Procaryotes Eucaryotesy y

size, membranous organelles

* same basic chemical composition* same genetic codesa e ge et c code* same basic metabolic processes

Plasma membrane(cell membrane, cytoplasmic membrane)

FunctionFunction• Semi-permeable barrier• Transport• Proton gradient (energy

)processes)• Receptors• Cell division• BiosynthesisBiosynthesis

Constituents25% li id ( h h li id )

Examples of their i t• 25% lipids (phospholipids)

• 75% proteins (transport, receptors, energy processes, etc.

importance• Thermophilic micro-

organisms contain saturated fatty acids

• 5-10 mm• “Floating mosaic”• Bacteria lack sterols but

contain hopanoids

• Psychrophilic micro-organisms contain unsaturated fatty acids

• Detergents act on the l bcontain hopanoids plasma membrane

Ph h li idPhospholipids

Ester bond = eukaryotes and eubacteria

Ether bond = archaebacteria

Phospholipids unsaturated fatty acidsPhospholipids unsaturated fatty acids(Psychrophilic micro-organisms)

Plasma membrane of thermophilic i imicro-organisms

G+ cell walls in eubacteriaG cell walls in eubacteria

FunctionFunction• Mechanical, chemical and

physical protection• Protection against osmotic

l ilysis

ConstituentsConstituents• Peptidoglycan (a polymer

consisting of n-acetyl glucosamine, n-acetyl muraminic acid andmuraminic acid and peptides, 20-80 nm)

• Periplasmic space• Teichoic acid

Examples of its importance• Gram staining• Turgor

• S-layer• Capsule

Turgor• Lysozymes• Food preservatives

Cell envelopes of archaebacteria

Fimbriae and flagella

fimbriae (s., fimbria)short, thin, hairlike, proteinaceous

sex pili (s., pilus)similar to fimbriae proteinaceous

appendagesup to 1,000/cell

mediate attachment to

except longer, thicker, and less numerous (1-10/cell)required for matingsurfaces required for mating

flagellum rotates

Proteus vulgaris

like a propeller in general, counterclockwise rotation causesrotation causes forward motion (run)

The genetic materialThe genetic material

D ib l i• Deoxyribonucleic acid (DNA)

• Nucleoid =• Nucleoid = prokaryotes

• Nucleus = eukaryotes

• Haploid/diploid(chromosomes)

• PlasmidsP i• Proviruses

Membrane-bound organelles that perform specific functions