• 14 parts
  • Checked October 2026

Blank Bacterial Cell Wall Diagram

Three kinds of bacterial wall cut through and drawn as patterns, with every name left off.

Blank Bacterial Cell Wall Diagram

Name Date

Blank diagram

1 2 3 4 5 6 7 8 9 10 11 12 13 14
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Write the name of each numbered part.Answer key

  1. Peptidoglycan
  2. Teichoic acid
  3. Lipoteichoic acid
  4. Plasma membrane
  5. Outer membrane
  6. Lipopolysaccharide
  7. Porin
  8. Peptidoglycan
  9. Periplasm
  10. Plasma membrane
  11. Mycolic acids
  12. Arabinogalactan
  13. Peptidoglycan
  14. Plasma membrane

Drawn for this site on 2026-10-01 from plain geometry. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

Next step Read every name on the labeled walls

All 14 parts on the diagram

Show the list

Gram-positive wall 4

  1. Peptidoglycan A thick mesh of sugar chains and short peptides. It makes up most of this wall.
  2. Teichoic acid A long chain bound to the peptidoglycan. It runs through the wall and out past the surface.
  3. Lipoteichoic acid A teichoic acid held in the plasma membrane by a lipid. It crosses the whole wall.
  4. Plasma membrane The membrane under the wall. It encloses the cytoplasm.

Gram-negative wall 6

  1. Outer membrane A second membrane outside the thin peptidoglycan layer. Chains of lipopolysaccharide stand on it.
  2. Lipopolysaccharide Chains of sugars on a lipid anchor in the outer membrane. The lipid part is called lipid A, or endotoxin.
  3. Porin A protein channel through the outer membrane. Small molecules pass through it.
  4. Peptidoglycan Only a thin layer here. It lies in the periplasm between the two membranes.
  5. Periplasm The gel-filled space between the outer membrane and the plasma membrane.
  6. Plasma membrane The inner of the two membranes. It encloses the cytoplasm.

Acid-fast wall 4

  1. Mycolic acids Long fatty acids packed into a waxy outer layer. They make up most of this wall.
  2. Arabinogalactan Branched chains of two sugars. They link the peptidoglycan below to the mycolic acids above.
  3. Peptidoglycan A thin inner layer. The arabinogalactan is linked to it.
  4. Plasma membrane The membrane under the wall. It encloses the cytoplasm.

How this list was compiled: Every part was checked on 2026-10-01 and kept only where two independent sources name it. (1) Gary Kaiser, Microbiology, sections 2.3A The Gram-Positive Cell Wall, 2.3B The Gram-Negative Cell Wall and 2.3C The Acid-Fast Cell Wall, an open college textbook, https://bio.libretexts.org/Bookshelves/Microbiology/Microbiology_(Kaiser)/Unit_1%3A_Introduction_to_Microbiology_and_Prokaryotic_Cell_Anatomy/2%3A_The_Prokaryotic_Cell_-_Bacteria/2.3%3A_The_Peptidoglycan_Cell_Wall/2.3A%3A_The_Gram-Positive_Cell_Wall . (2) Wikipedia, text only: Gram-positive bacteria, https://en.wikipedia.org/wiki/Gram-positive_bacteria ; Gram-negative bacteria; Bacterial cell structure; Teichoic acid; Lipopolysaccharide; Peptidoglycan; Mycobacterium; Mycolic acid. Licence: own work

The drawing: Drawn for this site on 2026-10-01 from plain geometry; nothing traced. Licence: own work

How it works

This blank bacterial cell wall diagram stacks three slices: Gram-positive at the top, Gram-negative in the middle, acid-fast at the bottom. In each, the outside of the cell is up. Fourteen names go on.

Read the full guide

The fourteen names, wall by wall

Gram-positive: peptidoglycan, teichoic acid, lipoteichoic acid, plasma membrane. Gram-negative: outer membrane, lipopolysaccharide, porin, peptidoglycan, periplasm, plasma membrane. Acid-fast: mycolic acids, arabinogalactan, peptidoglycan, plasma membrane.

Which pattern takes which name

Brickwork is peptidoglycan: a thick slab at the top, a thin strip in the other two. A double row of round heads is a membrane: the lowest in each drawing is the plasma membrane, and the upper one of the middle drawing the outer membrane. A wavy chain that ends in the brickwork is a teichoic acid; one that goes down to the membrane is a lipoteichoic acid. Bead strings are lipopolysaccharide, barrels porins, and the clear space between the two membranes periplasm. Forked lines are arabinogalactan and the tall upright lines mycolic acids.

  • The speckled strip under each plasma membrane is cytoplasm. It takes no name.
  • The sheet has no label lines. Each name goes on its own layer, or at the end of a line you rule to the margin.
  • Murein is another name for peptidoglycan, and cytoplasmic membrane for the plasma membrane. A course may use either.

Questions and answers

What color do Gram-positive and Gram-negative bacteria stain?

Gram-positive cells keep the crystal violet stain and look purple under the microscope. Gram-negative cells lose it at the decolorizing step, take up the counterstain and look red or pink.

What is peptidoglycan made of?

Sugars and amino acids. Chains of two alternating sugars, N-acetylglucosamine and N-acetylmuramic acid, are cross-linked through short peptides of three to five amino acids into a mesh. The brickwork on the sheet stands for that mesh.

What does acid-fast mean?

That the stained cell resists decolorization with an acid-alcohol mixture: it keeps the first dye, carbol fuchsin, and appears red. A wall with a waxy outer layer rich in mycolic acids resists acids in this way.

Do all bacteria have peptidoglycan in the cell wall?

Nearly all. The mycoplasmas are an exception: they lack the peptidoglycan layer. Where there is one, it lies immediately outside the cell membrane.

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