infection and response Flashcards
what is a pathogen
microorganisms that can cause disease
give ways to reduce the spread of infectious disease
-Improved hygiene, such as washing hands and cleaning surfaces
-Vaccination
-Killing the vectors that carry pathogens
-Isolating or quarantining people who are infected
give 3 viruses and the symptoms
-measels
red rash, fever, can be fatal
-hiv
fever, tiredness, then gets better and damages immune system, AIDS
-tobacco mosaic virus
-affects tobacco & tomato plants
-discolors patches on leaves, photosynthesis wont happen here
what is used for aids
antiretroviral drugs
-prevents virus replicating
-used early on, normal life
symptoms of salmonella bacteria
infects intestines
-fever
-vomiting
-diarrhoea
-fever
-stomach cramps
gonorrhea symptoms
and treatment and prevention
pain when urinating
green/yellow discharge
treatment: penicillin, now there’s resistant strains so have to use rarer and more expensive ones
prevention: avoiding unprotected sex
Bacteria release small proteins called _________. These can damage our cells and are responsible for many of the symptoms of bacterial diseases.
toxins
fungi and protists can be ….cellular and ….cellular
and are …… organisms
uni and multi
eukaryotic
describe RBS disease
what happens to the leaves
how spreads
treatment
-rose black spot, fungal disease
leaves can start to turn yellow and drop off
spreads by the water, wind
treatment: chop off infected leaves (then destroy so fungi can’t spread to other plants), spray plant with fungicide
parasites:
-live on or inside another organism
survive at the other orgs expense
-transported by vectors (eg mosquitoes)
who don’t get the disease themselves
eg. malaria, needs human host to survive, trans by mosquitoes
-prevention: moshari, killing vectors and destroying their breeding places
protists are ….. celled …….
single celled eukaryotes
name the viral, fungal, protists, and bacterial diseases
viral
-measles, HIV, tobacco mosaic virus
fungal
-rose black spot
protist
-malaria
bacterial
-salmonella, gonorrhea
describe the bodies physical defenses against pathogens:
-skin
secretes oils and antimicrobial substances that kills pathogens
-nose
hairs and mucus trap pathogens
-trachea and bronchi
secrete mucus that trap pathogens, cilia waft them up to back of throat, swallowed
-stomach
produces HCl, kills most pathogens
how does immune system keep us healthy
WHITE BLOOD CELLS
-when they find foreign cells, they bind to them and engulf and digests them- PHAGOCYTOSIS
-produces antibodies
every invading pathogen has antigens on surface, wbc comes across one and starts producing antibodies, lock on to antigens, other wbc can find and destroy them
antibodies prod. rapidly, travel around body and find similar pathogens
if person infected again, antibodies rapidly produced
-produces antitoxins
counteract toxins produced by invading bacteria
how do vaccines work
-dead or inactive version of pathogens we want to be immune to inside vaccine
-still same antigens, so body responds by producing antibodies for the pathogen
-now body will have immunity as next time antibodies will be rapidly produced
pros and cons of vaccines
PROS
-protection from diseases
-prevent big outbreaks of diseases
-herd immunity
CONS
-don’t always give full immunity
-bad reactions to vacc
-can cause fevers, seizures, very rare
why don’t antibiotics work on viruses
-antibiotics made specifically for bacteria
-antibiotics wouldn’t be able to find them as viruses hide in body cells, and impossible to kill virus w/o killing body cell
What is a pathogen?
A microorganism that causes disease
aspirin originated from
bark of willow trees
digitalis used to treat heart problems originated from
chemicals in foxgloves
who discovered penicillin
alexander fleming
what is efficacy, toxicity and dosage
-how well drug works
-how harmful/ side effects of drug
-how much of drug/ concentration should be given
describe the stages in drug testing
-STAGE 1, drug tested on human cells/ tissues
pro - cheaply test tons of substances
con -doesn’t tell us the effects on entire organ / organism
-STAGE 2, testing on live mammals
these two stages are preclinical
-STAGE 3, clinical, give to healthy volunteers, low dosage, increasing gradually to check max dosage w/o side effects
-then given to sufferers, slowly inc. for optimum dosage, max efficacy, min toxicity
then double blind trialed, results written up and peer reviewed
Why is it important for medical trials to be double-blind?
To avoid any bias by the patients and/or researchers
If patients know they received the drug they may be more likely to report side effects
If researchers know who has been given the real drug then they may pay closer attention to those patients
what are b-lymphocyte cells
a type of wbc
describe how monoclonal antibodies are made
-inject mouse with antigen we want antibody to bind to, prod lots of b-cells
-needs lots of b-cells, but they don’t div quick enough so
-b-cells combined w/ fast dividing tumour cells, fuse and form hybridoma
-these prod antibodies but also divide rapidly
-left to divide in a petri dish, collected and purified
What are monoclonal antibodies?
Antibodies made from clones of a single type of cell
what hormone do pregnancy tests detect for
hCG
how do pregnancy tests work
-test strip: one side has antibodies to hCG stuck to it, other side has blue beads with antibodies stuck to it, but are free to move
-if preggo, peeing on the blue beads will make the antibodies bind to hCG,
liquid makes them wash off across the other side, gets stuck on other antibodies and turns strip blue
-if not preggo, blue beads just wash off
what can be bound to the end of a mono antibody to treat cancer
-toxic drugs
-radioactive substance
-a chemical to stop it growing and dividing
plants need nitrates for
-making proteins for growth
lack of causes stunted growth
plants need magnesium for
-making chlorophyll, to photosynthesise
lack of causes chlorosis, yellow leaves
state the physical, chemical and mechanical defenses of a plant
PHYSICAL
-waxy cuticle, cellulose (cell walls), layers of dead cells (bark)
CHEMICAL
-antimicrobials, poisons
MECHANICAL
-thorns and hairs, leaves that curl of droops when insects land on them
Magnesium deficiency symptoms include:
* yellow leaves
* stunted growth.
Explain how a deficiency of magnesium could cause these symptoms.
[5 marks]
yellow leaves due to lack of chlorophyll
so
less light absorbed (by chloro)
so
lower rate of photosynthesis
so
plant makes less glucose
so
plant converts less glucose into protein (for growth)
Explain why a high level of TMV infection reduces growth in a plant.
less chlorophyll
less glucose made
how do plants and fungi defend themselves from pathogen?
PLANTS
cell wall: tough / difficult to penetrate
waxy cuticle: tough / difficult to penetrate
dead cells /bark: fall off, taking pathogens with them
production of antibacterial chemicals kill bacteria
FUNGI
antibiotic production kill bacteria
bind fluorescent dye to…
mAbs
what main things do you test for in the first two stages of clinical testing?
- toxicity
- dosage
- efficacy
Scientists can produce monoclonal antibodies using mice.
The first step is to inject the virus into a mouse.
Describe the remaining steps in the procedure to produce monoclonal
antibodies.
stimulate (mouse) lymphocytes to produce antibody
(create a) hybridoma
* clone (hybridoma) cell
* (hybridoma) divides rapidly and produces the antibody
Why were some patients given a placebo?
as a control
