Prokaryotes
Content:
Structure of prokaryotes……………………………………………………………………………………(2 – 5)
Cell wall ( gram positive and negative)……………………………………………………………….(5 – 9)
Importance of prokaryotes………………………………………………………………………………..(9 – 12)
1
, Prokaryote structure
Overview of prokaryotes (bacteria and archaea). Structural features of prokaryotic cells
Key points:
• Prokaryotes are single-celled organisms belonging to the domains Bacteria and
Archaea.
• Prokaryotic cells are much smaller than eukaryotic cells, have no nucleus, and lack
organelles.
• All prokaryotic cells are encased by a cell wall. Many also have a capsule or slime
layer made of polysaccharide.
• Prokaryotes often have appendages (protrusions) on their surface. Flagella and
some pili are used for locomotion, fimbriae help the cell stick to a surface, and sex
pili are used for DNA exchange.
• Most prokaryotic cells have a single circular chromosome. They may also have
smaller pieces of circular DNA called plasmids.
Prokaryotes are microscopic organisms belonging to the domains Bacteria and
Archaea, which are two out of the three major domains of life. (Eukarya, the third,
contains all eukaryotes, including animals, plants, and fungi.) Bacteria and archaea are
single-celled, while most eukaryotes are multicellular.
Fossils show that prokaryotes were already here on Earth 3.53.53, point, 5 billion years
ago, and scientists think that prokaryotic ancestors gave rise to all of the life forms
present on Earth today^{2,3}2,3start superscript, 2, comma, 3, end superscript
2
Content:
Structure of prokaryotes……………………………………………………………………………………(2 – 5)
Cell wall ( gram positive and negative)……………………………………………………………….(5 – 9)
Importance of prokaryotes………………………………………………………………………………..(9 – 12)
1
, Prokaryote structure
Overview of prokaryotes (bacteria and archaea). Structural features of prokaryotic cells
Key points:
• Prokaryotes are single-celled organisms belonging to the domains Bacteria and
Archaea.
• Prokaryotic cells are much smaller than eukaryotic cells, have no nucleus, and lack
organelles.
• All prokaryotic cells are encased by a cell wall. Many also have a capsule or slime
layer made of polysaccharide.
• Prokaryotes often have appendages (protrusions) on their surface. Flagella and
some pili are used for locomotion, fimbriae help the cell stick to a surface, and sex
pili are used for DNA exchange.
• Most prokaryotic cells have a single circular chromosome. They may also have
smaller pieces of circular DNA called plasmids.
Prokaryotes are microscopic organisms belonging to the domains Bacteria and
Archaea, which are two out of the three major domains of life. (Eukarya, the third,
contains all eukaryotes, including animals, plants, and fungi.) Bacteria and archaea are
single-celled, while most eukaryotes are multicellular.
Fossils show that prokaryotes were already here on Earth 3.53.53, point, 5 billion years
ago, and scientists think that prokaryotic ancestors gave rise to all of the life forms
present on Earth today^{2,3}2,3start superscript, 2, comma, 3, end superscript
2
