LEC 7-
Cell Types in Microbiology
Dr Asma Umer Khayam
,Cells are the fundamental units of life, playing a
crucial role in all biological processes. In
microbiology, cells are classified into two main
types: Prokaryotic and Eukaryotic cells.
Understanding these cell types helps in studying
microbial physiology, pathogenesis, and the
development of medical treatments such as
antibiotics.
,1. Prokaryotic Cells
Definition: Prokaryotic cells are simple, unicellular organisms that lack a
membrane-bound nucleus and organelles. They include bacteria and
archaea.
A. Structure of Prokaryotic Cells
•Cell Wall: Provides shape and protection. Bacterial cell walls are made of
peptidoglycan, while archaea have different compositions.
•Cell Membrane: Regulates entry and exit of substances. Composed of a
phospholipid bilayer.
•Cytoplasm: Contains ribosomes, enzymes, and genetic material.
•Nucleoid: A region where circular DNA is found. It is not enclosed within a
membrane.
, •Ribosomes (70S): Smaller than eukaryotic ribosomes (80S),
involved in protein synthesis.
•Plasmids: Small, circular DNA molecules that provide antibiotic
resistance and other survival advantages.
•Flagella & Pili:
•Flagella: Aid in movement (e.g., Escherichia coli uses flagella for
motility).
•Pili: Help in attachment to surfaces and genetic material exchange
(conjugation).
•Endospores: Highly resistant structures formed by some bacteria
(e.g., Clostridium difficile) under harsh conditions.
Cell Types in Microbiology
Dr Asma Umer Khayam
,Cells are the fundamental units of life, playing a
crucial role in all biological processes. In
microbiology, cells are classified into two main
types: Prokaryotic and Eukaryotic cells.
Understanding these cell types helps in studying
microbial physiology, pathogenesis, and the
development of medical treatments such as
antibiotics.
,1. Prokaryotic Cells
Definition: Prokaryotic cells are simple, unicellular organisms that lack a
membrane-bound nucleus and organelles. They include bacteria and
archaea.
A. Structure of Prokaryotic Cells
•Cell Wall: Provides shape and protection. Bacterial cell walls are made of
peptidoglycan, while archaea have different compositions.
•Cell Membrane: Regulates entry and exit of substances. Composed of a
phospholipid bilayer.
•Cytoplasm: Contains ribosomes, enzymes, and genetic material.
•Nucleoid: A region where circular DNA is found. It is not enclosed within a
membrane.
, •Ribosomes (70S): Smaller than eukaryotic ribosomes (80S),
involved in protein synthesis.
•Plasmids: Small, circular DNA molecules that provide antibiotic
resistance and other survival advantages.
•Flagella & Pili:
•Flagella: Aid in movement (e.g., Escherichia coli uses flagella for
motility).
•Pili: Help in attachment to surfaces and genetic material exchange
(conjugation).
•Endospores: Highly resistant structures formed by some bacteria
(e.g., Clostridium difficile) under harsh conditions.
