|What is the cell wall made of?
|Question Date: 2015-02-02|
The composition of the cell wall varies from that
organism that has it. Thus it is different when
considering a fungus, a bacterium, or a plant. In
bacteria, the cell wall is made of a substance
called “peptidoglycan.” The “peptide” part
of the substance is from short chains of amino
acids called peptides. Amino acids are a major
building block of life and are what make up
proteins. The “glycan” part is long chains of
sugars which along with the peptides make up the
mesh of the cell wall.
In plants, the cell wall is mostly made up of
various sugars such as cellulose. These sugars are
connected in a way such that your body can’t
digest them and are also known as “dietary fiber”.
Fungi have cell walls made of sugars too, but
different ones than you would normally find in a
plant. All of these cell walls are made of very
different molecules than the cell membrane which
is mostly made up of lipids (fats are a type of
A variety of organisms have cell walls. Plant
cell walls are made of mostly of cellulose,
hemicellulose, and pectin. There compounds make a
rigid cell wall that gives the plant structure to
Fungi and other organisms like diatoms have cell
walls made of different compounds such as chitin
Animal cells, on the other hand, don't have cell
walls and as a result don't have very rigid
Cell walls are usually found in plants, fungi, and
various prokaryotes (bacteria, etc.. It is a
tough, yet flexible structure that provides
structure, protection, and permeability to the
cells. Also, it is used to maintain the pressure
inside the cells and prevent the cells from
over-expansion. The material which makes up cell
walls differs in various cell types. Bacterial
cell walls are made up of peptidoglycan, a
material made from 2 different polysaccharides -
N-acetylmuramic acid (NAM) and N-acetylglucosamine
Cell walls of fungi are composed of chitin,
which made up of many N-acetylglucosamines (NAG).
A plant cell wall is composed of cellulose, a
complex sugar. Algae and different members of
archaea have cell walls composed of different
materials. Although the cell walls in all of these
organisms are created from different materials,
they serve the same function.
That depends on the cell. Plant cell walls are
made out of cellulose. Fungal cell walls are made
of chitin, the same stuff that insect skeletons
are made of. Bacterial cell walls are made out of
peptidoglycan, which is a mixed protein-sugar
material unique to bacteria. Animal cells don't
have cell walls.
Very interesting question. In plants, cell
walls are made up of a material called
cellulose. It is an extremely tough
structural molecule that is very hard to digest.
In fact, there are very few animals that can
actually eat and digest cellulose. When you read
about foods that are high in fiber, they are
referring to the tough cellulose in the plant
walls. Fiber is good for you but you don't really
digest much of it.
The answer to your question depends on which
kind of organism we are talking about. The main
kinds of organisms that have cell walls are
plants, fungi, and certain prokaryotes (bacterial
In plants, cell walls are mainly comprised
of complex polysaccharides (sugar-based polymers)
molecules such as cellulose, hemicellulose, and
pectin. In between these polysaccharides are
lignin, a complex biopolymer made of alcohols that
contributes to the structural integrity of the
cell wall by crosslinking with the different
polysaccharides. Plant cell walls also have
various proteins and enzymes embedded in the the
wall and as surface accessories which provide
various support and functionality in the cell
Fungal cell walls contain different
polysaccharides from plants: chitin, glucans, and
mannans. They also contain various proteins.
However, the composition of fungal cell walls can
vary widely between different species.
Bacterial cell walls fall under two main
categories: gram positive and gram negative.
Gram positive walls are thick, and have many
layers of peptidoglycans (protein+sugar) and
teichoic acids (polysaccharides). Gram negative
walls on the other hand are thin, only have a few
peptidoglycans, and are surrounded by a second
lipid (fats) membrane consisting of
lipopolysaccharides and lipoproteins.
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