infection and response Flashcards
communicable disease vs non communicable
communicable: can be spread from person to person via pathogens
non communicable cannot
what is a pathogen and what are the types
microorganisms that cause infectious diseases
bacteria
viruses
protists
fungi
how are pathogens spread
air
water
direct contact
how to prevent spread of pathogens
- basic hygiene eg washing hands
- condoms
- isolate patients
- vaccinations
how does bacteria make you feel ill
- reproduce rapidly when inside body
- release toxins, which damage tissues and make us feel ill
how do viruses make you feel ill
reproduces rapidly inside cells, causing them to burst and die which causes us to feel ill
what disease is measles and give causes, symptoms, prevention
virus
- spread when droplets in air from cough or sneeze are inhaled
- fever, red skin rash, damaged breathing system, damaged brain, fatal
-vaccination when young
what disease is hiv and give causes, symptoms, and preventions
virus
- sexual contact, exchanging fluid eg sharing infected needles
- flu symptoms, damages immune system until other infections & cancer cells cannot be fought off (late stage HIV, or AIDS, - fatal)
-antiretroviral drugs stop the virus replicating - taken for lifetime
what disease is salmonella and what are the causes, symptoms, and preventions
bacterial
- ingesting infected food
- fever, abdominal cramps, vomiting, diarrhoea
- chicken vaccinated
what disease is gonorrhoea and what are the causes, symptoms, and preventions
bacterial
- sexual contact
- thick yellow or green discharge from penis/vagina, pain when urinating
- originally penicillin, however strains of bacteria have become resistant. condoms, getting tested for antibiotic prescriptions
what disease is malaria and what are the causes, symptoms, and preventions
protist
- person with malaria bitten, pathogen passes into mosquito (vector), mosquito bites another person, pathogen passes into person
- fever, fatal
- draining still water to stop breeding, insecticides, & mosquito nets
what disease is tobacco mosaic virus and what are the symptoms
virus in plants
- discolouration in mosaic pattern, reduces phtsyths & growth
what disease is rose black spot and what are the causes, symptoms and preventions
fungal in plants
- spread by water/wind
- purple/black spots, turns yellow & fall off. reduces phtsyths & growth
- fungicides, destroy infected leaves
causes of plant damage
insects aphids extract nutrients from plant, stunting growth
signs of plant disease
- presence of insects that may carry disease
- discolouration
- spots on leaves
- stunted growth
- decay
- abnormal growths
- malformed stems or leaves
how to identify plant disease
- manuals and websites
- in a lab
- testing kits using monoclonal antibodies
how can plants get disease without pathogens
plant ion deficiency disease
lack of:
- nitrate ion: prevents protein synthesis, stunts growth
- magnesium ion: chlorophyll cannot be made, causing chlorosis
plant physical defences
- cellulose cell wall
- leaves covered in waxy cuticle
- dead cells around stem, eg bark
makes it difficult for microorganisms to penetrate
plant chemical defences
- produce antibacterial chemicals, kills bacteria
- produce poison to deter herbivores
plant mechanical defences
- thorns or irritable hairs to deter herbivores
- leaves that droop or curl when touched, knock off insects
- mimic other organisms eg mimic stinging nettle
bacteria vs virus
bacteria can reproduce every 20 mins, viruses can only reproduce inside a host
viruses cannot be killed by antibiotics, bacteria can
define health
the state of physical and mental well-being
why might some people be more likely to catch a disease than others?
diseases can interact
eg TB can usually be fought off by immune system, however someone with HIV will have defective immune system
disease can cause another
eg HPV is usually typically harmless, however can cause cervical cancer
infections can be triggered by immune system
eg allergies, asthma, dermatitis
mental illness can be triggered by physical illness
eg arthritis can cause depression from isolation and lack of movement
how do humans fight disease
- non specific defence system
- immune system
what is the non specific defence system with specifics
features of body that prevent pathogens entering
Skin - protective layer, has dead cells (hard to penetrate), secretes sebum (kills bacteria), able to form scabs when layer is damaged
hair & mucus - trap pathogens
cilia - line trachea and bronchi, covered in mucus (traps pathogens) and wafts them to throat to be swallowed to stomach
stomach - hydrochloric acid kills pathogen
ways that immune system fights disease
white blood cells
- phagocytosis
- antibodies
what is phagocytosis?
When white blood cells detect, ingest, and destroy pathogens using enzymes
how do white blood fight disease using antibodies and antitoxins?
- pathogen has antigens on surface
- WBC produces antibodies
- binds to antigen & triggers other WBCs to destroy
- antibody is specific to pathogen
- wbc multiplies amd stays in body, fights faster if pathogen invades again
- WBC produces antitoxins
- binds to toxins to prevent them damaging cells
how are antibodies produced
by lymphocytes in response to antigens (anything foreign)
what is a monoclonal antibody
identical antibodies from a cloned white blood cell, meaning all the antibodies are identical and will only target one specific antigen
how to target one specific antigen
monoclonal antibodies
- inject mouse with antigen
- lymphocytes in mouse produce antibodies against antigen
- lymphocytes collected
- lymphocytes wont divide by mitosis, so fused with tumour cells, which divide lots
- hybridoma cell produced, one that contains wanted antibody selected
- divides by mitosis to get clones of identical cells, which will produce identical antibodies (monoclonal antibodies)
- antibodies collected and purified
uses of monoclonal antibodies and disadvantage
- accurate pregnancy tests that are cheap and easy to use
- measure hormone levels. blood sample taken and tested using monoclonal antibodies
- attach to dyes to locate or identify specific molecules in cell or tissue
- treating cancer. monoclonal antibodies made specific to cancer cells & attach toxic drug to stop mitosis. doesnt affect body cells
- harmful side effects
what do vaccines contain and why
Dead or weakened pathogens so it cannot lead to disease
What is a vaccination do?
Create immunity without making you sick
how do vaccinations work?
- dead or weakened pathogens injected into body
- WBC responds like normal, produces antibodies/antitoxins
-WBC divides via mitosis - copies stay in blood, can rapidly produce correct antibodies if live pathogen invades
what is herd immunity
vaccinating a large number of people, so those unvaccinated (migrated, missed when younger) cannot catch disease as no one can pass pathogen on
what drugs can be prescribed for disease and what are the negatives
painkillers - relieve symtpoms, do not kill pathogens
antibiotics - kill bacteria in body without damaging body cells. carefully prescribed as specific antibiotics kill specific pathogens.
- antibiotic resistance -> drug overused, bacteria evolves to withstand
why is it difficult to treat viruses
viruses live inside human body cells, difficult to kill without damaging tissue
name medicines and where they are extracted from
digitalis - foxglove
aspirin - willow
penicillin - the mould penicillium
what are drugs tested for?
efficacy, safety, dosage
what is the order of things that get tested on for medicine and drugs?
preclinical (non-human): Cells, tissues, animals, in lab
clinical (human): a few healthy people with low dose, healthy people to find optimal dose
how can you test how well a drug works
double blind trial:
patients randomly split:
- one group receive active drug
- one group receive placebo
- neither patients or doctors know who has taken what to stop bias of doctors monitoring active group
- doctor can see actual difference drug makes
- peer reviewed
how to pregnancy test work?
there is a hormone only found in pregnant women
there are antibodies to this hormone on the bit you wee on, with blue beads attached
the hormone binds to these antibodies/beads
moves up stick, carrying hormones/beads
there are more antibodies on the test strip that are stuck on
hormone binds to the antibodies on this strip, blue beads with it
strip turns blue
