total biomass of earth is
35x greater than the total biomass of all animals
bacterias size range is
1-10 um length and 0.2-2 in diameter
the three types of bacteria shapes
1- rods aka bacillus as: salmonella
2- spherical aka ovoid aka coccus as: micrococcus
3- spiral/ wavy aka spirillus as: spiroplasma
bacteria lack
membrane bounded organelle bc they r prokaryotes as: er, mitochondria , nucleas, lysosome, chloroplast
main components of the bacteria
- cytoplasm
- nucleoid contains the dna
- plasma membrane
- ribosome
the function of cytoplasm
- dense and contains ribomes
-storage granules as glycogen, lipids, phosphate - metabolic enzymes
- ribosomes have 2 subunits large and small contains proteins and rna
function of the nucliod
- instead of the nucleas
- contains 3000-6000 genes from cytoplasm
- contains single circular double helix dna
- histone don’t need to be utilised bc the dna is supercoiled
a small circular double stranded dna molecule w selective benefits genes which increases the virulence
plasmid
capsule is a
thick gelatinouse structure composed of polysacrides that extend 10 micrometers and they increase the virulence.
- defines against hosts immune system
- prevent binding of antibodies to antigens
- prevents phagocytosis of bacteria
allows motility for the bacteria and acts as propeller
flagella and is composed of: hook, filament, basal granuel anchored in the cell wall and cell membrane
pilli is
- hair like structure
- increases virulence by enhancing the ability to bind to body tissues
- allows clumping of bacteria
- used to transfer dna in conjunction
- 2 types: ordinary which is adherence of bacteria to the host cells and sex pills which is attachment of donor an recipient in bacterial conjunction
true or false: gram negative is more pathogenic and resist antibiotic
true bc the outer membrane is more antigenic and contributes to its pathogenicity.
the gaps between the outer ( periplasmic spaces ) and inner membrane are filled with
enzymes and transport protein for biochemical reactions
staining
+ve: purple also stained by pink but only purple will be visible
-ve: stains pink
endospores
- bacteria enters high resistant dormant stage
- unfavored conditions as lack of nutrients
- after dna replication, the spore septum will form around the newly synthesis dna and section of the cytoplasm
- layer of plasma membrane will cover it with peptiglycan in between
- tough spore coat will form around it causing dehydration
- now the bacteria can resist extreme conditions such as: radiation, antibiotics, dehydration.
- favorable conditions will reactive it and they will grow and multiply,
bacteria reproduce by
-binary fission asexual reproduction
- origin of replication will open allowing dna replication to start, cells elongate more towards end as the dna will be copied, septum will form down the middle, two cells will be produced.
- the multiply every 20 minutes
- bacteria can produce 250,000 individuals every 6 hours
true or false: fusion of gametes don’t occur in bacteria
true, they undergo bacterias exchange of dna instead in three methods:
- transformation: fragments of dna are taken after disruption of other cell.
- conjucntion: two cells exchange dna but sex pills
- transduction: genes carried from one cell to another by virus aka bacteriophage. Also known as: horizontal gene transfer ( sideways to unrelated organisms ) while vertical is direct gene transfer
the process of transformation can be done
- naturally by changing their genome rapidly to adapt to new environment
-artifically by placing plasmids inside so they can produce useful products as insulin
the process of conduction is when
- direct contact is needed
1- donor cells produce conjunctions pillus and attaches it to recipient cell
2- donor plasmid is nick and single strand of dna will be attached to recipient cell
3- both cells will synthesise a complementary strand to produce double strand circular plasmid
transduction
- viral transfer of genetic material
- some viruses can infect the bacteria : bacteriphage
- viruse will utilise the bacteria replicative proteins and produce copies of itself
- new viruses will be produced, fragments of bacterial dna can be incorporate.
- when phage infects new bacteria, dna from the first bacteria can integrate into the new bacterias chornosme.
