Micro Organisms Flashcards
Explain micro organisms fully
- Importan role in the environment
- affect the health of other living organisms
- Cause diseas = pathogens
- Used by humans for own needs ( biotechnology)
- Acellular = viruses
- Cellular = bacteria; protists and fungi
- Prokaryotes = lack membrane bound nucleus / organelles ( bacteria )
- Eukaryotes = have membrane bound nuclues & organeles ( protists& fungi)
Explain viruses structure fully
- Acellular ( no nucleus; cytoplasm / organelles)
- Outer protein coat or capsid
- Surrounds inner core of DNA / RNA - Infect plant cells contain RNA
- Infect animal cells = DNA / RNA but never both
- Retroviruses = viruses with RNA
- Infect bacteria = bacteriophages
- Lipid by-layer covered capsid in some ( rabies; influenza)
- Protects virus from host’s enzymes
- Spike help to attach to host
Explain virus characteristics fully
- Different shapes
- Are pathogens as they cause disease
- Reproduce = viral nucleic acid replicates using host cells materials to make many new viruses
- Obligate intracellular parasites ( only reproduce inside a living host cell)
- Extremely small ( only seen using electron microscope)
- Not really living ( don’t perform metabolic functions of living organisms eg resp; feeding; gaseous exchange; excretion; growth)
- Diseases = chicken pox; mumps; HIV
Explain bacteria structure fully
- Slime capsule = protect from desiccation and action of enzymes
- Cell wall = made of peptidoglycans
- Cell membrane = semi permeable ; had mesosomes
- Mesosomes = incr SA and act as mitochondria and ER
- Ribosomes = produce proteins and enzymes
- Plasmid = small circular pieces of DNA
- Flagellum = allows bacteria to move
- Chromosome ( nucleoid ) = made up of a single strand of DNA
Explain bacteria characteristics fully
- Smallest living organisms
- Unicellular prokaryotes
- Belong to the Kingdom Monera
- Inhabit all environments
- Most abundant and diverse group of organisms on the earth
- Some = pathogens
- Many = useful to humans and environment
- Exist in single cells or colonies
- Respire aerobically and anaerobically
- Heterotrophic or autotrophic
- Reproduce asexually by binary fusion in favourable conditions
- Unfavourable conditions = forms endospores ( hard; protective capsules that remain dormant until fav conditions return)
Explain protist structure fully
- Kingdom Protista
- Reproduce asexually by binary fusion in fav and unfav cnditions
- Animal-like = protozoa
- heterotrophic; some parasitic; move using psuedopodia; others move by cilia or flagella) - Plant-like = euglena; algae; phytoplankton
- Autotrophic as can make own food by photosynthesis due to containing chlorophyll - Fungus-like = slime moulds
- Decomposers; heterotrophic; digest own food releasing enzymes into organic matter and absorbing nutrients
Explain fungi structure fully
- Unicellular = yeasts
- Multicellular = breadmould ( Rhizopus ) and mushrooms
- Consist of branches of interwining ‘ threads ‘ called hypae - 3 types of hypae : vertical= sporangiosphres
horizontal = stolons
penetration = rhizoids
( mass of hypae = mycelium) - Hypae = aseptate ( no cross walls ) and multinucleate
- Eukaryotes ( true nuclei)
- ## Unique cell wall made of chitin ( used to make up insect exoskeleton)
Explain fungi characteristics fully
- Belong to the kingdom fungi
- Lack chlorophyll and therefore are heterotrophic
- Some = parasites and feed on living material ( eg. athletes foot; thrush and ringworm)
- Fav conditions = reproduce asexually by producing and releasing spores from the sporangia
- Most = saprophytes / decomposers and live off dead organic plant and animal matter
- EG. Bread mould and mushrooms: rhizoids secrete an enzyme into the substrate hat breaks down organic material into soluble form eg glucose ( extracellular digestion)
- Rhizoids then absorb these soluble nutrients
What is symbiosis and what are the 3 types
- Close association between two different species
1) Mutualism : both organisms benefit from relationship
2) Commensalism : 1 organism benefits, the other neither benefits nor is harmed
3) Parasitism: 1 benefits and the other is harmed
Explain Nitrogen - fixing bacteria in plants fully for symbiosis
- Mutualistic relationship
- Nitrogen = needed to make proteins in living organisms
- Plants cannot use atmospheric nitrogen ( only use it = nitrates form) - Nitrogen fixing bacteria like Rhizobium live in the root nodules of legume plants
- They change gaseous nitrogen into nitrates which plants can use to make amino acids - Rhizobium bacteria benefit by obtaining nutrients; water and a favourable habitat from the legume plant
- Legume plant benefit by obtaining nitrates from the bacteria which are then used to produce amino acids
Explain E.Coli in the human intestine in relation to symbiosis
- Mutualistic relationship
- Bacteria = found in the large intestine of humans
- Play a very important role in the nutrition of humans
Humans benefit by E.Coli:
1) Produces vitamin B12 for humans
2) Stops the growth of pathogenic bacteria in the gut
3) Produces vitamin K ( prevents blood clotting)
E.Coli benefit by obtaing nutrients and a favourable environment in the gut of the human in which to grow and reproduce
Explain HIV causes; how it is spread and symptoms
- Virus
- Human Immunodeficiency Virus
- Attacks the immune system, particularly the CD4 cells or T-Lymphocytes
- During incubation period = virus invades t - lymphocytes and uses its DNA to make copies of itself
Spread by:
- Unprotected sex with an infected partner
- Transfer of blood from infected person through sharing of needles or accidentally
- Infected pregnant mother to unborn baby
Symptoms:
- Rapid weight loss
- Shingles ( painful nerve disease )
- Enlarged lymph nodes and joint pain
- Frequent fevers and sweats
- Thrush
- Certain cancers
- Persistent skin rashes
Explain how HIV progresses and the treatment
Progression:
- Slow progression with a long incubation period
- Initial infection = unnoticed
- HIV antibodies appear in infected persons blood 6wks later
- Continued destruction of T-Lymphocytes by the HIV weakens immune system until it is so low the person suffers from opportunistic infections
Treatment:
- Get tested
- if negative = prevent infection ( ABC)
- if positive = manage disease and prevent transmission to sexual partners
- Treat with anti-retrovirals
- start when CD4 cell count is 200-350
- dont cure just stop viral replication and allows immune system to recover
-Monitor viral load
- to determine if ARVs are working properly
- Care for emotional and mental health
- support from family and friends
- Financial planning
- Boosting immune system
- to slow down effects of HIV infection
- Pregnant women = use ARVs during pregnancy and labour
- baby also given ARVs for a few days after birth to counteract exposure during labour
- PEP ( post exposure prophylactic)
- health care workers who may have been exposed to HIV by accident
- Treatment must start within 24hr and continue for 28days
Explain drug resistance fully
- The ability of disease causing germs to continue multiplying despite the presence of drugs that usually kill them
- Drugs for HIC and TB consist of multiple drugs of at least 3 classes to attack the bacterium at a different stage of it replication
- if allowed to replicate it will do so at an extremely rapid rate ( as a result mutations are common ) - One or more of the mutations = new strains of HIV or TB and might block the working specific drug making them less effective or ineffective
Development:
- Not taking medication exactly as prescribed
- Unsafe sex while on a drug regiment can result in resistant HIV strain being transmitted
- Poor absorption of the particular medication can lower blood levels which increases the chance of mutations
Explain innate immunity fully
Part A:
- Prevents pathogens entering the body
- First line of defence
- Physical/external barriers
- Chemical secretions ( stomach acid; tear fluid; mucus in nose or throat) helped by sneezing or coughing reflexes to kill; trap or expel pathogens
Part B:
- Second line of defence
- Prevents the spread of pathogens to other areas in the body
- Fever : raised body temp = not favourable for bacterial production and restricts their growth)
- Inflammation: causes redness; swelling; pain; heat at site of infection
- Blood vessels widen allowing more blood carrying immune cells to reach the area faster
Other:
- Acquired without immunisation taking place
- Passive = antibodies passed from mother to child via placenta or breast milk
- Active = immunity develops through contact with pathogens which stimulates the immune system to produce antibodies
