Infection and Response Flashcards
Pathogen
A pathogen is a harmful microorganism that causes diseases.
Types of pathogens
Bacteria
Fungi
Viruses
Protists
Ways diseases are spread
Some examples: Air, Water, Lifestyle, Vector, Direct Contact
Controlling the spread of communicable diseases:
Vaccination
Isolation
Reducing Vectors
Hygiene
Bacteria
- Cause diseases in animals
- Single celled organisms
- Produce toxins
- Do not have a nucleus (prokaryotik)
Examples include: Gonorrhoea and Salmonella
Gonorrhoea
Bacteria: Sexually Transmitted (STD)
Symptoms: thick yellow discharge from genitals, pain when urinating.
Prevention and Treatment: antibiotics, protected sex
Salmonella
Bacteria - Digested bacteria from food
Symptoms: fever, vomiting, diarrhoea, cramps.
Prevention: poultry are vaccinated.
Fungi Example
Rose Black Spot:
Spread by water and air
Symptoms: purple or black spots on leaves which droop and fall. Reduces photosynthesis.
Treatment: fungicides, remove infected leaves.
Protist Example
Malaria:
Spread by mosquitos (VECTOR)
Symptoms: episodes of fever, can be fatal.
Prevention and Treatment: control vector, anti-malarial medication, mosquito nets, vaccination.
Viruses
- Cause diseases in all living things
- Smaller compared to bacteria
- Neither living or dead
- Invade cells and replicate themselves inside them, before
bursting out, killing the cell and damaging tissues in the
process.
Measles
Virus - spread by inhalation of droplets in the air
Symptoms: fever, rash, can be fatal
Treatments: vaccination (children)
HIV
Virus - Sexually Transmitted/ Blood/ Exchange of fluids (drug users)
Symptoms: flu-like symptoms; virus attacks the immune cells, which can lead to AIDS thus causing cancer and other serious diseases.
Prevention: protected sex; don’t do drugs or use someone else’s needle.
TMV
Virus - direct contact of plants/ vectors/ soil remains infected for long periods of time
Symptoms: mosaic pattern of discolouration as chlorophyll is destroyed. Reduces photosynthesis.
Prevention: remove infected plant, use new soil.
Plant Defences: Physical Barriers
- Cellulose cell walls: provide a barrier for infection
- Tough waxy cuticle: II
- Bark on trees: dead cells that can fall off and remove
bacteria and vectors.
Plant Defences: Chemical Barriers
- Antibodies
- Anti-bacterial chemicals
- Poison production: discourage herbivores
Plant Defences: Mechanical Defences
- Drooping and Curling: dislodge vectors
- Mimicry: deter herbivores by mimicking unhealthy plant
- Thorns and Hairs: discourage herbivores
Detection and Identification of Plant Diseases
- Stunted Growth
- Spots on Leaves
- Areas of rot and decay
- Growths
- Pest Infestation
- Discolouration
Non-specific defences of humans
- SKIN: antimicrobial secretions
- NOSE: mucus
- STOMACH: acidic
Phagocytes
White Blood Cells
Englufs the pathogen.
Enzymes that digest and destroy the pathogen are released.
Lymphocytes
White Blood Cells
1. Release antitoxins to neutralise the harmful toxins
produced by bacteria. Anti-toxins have a complimentary
shape according to the type of toxin.
- Produce antibodies complimentary to the shape of
antibodies (protein on surface of virus that the
lymphocyte uses to detect the virus - also how memory
cells recognise viruses when reinfected) - Memory Cells - produce a specific type of antibody if the pathogen re-enters the body. This results in a quicker response (and larger) from the immune system which is known as a secondary immune response.
Why can’t antibiotics kill viruses?
Viruses replicate inside of the cells therefore antibiotics cannot destroy them without damaging body cells.
The process which bacteria divide and multiply:
BINARY FISSION
Monoclonal Antibodies
Monoclonal antibodies are clones of your body’s antibodies that are made in a laboratory, meant to stimulate your immune system.
Made by cloning a lymphocyte that specifically produces that antibody - see “How are monoclonal antibodies produced?”
How are monoclonal antibodies produced?
- Mice are injected with a specific particle that we need
antibodies for - stimulates the production of
lymphocytes.
LYMPHOCYTES cannot divide, they can produce antibodies.
- TUMOUR CELLS are cultured and can divide and multiply
to form clones. - The desired lymphocytes are fused with the tumour cells
to create HYBRIDOMA CELLS that multiply. The
hybridoma cells can divide like tumour cells and produce
antibodies like lymphocytes. - A large number of monoclonal antibodies can then be
produced, collected and purified for use.
Use of monoclonal antibodies
1) RESEARCH - specific monoclonal antibodies can be
binded to a fluorescent dye so that specific molecules
can be located in cells and tissues.
2) TREATMENT - monoclonal antibodies can deliver toxic
chemicals and drugs specifically to cancer cells in the
body.
3) TESTING - pregnancy tests.
HCG
Pregnancy hormone that is detected by monoclonal antibodies in pregnancy tests.
Digitalis (heart drug - pacemaker) originates from…
foxgloves
Aspirin originates from…
willow
penicillin originates from…
penicillium mould
Thalidomide is…
a sleeping pill. caused birth defects so war banned.
Thalidomide is now used to treat…
leprocy
MMR vaccine creates immunity against…
Mumps
Measles
Rubella
