kingdom monera Flashcards
what is kingdom monera?
1)bacterias are the sole members
2)they are present everywhere
3)first inhabitants of the earth
they can survive really harsh environments
what are the general characters of kingdom monera?
?
1) Monera (Monos - single) includes prokaryotes.
2) They are typically unicellular organisms (but one group is mycelial).
3) ds DNA with non-histone protein and no nuclear membrane called nucleoid/genophore/incipient nucleus/prochromosmes
4) Ribosomes and simple chromatophores are the only subcellular organelles in the cytoplasm. The ribosomes are the 70S.
5) Sap vacuoles do not occur. Instead, a gas vacuole may be present.
6) The predominant mode of nutrition is heterotrophic but some are autotrophic. autotrophic is photosynthesis or chemosynthetic and heterotrophy is symbiotic, parasitic or saprotrophic
7) The organisms are non-motile or move by beating of simple flagella or by gliding.
8)Flagella, if present, are composed of many intertwined chains of the protein flagellin. They are not enclosed by any membrane and grow at the tip.
Moneran cells are microscopic (1 to few microns in length).
9) Most organisms bear a rigid cell wall (peptidoglycan).
10) Reproduction is primarily asexual by binary fission or budding. exchange of genetic material occurs through conjugation-parasexual reproduction
11) It includes bacteria, actinomycetes, mycoplasma and cyanobacteria.
12) respiratory enzymes are found associated with the plasma membrane
explain the different shapes of monera?
1) spherical coccus
2) rod-shaped bacillus -most common
3) spiral spirillum
4)comma-shaped vibrium
explain respiration in bacteria?
1) aerobic respiration:
- O2present
- respiratory enzyme present
- release more energy
- bacterias that undergo aerobic respiration si called aerobes
2) anaerobic respiration:
- O2absent
- respiratory enzyme absent
- release less energy
- bacterias that undergo anaerobic respiration si called anaerobes
explain aerobes?
1) obligate aerobes
- die in the absence of O2
- requires O2 for survival
eg: bacillus subtilis
2) facultative aerobes
- survives in the absence and presence of O2
- eg: pseudomonas
explain anaerobes?
1) obligate aerobes
- die in the presence of O2
- requires absence O2 for survival
eg: clostridium botulicum
2) facultative aerobes
- survives in the absence and presence of O2
- eg: chlorobium
explain nutrition in bacteria.
they are divided into:
1) autotrophic: are able to synthesize their own food from inorganic substances, as green plants do. Their carbon is derived from carbon dioxide. The hydrogen needed to reduce carbon to organic form comes from sources such as atmospheric H2, H2S or NH3.
- chemosynthetic: chemicals
- photosynthesis: based on sun
2) heterotrophic: can not synthesize their own organic food. They are dependent on external organic materials and require at least one organic compound as a source of carbon for their growth and energy.
a) saprotrophic
b) symbiotic
c) parasitic
explain chemosynthetic nutrition?
depend on the oxidation of inorganic substances for nutrition.
- helps in recycling of nutrients like nitrogen ,phosphorus , iron and sulphur
1) nitrifying: - NH3 -> NO2
eg: Nitrosomonas , nitrococcus - NO2 ->NO3
eg: nitrobacteria , nitrocyctis
2) iron bacteria
- FE^2+ -> FE ^3+
eg: leptothrix,ferrobascilus
3)hydrogen bacteria
-H2-H20
eg;hydrogenmonas
4) sulphur bacteria
- H2S->S
eg: beggiatoa
- S -> H2SO4
eg: thiobacillus thioxidans
explain photoautotrophic nutrition?
-in bacteria, does not release oxygen thus called anoxygenic
- needs an electron (not from water)to convert co2 to glucose
-hydrogen is picked up by NAD+ to form NADH, NADH along with ATP is used to reduce CO2 to glucose
-splitting of water is not invovled
1)photolithograph:
a used inorganic sulphur compound as e- and H+ donors
based on pigment dived into :
-purple sulphur bacteria: uses bacteriopurpin(purple colour pigment)
eg: thiobascillus, thioprillium chromatium
-green sulphur bacteria:
- uses bacteriovirdin or bacteriochlorophyll( chlorobium chlorophyll)
-uses H2S as e- and H+ donors
eg;chlorobium
2)photoorganotroph: uses non-Sulpher aliphatic compounds as e- and H+ donors.
based on pigment:
- purple non-sulphur bacteria: uses bacteriopurpin
eg: rhodosprillium, rhodopseudomonas
-green non-sulphur bacteria: uses bacterioviridin or bacteriochlorophyll
eg: chloronema
explain saprotrophic nutrition.
- living bacteria obtain food from organic remains, e.g., animal excreta, fallen leaves, vegetables, etc.
- feeds on dead and decaying matter
- converts complex organic substances to a simple substances with help of digestive enzymes.
explain symbiotic relation.
- live in mutually beneficial association with other organisms. Eg., E.coli, rhizobium leguminosarum
- they are gram -ve
- rhizobium leguminosarumlives in the root nodules of legumnius plants.
explain parasitic nutrition
- obtains nourishment or special organic compounds required for growth from the host organism.
- if it causes disease in the host then its called pathogenic otherwise called non-pathogenic
give examples of bacterias involved in nitrogen fixation.
1) rizobium leguminsarum
2) azotobacter , beijerinckia, kelbsiella are aerobiac and free living
3) clostridum pasteurianum is anerobic
explain binary fission in bacterias .
during favourable conditions like optimum temperature, enough space, enough nutrients etc.
the cell undergoes amitosis or binary division.
it has 3 steps:
1)DNA division
- the dividing dna looks like greek letter theta thus called theta model
- suggested by cairn thus caled cairn’s theta model
2) mesosome division
3) cross wall formation
what do bacterias do during unfavourable conditions?
during unfavourable conditions, the bacteria form a perenating structure/organ for perenation.
explain endospore formation
- -endospore formation
- triggered during unfavourable conditions
- each bacteria forms an endospore
- can survive in extreme temperatures: -100 to 100 degrees celsius
-this resistance is due to the presence of calcium dipicolinic (ca-DPA)in the cortex
what are the different methods of sexual recombination/parasexual reproduction/ genetic reproduction?
1) transformation. by griffith(1938)
eg: ,diplococcus pneumoniae,streptococcus pneumonia
2) conjugation by ledberg& tatum(1946)
eg: E.coli
3) transduction : lederberg and ziner (1952)
eg: salmonella typhimurium
explain the characteristics of the s3 strain of streptococcus pneumonia?
1) s3 strain(s= smooth):
- cultured: smooth colonies
- mucous polysaccharide coat present
- virulent
- pathogenic
- causes pneumonia in the host
explain the characteristics of R2 strain of streptococcus pneumonia?
r2 strain(r= rough):
- cultured: rough colonies
- mucous polysaccharide coat absent
- avirulent
- not pathogenic
explain the griffith’s experiment?
host: mice
bacteria: streptococcus pneumonia
1) live s3 strain -mice - death
2) live r2 strain - mice - alive
3) heat-killed S3 strain - mice - alive
4) live R2 strain + heat-killed S3-mice - death
- on extraction of blood from the mice in the 4 th step, living S3 strain was found
conclusion: some substance transferred from heat-killed S3 strain to R2 strain that turned R 2 strain to S 3 strain.
explain The Avery–MacLeod–McCarty experiment.
- -in vitro / glass
- extracted protein RNA & DNA from heat killed S3
1) added the protein to a test tube with R2 strain-no change .
2) added the RNA to a test tube with R2 strain-no change
3) added the DNA to a test tube with R2 strain- R2 transformed into S2
4) added the DNA and Dnnase(dna digesting enzyme) to a test tube with R2 strain-no change
therefore DNA is the material that transformed R2 to S3
what is transformation?
Bacterial transformation is a process of horizontal gene transfer by which some bacteria take up foreign genetic material (naked DNA) from the environment. … The prerequisite for bacteria to undergo transformation is its ability to take up free, extracellular genetic material. Such bacteria are termed as competent cells.
explain The Hershey-Chase Experiments ?
-by Alfred Hershey and Martha Chase
-(A) bacteriophage- DNA contain phosphorous
-(B) bacteriophage -protein contains
sulphur((cyestine.methionine)
The experiment began with the culturing of bacteriophages in two types of medium. One set of bacteriophage (A) was cultured in a medium of radioactive phosphorus whereas another set (B) was cultured in a medium of radioactive sulfur. They observed that the first set of bacteriophage (A) consisted of radioactive DNA but not radioactive proteins. This is because DNA is a phosphorus-based compound while protein is not. The latter set of bacteriophage (B) consisted of radioactive protein but not radioactive DNA.
The host for infection was E.coli bacteria. The bacterophage were allowed to infect bacteria by removing the viral coats through a number of blending and centrifugation.
Observation: E.coli bacteria which were infected by radioactive DNA bacteriophage (A) were radioactive but the ones that were infected by radioactive protein bacteriophage (B) were non-radioactive.
Conclusion: Resultant radioactive and non-radioactive bacteria infer that the bacteriophage that had radioactive DNA transferred their DNA to the bacteria but bacteriophage that had radioactive protein didn’t get transferred to the bacteria. Hence, DNA is the genetic material and not the protein.
explain reproduction in bacteria during favourable condition?
repeated binary fission leading the to formation of large population, such rapid rate is rarely achievd.
