《微生物学》课程教学课件（PPT讲稿）Chapter 1 The structure and function of prokaryotes

Chapter 1 The structure and function of prokaryotes EUKARYOTES PROKARYOTES BACTERIA ARCHAEA

Chapter 1 The structure and function of prokaryotes EUKARYOTES PROKARYOTES BACTERIA ARCHAEA

1.Differences between prokaryotes/eukaryotes 2.Shape and arrangement 3. Procaryoic cell organization

1.Differences between prokaryotes/eukaryotes 2.Shape and arrangement 3.Procaryoic cell organization

Prokaryotes(Bacteria) o Eubacter rue bacteria human pathogens clinical or environmental one kingdom A achaea Environmental organisms second kingdom

Prokaryotes (Bacteria) • Eubacter "True" bacteria – human pathogens – clinical or environmental – one kingdom • Archaea – Environmental organisms – second kingdom

Eukaryotes Other cell-based life e.g. ants animals fungl

Eukaryotes • Other cell-based life e.g. – plants – animals – fungi

Differences between prokaryotesleukaryotes 1. The prokaryotic cell, in contrast to the eukaryotic cell, is not compartmentalized Nuclear membranes, mitochondria, endoplasmic reticulum, Golgi body, phagosomes and lysosomes are not present 2. Prokaryotes generally possess only a single circular chromosome, Since there is no nuclear membrane. the chromosome is bound to a specific site on the cell membrane the mesosome 3. Prokaryotic ribosomes are 70S (S stands for Svedberg unit, a measure of size), whereas eukaryotic ribosomes are larger (80S) Prokaryotic ribosomal subunits are 30S and 50S (eukaryotic are larger). The 30S ribosome has 16S RNA, whilst the 50S ribosome contains 23S and 5s RNA, Ribosomal rNa is larger in eukaryotes(e.g 18S versus 16S rRNA) 4. Bacterial membranes generally do not contain sterols( F)e.g cholesterol

1. The prokaryotic cell, in contrast to the eukaryotic cell, is not compartmentalized. Nuclear membranes, mitochondria, endoplasmic reticulum, Golgi body, phagosomes and lysosomes are not present. 2. Prokaryotes generally possess only a single circular chromosome. Since there is no nuclear membrane, the chromosome is bound to a specific site on the cell membrane - the mesosome. 3. Prokaryotic ribosomes are 70S (S stands for Svedberg unit, a measure of size), whereas eukaryotic ribosomes are larger (80S). Prokaryotic ribosomal subunits are 30S and 50S (eukaryotic are larger). The 30S ribosome has 16S RNA, whilst the 50S ribosome contains 23S and 5S RNA. Ribosomal RNA is larger in eukaryotes (e.g. 18S versus 16S rRNA). 4. Bacterial membranes generally do not contain sterols (甾醇)(e.g. cholesterol). Differences between prokaryotes/eukaryotes

Prokaryotic Cell(versus Eukaryotic Cell) Not compartmentalized Cell membranes lack sterols(e.g. cholesterol) Single circular chromosome Ribosomal are zos with subunits 30S (16SrRNA) 50s (5s 23SrRNA)

Prokaryotic Cell (versus Eukaryotic Cell) • Not compartmentalized • Cell membranes lack sterols (e.g. cholesterol) • Single circular chromosome • Ribosomal are 70S with – subunits 30S (16S rRNA) – 50S (5S & 23S rRNA)

Bacteria versus Archaebacteria ● Eubacteria peptidoglycan(murein muramic acid Archaebacteria pseudomurein no muramic acid

Bacteria versus Archaebacteria • Eubacteria – peptidoglycan (murein) – muramic acid • Archaebacteria – pseudomurein – no muramic acid

Bacteria versus Archaebacteria 16S TRNA sequence very different

Bacteria versus Archaebacteria • 16S rRNA –sequence very different

An overiew of procaryotic cell structre 1. size width× length E colic( average):1.1-1.5μm×2.0-6.0μm The smallest: Nanobacteria:0.05-02u m monsteous microbe: >10-50u m

An overiew of procaryotic cell structre 1.size:width×length E.coli(average): 1.1-1.5m × 2.0-6.0  m ? The smallest: Nanobacteria: 0.05-0.2 m ? monsteous microbe: >10-50 m

2. Shape and arrangement Coccus or Cocci R Spirillum or spirilla Spirochete Budding and appendaged coding and appendaged t Filamentous

Coccus or Cocci Rod Spirillum or Spirilla Spirochete Budding and appendaged Filamentous 2.Shape and arrangement