cell wall

Presentation on

BACTERIAL CELL WALL, FUNGAL CELL WALL & PLANT CELL WALL

in Molecular Biology & Genomics

Presented by-Subash ChowdhuryRoll : 86422nd BatchDepartment of Pharmacy, USTC

Bacteria (singular: bacterium) constitute a large domain of prokaryotic microorganisms.

The study of bacteria is known as bacteriology, a branch of microbiology.

Bacteria was first discovered by Antony van Leeuwenhoek in 1970s.

Bacteria

Fig:- structure of bacteria

Different shapes of Bacteria

Bacterial cell wall is a rigid structure which gives the shape of the cell.

Unique to bacteria. Protecting cell from osmotic lysis.

Bacterial cell wall

Cell Wall

Cytoplasm

Cell membrane

Peptido-glycan Polymer (amino acids + sugars)

Sugars; NAG & NAM N-acetylglucosamine

(G) N-acetymuramic acid

(M)

Structure and Chemical composition of Bacterial cell wall

Structure of peptidoglycan

Structure of peptidoglycan

According to the position of peptidoglycan layer in the cell wall bacteria are classified into two types.

Gram positive bacteriaGram negative bacteria

Types of bacterial cell wall

In gram positive bacteria The thick peptidoglycan layer in the cell wall that encases their cell membrane

In Gram negative bacteria the thin peptidoglycan layer of their cell wall is sandwiched between an inner cell membrane and a bacterial outer membrane.

Comparison between the Gram(+) & Gram(-) Cell

wall

Gram staining

Protect cells against osmotic shock (most important) and physical damage.

Regulation of substance transport into and out of cells.

Contain genome. Contain supplemental genetic information such as

resistance to antibiotics, production of toxins and tolerance to toxic environment.

Take part in protein synthesis. Movement of cells. Mineral storage of cells.

Function of bacterial cell wall

Fungi are eukaryotes Nearly all multicellular

(yeasts are unicellular) Spore-bearing protists that

lack chlorophyll. Two types:- 1. Yeasts 2. Molds (filamentous

and multicellular)

Fungi

The cell wall is made up of:1) chitin (polymers of acetylated amino sugar N-

acetyl-glucosamine)2) glucan3) Proteins

Glucan and chitin are components of the primary wall.

Proteins are components of the secondary wall.Other components include chitosan, melanins and

lipids. Enzymes include cellulase which acts on cellulose

of plants.

Fungal cell wall

Basic component of fungal cell wall

Secondary wall

Primary wall

Chained polymer β(1-4) N-acetyl-glucosamine. Microfibril Microfibrils can be of various shapes:

in yeast: short and thick in hyphal wall: long and interwoven

Septa

Chitin

Glucans

Protects against osmotic lysis Acts as a molecular sieve Contains pigments for protection Binding site for enzymes

The outermost surface of the cell wall 1) provides a medium between the cell and the

environment 2) a site where antigen and agglutinin gets attached to

the substrate, host and other cells.

Function of fungal cell wall

Cell wall is a rigid & rough. Situated outside the cell membrane. The cell wall was discovered by Robert Hooke in

1665.

Plant Cell Wall

Major Regions of the Cell Wall

Components of the cell wall

Components of the cell wall

determining cell shape support and mechanical strength prevents the cell membrane from bursting controls cell growth and cell volume physical barrier carbohydrate storage

Functions of the Cell Wall

Thank you