How to label a cell diagram and remember every part

Start with the big three

On any cell diagram, find the outline, the nucleus and the cytoplasm first. The outline is the cell membrane; if there is a thick second border around it, that is the cell wall and you are looking at a plant cell. The large round shape near the middle is the nucleus, and the darker spot inside it is the nucleolus. Everything else floats in the cytoplasm. Labeling these first gives you five easy points and a frame for the rest.

Use shape clues for the rest

Most organelles have a shape that gives them away, even in a simplified drawing.

• Mitochondria: bean or oval shapes with a wavy or zigzag line inside.
• Chloroplasts: green ovals with stacks of small discs inside.
• Golgi apparatus: a stack of curved, flattened sacs, often with small bubbles at the ends.
• Rough ER: folded bands near the nucleus covered with dots.
• Smooth ER: similar tubes without dots.
• Ribosomes: the dots themselves, on the rough ER or loose in the cytoplasm.
• Central vacuole: the largest shape in a plant cell, often pale blue.

Tell the look-alikes apart

Lysosomes, peroxisomes and vesicles are all small round sacs. Vesicles usually cluster near the Golgi or the membrane. Lysosomes are often drawn with dots or granules inside. Peroxisomes may show a darker core. If a diagram is unclear, use position: vesicles travel between the Golgi and the membrane, while lysosomes sit out in the cytoplasm.

Practice with the labels hidden

Recognizing a labeled diagram is easier than producing the names yourself. On this site, switch the labels to numbers and say each name before checking, then try the ten-question quiz. Print the blank worksheet and fill it in from memory, then check it against the answer key. Spaced practice over several short sessions works better than one long session the night before a test.

Spell it the way your teacher does

Some names have more than one form. Mitochondrion is one, mitochondria are many. Golgi apparatus, Golgi body and Golgi complex mean the same thing. ER is short for endoplasmic reticulum. Check your class notes and use the same spelling on the test.