kingdom monera Flashcards
prokaryotes
they are either non-cellular, unicellular or filamentous. their cells do not contain true nucleus.
define bacteria and it’s classes
bacteria are the smallest and simplest organisms which have structure. they’re found everywhere in soil, water and air. they do not have chlorophyll and are even present in the respiratory and digestive tracks.
eubacteria :: it is a large bacteria and they are also called true bacteria.
archaebacteria :: it is a small bacteria and they are also called ancient bacteria.
types of bacteria
cocci :: they’re spherical in shape.
micrococcus : they’re single and aren’t arranged in groups (o)
diplococci : found in groups of two (oo)
streptococci : they’re arranged in chain like manner (oooo)
staphylococci : they’re present in groups // bundles
baccili :: they’re rod like in shape
microbacillius : they’re single and aren’t arranged in groups (-)
diplobacili : they’re found in groups of two (–)
streptobacilli : they’re arranged in a chain like manner
(—-)
staphylobacilli : they’re present in groups // bundles
spirilli : they’re spiral // cork-screw shaped and are never found in groups
vibrio : they’re comma shaped and also not found in groups ( , )
structure of bacteria (describe flagella, pilli.etc. )
flagella : flagella are thin hair structures which arise from basal body and help in locomotion.
pilli : they’re hollow, filament like structures. they don’t help in locomotion but help in conjugation process of reproduction
capsule : it is an additional protective layer around cell wall. it is composed of polysaccherides and proteins.
cell wall : it is present around the bacterial cell and is composed of amino acids, sugar and chitin. in the cell wall, a compound is present known as peptidoglycan ,, it helps in strength and cell shape.
nutrition of bacteria (autotroph)
bacteria which utilize CO2 and get energy from sunlight or from other chemical reactions are known as autotrophic bacteria.
photosynthetic autotrophs : these type of bacteria utilize atmospheric CO2 and get energy from sunlight and perform the process of photosynthesis but they use hydrogen sulphide (H2S) instead of water thus releasing sulphur instead of oxygen
chemo autotrophs : these type of bacteria get energy by oxidation-reduction process of various inorganic compounds
nutrition of bacteria (heterotroph)
these bacteria take their food from other living or non-living substances.
parasite : these bacteria obtain their food from the body of other living organisms ,, they’re fully dependent on the host. these bacteria can cause diseases in host sometimes and death can occur.
saprophytes : they obtain their food from dead organisms.
symbiotic bacteria : sometimes ,, bacteria’s form association with other organisms and both of them get benefited.
locomotion in bacteria
bacilli and spirilli bacteria are motile and cocci are non-motile
phototactic bacteria :they move away or towards the light
chemotactic bacteria : they move away or towards due to the presence of chemicals
magnetotactic : they’re able to detect magnetic fields of earth
stages // phases of bacteria
lag phase : inactive phase of bacteria where they prepare themselves for growth
log phase : bacteria grow very rapidly and their metabolic activities are maximum
stationary phase : bacteria face shortage of food, pH changes and less energy so they try to maintain themselves. they also start dying as a result of which multiplication is equal to their death rate and the number of cells is unchanged.
death phase : when conditions are totally unfavourable ,, death occurs rapidly than growth rate.
sexual reproduction in bacteria
(i) conjugation : the genetic material of one bacterial cell is transferred into another bacterial cell through a tube, the conjugation tube, the process is called conjugation
(ii) transduction : the genetic material of one bacterial cell is transferred to another using bacteriophage virus
(iii) transformation : the genetic material of one bacterium is transmitted into another bacteria and due to this information bacterium undergoes changes
advantages of bacteria
decaying of dead bodies : bacteria decompose the dead remains of living organisms and help to clean the world
bacteria in industries : they’re used in multiple industries such as dairy industry,, formation of butter, cheese, alcohol, vinegar, leather.etc.
digestion in alimentary canal : some bacteria’s are present in intestine of man and help in digestion
fertility of soil : it increases the fertility of soil by adding organic substances due to decomposition of dead bodies
genetic engineering : bacteria is used in genetic engineering
medical bacteria : from bacteria ,, many important antibiotics have been obtained
nitrogen fixation : bacteria change nitrogen into its compounds like NO2 and NO3
disadvantages of bacteria
spoilage of food : bacteria spoil our food stuff in large amount by the chemical process
diseases in man, plants : they’re responsible for various diseases in man, animals and plants such as cholera, typhoid or ring disease of potato
cynobacteria
↷ water living simple organisms ↷ do not have true nucleus (prokaryotes) ↷ contain blue green pigments ↷ unicellular ↷ double-layered cell wall ↷ sexual reproduction is absent
nostoc (structure)
the body of nostoc is called thallus, it is very simple in structure. it is found in fresh water ponds, streams, lakes.etc. the thallus consists of many thread like bodies, known as filaments.
the whole filament is covered by a gelatinous sheath, which protects the filament. the gelatinous mass is in colony form, called coenobium
in the filament of nostoc some larger, light yellowish and thick-walled cells are also present called heterocysts. heterocysts take part in reproduction and nitrogen fixation.
nostoc (cell structure)
each cell of nostoc is spherical in shape. it is double layered wall, the outer layer of cell wall is thick, composed of cellulose and pectic compounds. in the cell of nostoc, a true nucleus is absent but the central body acts like a nucleus and controls all the functions.
(i) chromoplasm : it is the outer colored part, it contains color pigments. these pigments are not found in plastid but around this region plasma membrane is present
(ii) centroplasm : it is the inner part of protoplasm, it is colorless but stores food material
nostoc (nutrition)
it contains chlorophyll so it can manufacture their own food material. it also helps in nitrogen fixation
