KINGDOM-MONERA · 2020. 8. 24. · KINGDOM-MONERA (prokaryotes) Main characteristic of prokaryotes 1. Glycocalyx (Capsule or Slime layer) - —Loose and thin layer is called slime

KINGDOM-MONERA (prokaryotes)

Main characteristic of prokaryotes

1. Glycocalyx (Capsule or Slime layer) - —Loose and thin layer is called slime layer and thick and tough layer is called capsule. Formation of Glycocalyx is done

by cell membrane. —Capsule is made up of polysaccharides and polypeptides while slime layer is made up of mainly polysaccharides.

—Glycocalyx protects the bacteria from W.B.C. and also helps in colony formation

2. Cell wallCell wall of prokaryotes is made up of peptidoglycan (peptide(amino acid) + glycan(polysaccharide)).

3.Cell membrane—Like eukaryotes the cell membrane of prokaryotes is made up of lipoprotein [lipid + protein].—The cell membrane invaginate and form structure like mesosomes and chromatophores that perform function like respiration and photosynthesis respectively.

—The space between cell wall and cell membrane is known as periplasmic space.This space, is analogous to lysosome because in this space the digestion of complex substance is done.

4.Cytoplasm— In bacterial cytoplasm membrane bound cell organelles viz. Mitochondria, Chloroplast, E.R., Lysosome, Golgi body, micro bodies etc. are absent.—Bacterial cytoplasm shows no streaming or cyclosis.

(A). Storage granules/Inclusion bodies -—Reserve material in prokaryotic cells are stored in the cytoplasm in the form of inclusion bodies.—These are not bounded by any membrane system and lie free in the cytoplasm.

(B). RIBOSOMES- membrane less cell organelle.—only organelle founds in both prokaryotic and eukaryotic cell.—ribosomes perform function of protein synthesis— in prokaryotes 70s type of ribosomes are found

(C). Gas vacuoles - membrane less structure that provide buoyancy.

(D).Nucleoid- In Prokaryotic cell, the nucleus is indistinct. The nucleus of prokaryotes is also known as incipient nucleus, genophore, nucleoid or fibrillar nucleus. —Nuclear membrane is absent around nucleus. —It also lacks nucleolus.—Prokaryotes also lack the true chromosome. Instead of it, a false

chromosome is present, which is made up of ds circular naked DNA + Non histone protein like polyamines.—This false chromosome coils and forms the chromosomal region, which is known as nucleoid.

(E).Plasmid - Beside the main DNA another small and ds-circular DNA is also present in bacterial cell, which is called Plasmid.—It is also known as extra chromosomal or extranuclear genetic material.

5. Flagella- flagella is a modification of cell wall.— it help in motility6. Pili- Bacterial cell wall is covered by numerous hair like structures called pili. Pili are smaller than the flagella. — pili play role in attachment

Prokaryotes Eukaryote Simple cell Complex cell

primitive cell Advanced cell

Smaller cell Larger cell

Always found in unicellular organisms

Found in both unicellular and multicellular organisms

Nuclear membrane absent

Present

Nucleolus absent Present

Double stranded circular DNA found

Double stranded linear DNA found

Histone protein absent

Present

True chromosome absent

Present

True nucleus absentNucleoid/xenophobia/ incipient nucleus found

True nucleus present

Glycoclayx present Absent

Cell wall is made up of peptidoglycan

Peptidoglycan absent

Cholesterol absent in cell membrane

Present

Mesosomes present Mitochondria present

Chromatophores present

Chloroplast present

70s ribosomes present 70s and 80s ribosomes present

Inclusion bodies present

Absent

Gas vacuoles present

Absent

Plasmid present Absent

Cytoplasmic movement’s absent

Present

Prokaryotes Eukaryote

Examples of Prokaryotes(1) Eubacteria (True bacteria)(2) Mycoplasma(3) blue green Algae(4) Archaebacteria

Pili present Absent

Sexual reproduction absent

Present

Mitosis meiosis absent

Present

Prokaryotes Eukaryote