CB.6 Prokaryotic cell structure. Comparison with eukaryotic cell structure. Biochemistry of bacterial cell walls including LPS, teichoic acids, proteins.

CB1.5 Comprehend the structure and function of key biochemical components of bacterial cells walls.

How is dental plaque an example of a biofilm?

• Dental plaque allows a microbial biofilm to form on the tooth surface which is full of different microorganisms: Bacteria, archaea, viruses, protozoa, fungi (e.g. Candida). 

• The biofilm forms a extracellular matrix to protect the microrganisms. The ECM is less rigid than matrices in eukaryotic tissues.  

• This film can be either above (supragingival) or below (subgingival) the gumline -->microbial biofilms on teeth digest the carbohydrates and cause caries.  

According to evolution which cell type has been around longer eukaryotes vs prokaryotes?

• Prokaryotes have been around for much longer than eukaryotes. Within prokaryotes archaea and bacteria are evolutionary very different classes of microorganisms 

• It is thought eukaryotes have arose through the internalisation of bacteria by archaea – so are a combination of the different groups.  

What is molecular phylogenetics?

• Molecular phylogenetics is the study of evolutionary relationships among organisms by analysing hereditary molecular differences, mostly in DNA, RNA, and protein sequences.

• —> How are organisms grouped: depends on how similar they are on a molecular level!  E.g. Ribosomal RNA genes are particularly useful to compare/contrast because they are present in all cells (prokaryotic and eukaryotic) --> Regions of variable sequence can distinguish between species.  

What is a phylogentic tree?

A branching diagram that shows the evolutionary relationships and history among various biological species or entities based on shared characteristics.

What are archaea? Where do you find them?

What diseases do archaea cause?

What is there cell structure and DNA structure like?

• Single-celled prokaryotic microorganisms that form an independent primary domain of life, separate from bacteria and eukaryotes 

• They are extremophiles – live in extreme environments  

• They are NOT pathogenic!

• Unique cell membranes – lipid bonds instead of ester bonds in bacteria.  

• DNA replication/transcription/translation is similar to eukaryotes. However, like prokaryotes lack membrane bound nucleus.  

Compare/contrast the structure of prokaryotes (dividing archaea and bacteria) with eukaroytes.

For the cytoplasm section - comment on the RNA and the organelles found.

What is the cell membrane structure for archaea, bacteria and eukaryotic cells?