A bacterium has a thick, tough layer outside its cell wall…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A bacterium has a thick, tough layer outside its cell wall.
- Name the three layers of its cell envelope, from the outside in.
- What is the tough outer layer called?
- What would a looser outer layer be called?
Need a reminder? The key ideaShow
Prokaryotes: bacteria, blue-green algae, mycoplasma and PPLO. Cell envelope: glycocalyx (slime layer or capsule), cell wall, plasma membrane. Naked DNA in a nucleoid, plus plasmids. Mesosomes are infoldings of the membrane. Flagellum: filament, hook, basal body; pili and fimbriae do not move the cell. 70S ribosomes (50S and 30S) and polysomes; inclusion bodies have no membrane.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. (a) Glycocalyx, cell wall, plasma membrane.
Step 2. (b) A thick, tough glycocalyx is a capsule.
Step 3. (c) A loose sheath is a slime layer.
Answer: (a) glycocalyx, cell wall, plasma membrane; (b) capsule; (c) slime layer.
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