Introduction to Prokaryotes

Prokaryotic cells

Cells that do not have a nucleus.

Three domains of classification

Bacteria

Eukarya

Archaea

Methanogens, halophiles, and thermophiles

Gram-positive and gram-negative bacteria

Animals

The chromosomal DNA of prokaryotic cells is a condensed structure in the cell that does not contain any sort of membrane surrounding it. The chromosomal DNA does not replicate at the same rate of the plasmid DNA. This DNA is responsible for the replication of the prokaryotic ell and the generation of ribosomes

Extrachromosomal DNA or plasmid DNA is in the form of circle-like DNA that is present outside of the boundary of the chromosomal DNA. This DNA is not responsible for replication of the cell but rather its properties such as resistance against certain antibiotics in bacteria

Bacteria

Gram negative bacteria

These are bacteria that have a thin peptidoglycan layer that is instead protected by an outer membrane. This outer membrane allows for antibiotics such as penicillin to not have any effect on this bacteria as penicillin specifically affects gram-negative bacteria. Gram-negative bacteria also contain a lipopolysaccharide layer which is pro-inflammatory. This therefore allows for another line of defence

Gram-positive bacteria

Gram-positive bacteria have a thick peptidoglycan wall which is able to protect the cell. Unlike gram-negative bacteria they also have teichoic acid channels which allow for the transfer of molecules and solutes in and out of the cell. In this case, penicillin is able to attack and cause for the break down of this bacteria as it affects the cross-linking proteins that assist in the structure

Transcription is the process of converting DNA to RNA and translation is the process of converting an RNA to protein

The ribosomes found in bacteria (prokaryotic cells) are smaller than the ones in eukaryotic cells (70S compared to 80S). Here, S is the unit in which size is calculated (Svedberg units).

No type of bacteria contain a cytoskeleton

These bacteria, in a gram stain, stain purple.

These bacteria, in a gram stain, stain pink.

Bactericidal antibiotics, in their response, kill off the bacteria

Bacteriostatic antibiotics on the other hand do not kill the bacteria, but put in measures to stop their proliferation, or reproduction