Classification of micro-organisms Flashcards
Basic structure of viruses is…
- They are very small between 20-450 nano-meters.
- Made up of DNA or RNA.
- DNA or RNA is enclosed in protein coat called a capsid.
- Capsid is made up of protein subunits called capsomeres.
General characteristics of viruses
- Viruses are ultramicrospic (20-450 nm)
- can pass through ultrafilters that would trap most micro-organisms
- have no metabolic or respiratory enzymes
- Only active inside host cells
- Can replicate only inside host cells. therefore they are regarded as parasites
- have strands of DNA or RNA but never both
Basic structure of bacteria
- have a cell envelope, glycolax, a cell membrane, cytosol, ribosomes and a nucleoid.
- don’t have a nucleus
- have single strand of DNA which forms the nucleoid and this nucleiod forms the chromatin body.
- they have flagellae which help bacteria move
- they have fimbriae that help bacteria to stick together
- they have pili which are used in the partial transfer of DNA from one cell to another.
General Characteristics of Bacteria
- smallest cells
- unicellular prokaryotes
- most have cell walls that contain peptidoglycan
- many are heterotrophs which require organic carbon either from decayed matter or living hosts
- heterotrophs can photosynthesise
- range from aerobic to anaerobic
Basic structure of Protista
- plant-like protista are unicellular, contain chlorophyll and they photosynthesise. They have vacuoles, cytoplasm, nucleus, chloroplast, cell wall, cilia or flagellum.
- ## animal-like protista are unicellular and feed like animals. Have similar structure to plant-like protista but they don’t have a cell wall
General Characteristics of Protista
- they are simple unicellular or multicellular organisms that do not show tissue differentiation
- mainly found in water.
- autotrophic or heterotrophic
- they are usually small, but large seaweeds may reach many metres.
Role of decomposers in maintaining balance in the environment and web of life.
- decomposers break down complex organic compounds and release nutrient elements back into the soil.
- process produces by-products like water, carbon dioxide and nitrogen
- break down dead matter using enzymes
Role of nitrogen fixation bacteria in maintaining balance in the environment and web of life.
- bacteria trap free nitrogen, which is converted into ammonia and then into amino acids which are used by plants to synthesise proteins.
- other bacteria use atmospheric nitrogen to form nitrates which plants can use
- denitrifying bacteria reduce nitrates in soil to free nitrogen back into the atmosphere
Role of fungi in maintaining balance in the environment and web of life.
- they form close associations with other plants.
- fungal threads get nutrients from the roots and provide water and mineral salts to the roots in return.
What is parasitism?
when one of them benefits and the other doesn’t benefit and is harmed. A win-lose situation.e.g when a virus attacks the human immune system in the form of HIV/AIDS.
Commensialism
- one partner benefits the other does not benefit, but is not harmed.
Mutualisms
- when both partners benefit. e.g nitrogen fixing bacteria in legumes.
Describe effect and management of HIV/AIDS
CAUSES:
- unprotected sexual intercourse
- across placenta to an unborn child and in birth
canal as child is being born.
- coming in contact with infected bodily fluids like
blood.
SYMPTOMS:
- during early stages you might show flu-like symptoms then after that opportunistic infections will target you.
TREATMENT:
- during early stages person infected will be offered co-trimoxazole antibiotic to consume daily to prevent opportunistic infections
- when a person’s CD4 cell count starts to drop rapidly they will have to consume ARV’s to prevent further growth of virus.
PREVENTION:
- do not have unprotected sex use barriers like condoms
- avoid contact with bodily fluids by wearing gloves when handling bodily fluids.
- providing HIV positive pregnant women with guidance and treatment to prevent transmission of disease onto unborn child.
Describe effect and management of tuberculosis
CAUSES:
- bacteria becomes active when a person has a weak immunity which could be caused by HIV, old age or some other medical conditions.
SYMPTOMS:
- tiredness, coughing, presence of blood in suptum, chest pains, fever, sweating, poor appetite and loss of weight.
TREATMENT:
-usually with a course of four standard anti- TB drugs. They can also get a streptomycin injection.
PREVENTION:
-TB can be prevented using a vaccination.
Describe effect and management of malaria
CAUSES:
- it is caused by being bitten by the female anopheles mosquito which is the carrier of the disease
SYMPTOMS:
- early stages infected person shows flu-like symptoms
- afterwards they will show the following symptoms: fever, muscle aches, progressive headaches, neck stiffness, convulsions and coma
- if not treated early malaria is very fatal.
TREATMENT:
-uncomplicated malaria is treated with oral quinine as well as other anti-biotics like doxycycline/ artemther-lumenfantrine.
- severe malaria is treated with intravenous quinine.
PREVENTION:
- wear long sleeved shirts and long pants tucked in pants in the evenings when mosquitoes are feeding
-use insect repellents on exposed skin
- sleep under bed nets
-cover windows and doors with gauze
-empty areas of standing water around the house so that mosquitoes can’t breed
- take anti-malaria prophylaxis in a malarial area.
- pregnant women and young children should not be in malarial areas
