Unit 1.1: Microorganisms and disease Flashcards
(149 cards)
1
Q
Biodiveristy:
A
The great variety of organisms found on earth.
2
Q
Prokaryotes (monera):
A
Organisms without a true nucleus/ cell organelles
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Q
Eukaryotes: (4 kingdoms)
A
organisms with true nucleus and cell organelles
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Q
macro-organisms:
A
Can be seen with naked eye
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Q
micro-organisms
A
Cannot be seen with naked eye
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Q
Pathogenic:
A
disease-causing
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Q
non-pathogenic:
A
harmless
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Q
Inert:
A
inactive
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Q
Acellular:
A
Not true cell
(no cytoplasm / organelles)
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Q
Classification criteria
(observable similarities)
A
- Body structure
- Means for obtaining food
- Method of reproduction
11
Q
The role of evolution:
A
- Increasing diversity : speciation & mutation
- Decreasing diversity : extinction
12
Q
Rule of evolution:
A
Trend : SIMPLE TO COMPLEX
(prokaryote - eukaryote)
(unicellular - multicellular)
13
Q
What do micro organisms do?
A
*viruses, bacteria, fungi, protists
Pathogenic / non-pathogenic
Disease causing microbes = PATHOGENS
14
Q
viruses:
A
Differentiation : SHAPE
- pathogenic organism
- cannot classify as living
- INERT: uses host cells materials to repoduce
15
Q
Reproduction of Virus:
A
ONLY REPRODUCE WHEN INSIDE host cell.
(lies dormant in bloodstream)
- survives in living cell of organisms
- viral nucleic acids make copies = new copies
(replicates & mutates)
16
Q
Characteristics of Virus:
A
- extremely small (electron microscope)
- non-living organism
- obligate intracellular parasites
- reproduce inside living cell
- ACELLULAR
- Pathogenic
- Can remain in dormant state, until immune system cannot suppress
17
Q
Structure of Virus:
A
- Acellular (only contains NUCLEIC ACID)
- Simple structure DNA / RNA
- Capsid (protein coat) surrounds nucleic acid = PROTECTION
- ** envelope (lipid) “enveloped viruses”
(protects from host’s enzymes which try to destroy it)
18
Q
Effect of Virus on Body (HOST CELL)
A
- Infected cells can be destroyed.
- Mutation in host’s chromosomes
- Immune system becomes activated
(fever, tiredness, disease)
19
Q
Symbiosis:
A
Close association between two different species
- Mutualism
- Parasitism
- Commensalism
20
Q
Mutualism:
A
Both benefit
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Q
Parasitism
A
One benefits, other is harmed
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Q
commensalism
A
Neither is harmed, one benefits
23
Q
Bacteria:
A
Ancestors of Bacteria = CYANOBACTERIA
unicellular
1st to photosynthesise
24
Q
Bacteria General characteristics:
A
- Monera
- Diverse & abundant group of organisms
- Inhibit all enviros
- pathogenic / non-pathogenic
- unicellular
- bigger than virus
- non pathogenic = autotrophs
- pathogenic = parasites
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Extremophile:
Lover of extreme conditions / habitats/ environments
(no temperate conditions)
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Spherical =
cocci (coccus)
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rod-shaped =
Bacilli (bacillus)
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spiral shape =
spirilla (spirillum)
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comma- shaped =
Vibrios (vibrio)
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Bacteria can also exist in:
Chains = Streptococcus
Clumps = Staphylococcus
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Bacteria Reproduction
Favourable conditions : BINARY FISSION (asexual process)
- single cells divides into 2 with identical DNA
Unfavourable (hot & dry)
- survive by becoming dormant, form spores with thick protective coat
When favourable conditions return - split open to release.
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Bacteria Structure
- unicellular & simple
- protective rigid cell wall
- Large molecules = PEPTIDOGLYCANS
- Prokaryotes
- Single chromosome = closed loop of DNA
- Pathogenic bacteria = Waxy capsule
- Flagella = tendril-like outgrowths
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Effects of bacteria on hosts body:
Pathogenic bacteria infect bodies to get food
1. Destroy body cells
2. Absorb nutrients from body fluids
3. Releases toxins = HARMS
(rash , temp)
*stops reactions in host cells
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Waxy capsule:
protection against defence of host's body
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Flagella:
inefficient locomotion
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Protista Common Characteristics
- Single - celled
- Eukaryotes
- Can be joined AMOEBA
- moist enviros
- reproduce asexually
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Protista Variable characteristics:
- size
- Autotroph / heterotroph
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autotroph:
Able to make own food
(photosynthesis)
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heterotrophs:
unable to make own food
(nutritionally dependent
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Plant like Protists = ALGAE
- simple celled
- Aquatic eukaryotes
- Autotrophs : base of aquatic food chain
- Releases O2
- Mostly free floating = sessile
- Reproduce asexually
*unicellular & microscopic*:
Diatoms , cells walls containing silica & dinoflagellates
*multicellular & macroscopic*
seaweeds
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sessile:
fixed/ immobile
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Animal - like Protists = PROTOZOANS
- unicellular
- microscopic
- heterotrophs
Amoeba : phagocytosis (intracellular)
Swim: in search of food
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Protozoan grouping based on:
means of locomotion
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1. Amoeboids
Move & feed: cytoplasmic projections = PSEUDOPODIA
eg. free living Amoeba
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2. Ciliates
Hair- like structures = CILLIA
Swim and capture food
eg. Paramecium
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3. Flagellates
flagella : locomotion
eg. Giardia (Diarrhoeal disease)
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4. Parasites
non- motile
eg. Plasmodium = MALARIA
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Plankton
numerous microorganisms floating in currents of open oceans
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types of plankton:
Phytoplankton : plant like unicellular protists (algae)
Zooplankton : bacteria & animal-like unicellular protists (protozoans)
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taxonomist:
A person who classifies organisms into groups based on shared features.
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Classification of FUNGI
- similar ecological roles =
DECOMPOSERS of organic matter
(lives symbiotically with tree roots)
Similar Anatomical & Biochemical features
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Fungi General Characteristics
- useful : nutrients
- invisible
- free-living : soil, air, dead matter
- Heterotrophic
- Saprotrophic feeding: decaying organisms
- Parasitic fungi : feeding & harming host
(thrush, athletes foot)
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Fungi examples:
yeasts
rusts
smuts
mildews
moulds
mushrooms
toadstools
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Saprophytic feed:
Release digestive enzymes that break down organic matter to be absorbed
(extracellular digestion occurs)
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Lichen:
mutualistic
fungi & algae living in 1 structure
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Mycorrhizae
mutualistic
fungi & plant roots
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Reproductive cell conditions
Favourable
1. Damp
2. Dark
3. Warm
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Fungi reproduction:
ASEXUALLY
reproductive cells : "spores"
SEXUALLY
resistant zygospores (unfavourable)
BUDDING = vegetative reproduction
metabolises
(yeasts)
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Substrate:
What fungi lives on
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Spore:
microscopic (singular) lands to create Hyphae
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Fungi structure:
- multicellular
- unicellular : yeast
mass of branched filaments = HYPHAE
- enclosed : rigid cell wall
- vegetative body : Mycelium
- reproduces: spore producing bodies
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mycelium:
vegetative body of cells / threads
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Hyphae
(ability to make cells)
- cell wall
- tubular
- cytoplasm
- many nuclei (DNA)
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Multicellular fungi
Mycelium with 4 types of thread in it
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1. Hyphae
threads in substrate
cell parts:
- tubular cell
- cytoplasm
- cell wall
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2. Stolon:
- Horizontal, aerial Hypha
- surface of substrate
- spreads mould / mycelium horizontally
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3. Rhizoids:
= feeding hyphae in substrate
- Digest & absorb
extracellular
- starch --> glucose (cell resp)
- absorption of glucose
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4. Sporangiophore:
Vertical, aerial hypha
reproduction carries sporangium
surface above
top = sporangium (makes spores of nucleus, cytoplasm, cell wall)
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FUNGI Asexual reproduction process explained in words
1. Aerial hyphae grow vertically onto substrate's surface
2. Nuclei & cytoplasm collect in tip of hypha and it swells
3. A wall separates the sporangiophore (thread) from the sporangium (tip)
4. Spores from Nucleus & Cytoplasm in cell wall
5. Spores mature
( white - green - black)
6. Wall pushes upwards - puts pressure on sporangium contents -
bursts
- spores released & dispersed
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Types of diseases:
1. Viral (HIV)
2. Bacterial (TB)
3. Protistan (malaria)
4. Fungal (thrush)
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what is HIV?
Human Immunodeficiency Virus
compromises CD4 cells : attacks & weakens immune system
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Stage 1 HIV
window period (early infection)
unprotected sex --> 12 weeks
- flu like symptoms
- HIV antibodies negative
- contagious
CD4: 600 - 1200 / ml blood
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Stage 2 HIV
silent infection (asymptomatic)
- damaging immune system
- CD4 decreases
- contagious
- children : faster progression
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Stage 3 HIV
Symptomatic
CD4: 150 - 500 /ml
- swollen lymph nodes, shingles, rash
-- TB, thrush, herpes
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Stage 4 HIV
AIDS
- body cannot resist infection
CD4: below 200
*opportunistic infections
TB, pneumonia, meningitis
Cancers & weight loss
- central & peripheral nervous system : neurological symptoms & deterioration
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Immune system:
body's defence against infection
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how are CD4 cells destroyed?
HIV uses materials of CD4 cells to make more viruses
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opportunistic virus:
when immune system is weak, virus easily manifested
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untreated HIV =
HIV multiplies and damages immunity
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HIV treatment:
- CD4 count
- Antiretrovirals
(stop viral replication)
- monitoring viral load
- good diet
- avoid substances
- good well being
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Bacterial disease: TB
*Mycobacterium tuberculosis*
-chronic bacterial infection : attacks organs
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How is TB contracted?
Through the air in moisture droplets that are exhaled by infected person
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Bacterial infection:
- contagious
- chronic
- all organs
- mainly lungs = Pulmonary TB
- spreads: transmission
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TB bacillus structure:
rod-shaped
waxy coat
- protects against:
1. dryness
2. heat
3. host's immune system
waxy coat
fibrous capsule - latent, dormant
weak immune system: TB multiplies rapidly
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Symptoms of infection:
tired
weak
persistent cough & blood
weight loss
night sweats (fever)
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Problems associated with infection:
stays active until treated
can mutate & become drug-resistant
can be fatal
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Treatment of TB
(DOTS)
Directly Observed Therapy Short Course
First line of defence drugs
- antibiotics
- multiple types
monitored by health professionals
must finish course of antibiotics
6 months long course
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Problems associated with NOT finishing the course of treatment
- pro longed illness
- increased reinfection
- mutations occur when TB reproduces
- builds resistance
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Resistant strains of TB:
Bacterial resistance occur to antibiotics
MDR-TB: First 2 sets of antibiotics can't kill it
(expensive)
XDR-TB: resistant to 3 + antibiotics
(fatal)
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TB sigma in society:
Poverty association
Epidemic
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poverty association:
Malnutrition
overcrowding
lack of medical care
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possible epidemic can be prevented by:
screening & quick diagnosis
treatment
less overcrowding
less malnutrition
education
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What does TB education involve?
1. Health care workers
2. Schools
3. topics & healthy eating
- immunity
- spread
- symptoms
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HIV & TB relationship:
HIV weakens immune system
- Body can't suppress HIV / TB
- TB is opportunistic when HIV is present
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Malaria
(PROTIST disease)
*Plasmodium falciparum*
= predominant species of malaria parasite
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Transmission:
mosquito bite
- female Anopheles mosquito
- VECTOR
- uses human blood to feed her eggs: PARASITE = sucked up with blood
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Plasmodium
Structure & function
- unicellular
- Protozoa
- crescent shaped (moon like sliver)
- parasite:
uses haemoglobin in RBC to make own proteins
- reproduces in liver
- enters RBC to eat haemoglobin
- RBC destroyed
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Malaria symptoms
fever
chills
headache
muscle aches
vomiting
diarrhoea
14 days after bite : symptoms
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Problems post malaria infection:
Later complications:
cerebral malaria (brain)
severe anemia)
kidney failure
death
dehydration
brain damage
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Management of Malaria
quick diagnosis - stops reproduction
Destruction of mosquitos
treatment
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Destruction of mosquitos using:
ITNs :
- physical barrier
- traps mosquitoes
- CO2 attracts
insecticide kills - spray / 3 yrs
Chemical spraying DDT
(agent orange)
- waterbodies
- destroys ecosystems
- human deformities
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Treatment of Malaria:
COARTEM
97% effective
on pill , many drugs
- artemisinin = chinese herb
(resistance?)
CHLOROQUINE, quinine, doxycycline
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MALARIA
Individual Costs
medication: treatment & prevention
- funeral
- income loss
- unemployment
- prolonged illness
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MALARIA
Government costs
- health facilities & staff
- medication
ITNs
DDT
- tourism loss of income
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Fungal Disease: THRUSH
*Candida albicans*
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Effects of Thrush:
- mucous membranes affected
- weakens membrane = vulnerable
- occurs harmless in intestine
Healthy = immune system & bacteria destroy fungi
*certain conditions
overgrowth = infection
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Causes of Thrush
- many antibiotics
(reduces intestinal bacteria)
- AIDS / cancer
- pregnancy
- Birth control
- Stress
- Poor diet
- unmanaged diabetes
*warmth & moisture caught in genitals & folds
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Treatment of Thrush
Oral thrush = antifungal mouth wash
Vaginal thrush = topical antifungal meds / ointment
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topical:
Applied / inserted directly on body's surface (outside)
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immunity:
The ability of an organism to resist / fight off a particular infection/ pathogen / toxin.
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Immune response:
How the immune system acts to stop infection or invasion by pathogenic microorganisms.
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Plant immunity
(pathogens harm:)
1. Plant growth
2. reproduction
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Bacteria unable to enter plant:
Stomata can be closed to actively limit bacterial resistance.
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Systemic Acquired Resistance:
1. Pathogens have specific SHAPE
2. Plant RECOGNISES pathogen shape
3. Infected cells make SALICYLIC ACID
(plant hormone - chem messenger)
4. SA activates DNA to attach pathogens and stop reproduction
5. Cells SELF-DESTRUCT
barrier occurs in plant
stops spread
6. SA moves to UNINFECTED parts
(makes chemical to resist pathogen)
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Types of Immunity:
1. Passive (natural)
2. Natural (innate)
3. Active
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Passive immunity:
The immunity present in babies.
inherited mother's immune system of antibodies.
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Natural immunity:
A person gets a disease and produces antibodies during disease that will protect from future infections
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Active immunity:
A vaccination is given to a person to make the body manufacture antibodies
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Acquired immunity = obtained
Development of antibodies in response to antigen exposure
transmission of antibodies through placenta
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Antigen:
A foreign protein on the surface of a pathogen.
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Antibody:
A cell made by the body in immune response
= immunoglobulins
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1st line of defense:
Skin
- prevents entry of pathogens
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2nd line defence
Immune response
2.1 Primary:
- destroys and prevents spread of pathogens
inflammation (local response)
2.2 Secondary:
- immune system action
Destroys pathogen
Makes memory cells
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Phagocytosis:
squeeze through gaps in capillary wall.
enzyme destroys pathogen
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White blood cells:
Amoeboid shape & movement
leave blood vessels and enter tissues
LYMPHOCYTES
PHAGOCYTES
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LYMPHOCYTES
B lymphocytes & T lymphocytes
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B lymphocytes:
1. make antibodies
2. become memory cells
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T lymphocytes
CD4 cells
- start immune response
Killer T cells
- destroy body cells that are infected & parasites
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Phagocytes:
Macrophages
- large lymphocytes change shape to engulf
PHAGOCYTOSIS
1. search
2. engulf
3. destroy by enzymes
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Immune response: How the B lymphocytes work:
1. Antigen on pathogen recognised by specific B. L (lock-key)
2. B. L clone themselves quickly
3. B. Lymphocytes make antibodies
4. Antibody & antigen on pathogen surface
5. Pathogen destroyed/ neutralised by antigen
6. Some B. L stay on as memory cells
7. Memory cells respond quickly to 2nd invasion by same pathogen
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Pathogen NEUTRALISED / DESTROYED:
1. Pathogen burst
2. Pathogen labeled for phagocytes to destroy
3. Antibodies clump pathogens together
(weaken = easier to ingest_
4. Neutralise toxins produced by bacteria
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Species:
1. Able to interbreed
2. Produce fertile offspring
3. All possible organisms of species
4. Distributed worldwide
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Population:
1. Group of organisms
2. Same species
3. Same habitat @ Same time
4. Fertile offspring
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Antibiotics:
Medicines that target specific pathogenic bacteria
(targets bacterium cell)
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Non - resistant bacteria:
- un favourable gene
- dies
- population decreases
- extinct
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Resistant bacteria:
- favourable gene
- reproduces
- survive
- population increases = multiplies
- resistant bacteria
(super bugs)
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Antibiotic resistance
NATURAL SELECTION
resistant / non resistant bacteria
over time - population =
resistant bacteria ONLY
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Vaccine:
(injection / oral)
suspension of dead, weakened or fragmented micro organisms or their toxins.
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what do vaccines do?
Stimulates production of antibodies by B lymphocytes = immunity
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Antibodies stay in blood =
developing immunity
- Artificially acquired immunity
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Vaccination / Immunisation:
Process of giving vaccine to a person to make them immune to disease
Does not get disease,
only symptoms
Memory cells left behind
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Why do antibodies not cause disease?
pathogens dead & weakened
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Change DNA & RNA =
Genetic engineering
self replicating: codes for every protein in body
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Biotechnology:
The manipulation and use of microorganisms in a laboratory to make substances which humans want, through the process of genetic engineering to make Genetically Modified Organisms (GMOs)
145
What does biotechnology produce:
medicines (antibiotics / insulin)
& food
146
Antibiotics
BIOSYNTHESIS
secreted by fungi
- Streptomyces: grow in soil
- Penicillium: grows on fruit
147
Collection of antibiotics:
- mould organism put into VAT / fermenter with nutrients
(sugar / amino acids)
- mixture stirred and kept at 25 degrees for 5 days
- grow rapidly: producing penicillin
(taken out of broth & purified)
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Insulin:
Hormone with regulates concentration of blood sugar.
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Genetic engineering of insulin:
*Diabetes mellitus*
Produced bacteria which makes human insulin
(*Escherichia coli*)
- extraction of human somatic cells of gene
- gene inserted into bacterium
- genetically engineered bacteria with insulin gene
- grow in large vats
- Insulin: extracted & purified
