biology b6 Flashcards
what is a disease?
a condition that is caused by any part of the body not functioning properly
what can diseases affect?
mental and physical health
what is a communicable disease?
diseases that can be spread between organisms
what is a non communicable disease?
diseases cannot be spread between organisms
what can cause communicable diseases?
most are caused by microorganisms (parasites)
when they enter the organism (pathogen)
what are causes of non communicable diseases?
poor diet
obesity/lack of exercise
genetic disorder
body processes not operating correctly
what does HIV do?
weakens a persons immuable system
what does HPV cause?
cervical cancer
how are pathogens spread between animals?
through cuts in skin
digestive system (when foods/drinks are shared)
respiratory system (inhaling pathogens)
reproductive system (sexual intercourse)
how can pathogens spread between plants?
vectors (insects)
direct contact of sap from an infected plant
wind (blown between plants)
how do pathogens cause diseases?
incubation period-
pathogens reproduce rapidly and as they grow, they cause cell damage and produces toxic waste products
how do viruses reproduce / ‘take over’ cells?
- virus attacks cell
- inserts it’s genes
- ‘tells’ nucleus to copy its genes
- new viruses are made
- cell bursts, releasing the new viruses, destroying more cells
what is the difference between vector and pathogen?
pathogen causes a disease
vectors spread the disease
what are the two types of white blood cells called?
lymphocytes
phagocytes
what do phagocytes do?
engulf the microorganisms then make enzymes that digest the microorganism
what do lymphocytes do?
make antitoxins or antibodies
what is a vaccination?
a dead/weakened pathogen that is inserted into the bloodstream.
Explain how vaccines work
- small amount of dead/weakened pathogen inserted into your body by injection
- antigens in the vaccine stimulate WBCs to make antibodies
- the antibodies destroy the antigens
- memory cells are then produced to prevent infections by responding quickly
how are pathogens killed?
antiseptics
antivirals
antibiotics
what do antiseptics do?
kill / neutralise all types of pathogens but do not damage human tissue. e.g iodine , alcohol
what do antivirals do?
drugs that destroy viruses by preventing them from replicating, treat infections
what does the antiviral drug do?
- blocking the virus from entering host cell
- prevents virus from releasing genetic material
- prevents virus from inserting its genetic data into host cells dna
what do antibiotics do?
drugs that kill bacteria without damaging cells
how do you identify the bacteria and which antibiotic to use?
doctors send blood / stool samples to a laboratory
scientists grow the bacteria on agar plates
they are treated with different antibiotics
the antibiotic that is the most effective is used on patient
how do you measure the zone of inhibition?
πr^2
how are new drugs discovered?
plant extracts
made in laboratory
computer modelling to develop drugs
what is preclinical testing?
drugs tested on cells and live bacteria before getting tested on living organisms
why do most drugs fail during preclinical testing?
the cells are damaged or do not work
what are the stages of developing new drugs?
1) drug tested on animals
2) drug tested on humans (clinical trial):
tested on healthy volunteers
tested on small sample of people with condition
tested on large number of people with condition
what is the clinical trial?
when the drug is tested on humans
what are the 3 stages of clinical trial?
-tested on healthy volunteers (see any unexpected side effects)
- tested on small amount of people who suffer from condition (see how effective drug is)
- tested on large number of people with condition (see how well it works and its safe)
what is the placebo effect?
when people feel better because they expect to feel better from taking a medicine
what is a double blind trial?
the real drug is given to some patients, while others get a harmless substance. neither the doctor or patient know are told if they have the drug or not
how do u prevent the spread of diseases?
- covering mouth when sneezing
- not touching infected people/objects
- use protection
- not sharing needles
- wash hands properly
- cook food properly
- drink clean water
- protect yourself from animal bites
what happens when farmers identify diseases?
- plant is burnt
- animals are treated using drugs /some may be slaughtered
- livestock cannot be removed
- chemical dips are installed on farms
how are diseases identified?
- changes in an organisms appearance
- identifying pathogen by its DNA or antigens (proteins on surface of microorganism)
what is athletes foot?
a fungal disease caused by a group of parasitic fungi called dermatophytes
what are the symptoms of athletes foot?
cracked, flaking, itchy skin
how can athletes foot spread?
direct contact (skin to skin)
indirect contact ( e.g touching same towel as contaminated fungus)
what is food poisoning?
caused by the growth of microorganisms in food
what are the common symptoms of food poisoning?
stomach pains
diarrhoea
vomiting
fever
what are STIs?
(sexually transmitted infections) are passed from one person to another through unprotected sex or genital contact
how do people protect themselves from STIs?
avoiding sexual intercourse
using condoms
what is a sample?
taking observations / measurements from a small area representing a larger area
how can you sample animals?
pooters
sweep nets
kick sampling
tree beating
pitfall traps
how to use pooters?
suck on mouthpiece to draw insects
a filter stops the organisms from entering mouth
how to use sweep nets?
sweet a large net through the air to catch flying insects
how to use kick sampling?
‘kick’ a river bank to disturb the mud and vegetation
hold net downstream to capture any organisms released into flowing water
how to use tree beating?
stretch a large white cloth under a tree
shake / beat tree release invertebrates which will fall onto the cloth
how to use pitfall traps?
dig a hole in the ground which drawing insects can fall into
cover hole with roof so it doesn’t fill with rainwater
what are two main types of identification keys?
branched key (spider key)
numbered key
how to capture population of animals?
- capture organisms from sample area
- mark individual organisms then release
- at later date, recapture organisms in same area
- record number of marked and unmarked individuals
- estimate population size
how to estimate population size
first sample size x second sample size
——————————————————
number of recaptured marked
what do you use to sample plants?
a quadrat
what is random sampling?
individuals are selected by chance
what is non random sampling?
study how distribution of organism varies over a distance, using a transect
how does a scab form?
- skin is cut and starts to bleed + leaks
- platelets change blood protein fibrinogen to fibrin
- RBCs are trapped in fibres forming a blood clot
- clot hardens to keep skin clean and give time to heal which eventually falls off
what lifestyle changes treat cardiovascular disease?
- eating less processed food
- exercising regularly
- reducing alcohol
- stop smoking
what surgery’s are involved to treat CVD?
- replacing damaged valves
- widening blocked arteries using a stent
- bypassing blocked arteries using other blood vessels
