeckled surface.
Golgi Receives molecules from ER and modifies, tags, and ships them
Looks like a stack of pancakes surrounded by little membrane
Lysosomes Break down worn-out cell parts Small spheres within the cell; may contain partially broken
down materials.
Mitochondria Transfer energy from food to useful form for cells (ATP) Organelles with two membranes. The inner membrane is crinkled
into folds called cristae.
Nucleus Houses the genetic material Largest organelle, surrounded by a double membrane that has
little holes in it. May contain dark spots called
Plasma membrane Selective boundary of cell Outermost boundary in animal cells. Cells that have only a
plasma membrane for their boundary may be variable in shape.
Ribosomes Where proteins are made Look like tiny dots in the cell. May be loose in the cytoplasm
or attached to the rough endoplasmic reticulum.