infection and response Flashcards
describe what a communicable disease is
a disease that is spread from person to person
example of a communicable disease
measles
communicable diseases are spread by pathogens:
bacteria or viruses
example of non communicable disease
coronary heart disease
define health
the state of mental and physical wellbeing
what else, other than disease, can ill health be caused by x3
stress
poor diet
other life situations eg working with harmful chemicals.
what is tb
a communicable lung disease, could be fatal
example of a condition that causes a defective immune system
HIV
what does hiv cause
causes a defective immune system
example of diseases trigered by the immune system x2
athma / dermatisis
what happens when the immune system triggers a disease
the immune system fights of the pathogen but the person is left with an allergy
name a physical illness that can lead to a mental one
arthiritis can lead to depression
define pathogen
a microorganism that cause infectious disease
how do bacteria make us ill (3 points)
r
r
d
reproduce rapidly in human body
release harmful toxins
these damage tissue.
making us feel ill
can viruses reproduce by themselves
no, only in a host cell
can bacteria reproduce by themselves
yes
how do viruses make us ill
3 points
i
r
d
virus invades host cell
reproduces in host cell
causing cell damage
eg( when leaving cell, can cause cell to burst and die)
3 ways pathogens are spread
in air
in water
direct contact
pathogen spread in air
influenza
pathogen spread in water
cholera- water polluted by sewage
pathogen spread by direct contact
HIV- druggies share infected needles + sexual contact
how to prevent spread of pathogen x5
basic hygeine
clean drinking water- contains chlorine in uk
reduce direct contact
isolation if infectious
vaccination
!!!!can viruses be killed by antibiotics. Why / why not
no
symptoms of measles x2
fever
red skin
how is the measle virus spread
The measles virus is spread by inhalation of droplets from sneezes and
coughs.
is measles serious disease. yes/ no/ why
Measles is a serious illness that can be fatal if complications arise.
can damage breathing system and brain
precaution to prevent the spread of measles
children vaccinated when young
symptom of HIV
flu like illness
how does hiv cause illness
virus attacks cells of immune system
damages immune system
person cant fight off any infections or cancers
describe late stage HIV
Late stage HIV infection, or AIDS, occurs when the body’s immune system
becomes so badly damaged it can no longer deal with other infections
or cancers
how can people with hiv be treated
(remember how hiv is spread+ iv)
with antiretroviral drugs
what do antiretroviral drugs do
stop virus multiplying
so immune system isnt damaged
are antiretroviral drugs a cure for HIV/ AIDS
no, must take them their whole life
how can HIV be spread
unprotected sex
share infected needles
example of viral disease x2
HIV
AIDS
can bacteria be killed by antibiotics
yes
how is salmonella food poisoning spread
spread by bacteria ingested in food
on food prepared in unhygienic conditions
what are symptoms of salmonella caused by
caused by the bacteria and the
toxins they secrete.
symptoms of salmonella x5
vfacd
Fever,
abdominal
cramps,
vomiting
diarrhoea
how is the spread of salmonella controled in uk
In the UK, poultry are
vaccinated against Salmonella to control the spread.
ghonorrea is a bacterial disease + an example of a …
STD
sexually transmitted disease
symptoms of gonorrhea
thick yellow or green discharge
from the vagina or penis
pain on urinating.
how was gonnorrhea treated in the past. Why not now?
was easily treated with the
antibiotic penicillin
until many resistant strains appeared
how to stop spread of gonorrhea
use barrier method
eg condom
treatment with antibiotics
eg people who have unprotected sex
is malaria communicable
yes
the malaria pathogen is an example of a ……
protist
symptom of malaria
repeated bouts of fever
describe life cycle of malaria
4 points
infected person bitten by mosquito
malaria pathogen passes into mosquito
bites someone else
passes malaria pathogen to them
mosquitoes are vectors. Why
carries pathogen from one person to another
how to stop spread of malaria
use mosquito nets
stop mosquitoes breeding
( drain still water as that’s where they breed)
2 main defence systems against pathogens
non specific defense system
immune system
job of non specific immune system
prevent pathogen entering the body
4 parts of non specific defence system
skin
nose
trachea and bronchi
stomach
how does skin defend against pathogens x4
forms a protective layer
outer layer- dead cells - pathogens struggle to penetrate
sebum kills bacteria
skin scabs over
how does nose defend against pathogens
contains hair and mucus
trap pathogens before they enter breathing system
how do the trachea and bronchi defend against pathogens
covered with tiny hair, Cillia
describe how pathogens go from bronchi/ trachea to stomach
mucus on cillia trap pathogens
cillia waft mucus up throat
which is swallowed into the stomach
how does stomach defend against pathogens
contains hydrochloric acid
which kills pathogens
2 main functions of immune system
destroy pathogens and toxins produced
protect from the same pathogen in future
what do white blood cells do
ingest and destroy pathogen
steps describing how WB cells destroy pathogen through phagocytosis
detect chemicals released by pathogen
move to it
ingests pathogen
wb cell uses enzymes to destroy pathogen
what are antibodies
protien molecules produced by white blood cells
how do antibodies destroy pathogens
3 points
antibodies are produced by lymphocytes
they target and help destroy specific pathogens
by binding to antigens on the pathogens surface
(the pathogens now start to clump together
making it easier for white blood cells to find them and destroy them)
what happens if your reinfected
3 points
if your re infected…
the antibodies are produced at a faster rate
the person wont feel symptoms
said to be immune
what do antitoxins do to defend against pathogens
they neutralise the toxins released by pathogens by binding to the toxins
what is TMV
tobacco mosaic virus is a widespread plant pathogen
example of plants tmv affects
many species eg tomatoes
what does tmv cause on leaves
leaves get distinctive mosaic pattern of discolouration
what does the discolouration from tmv cause
rate of photosynthesis reduced
and so plant growth rate reduced
2 infectious diseases in plants
rose black spot
tmv
what is rose black spot
a fungal disease in plants
rose black spot causes what on leaves
purple or black spots on leaves
turn yellow
or drop off early
what does the spots from rose black spot cause
reduction in photosynyhesis
reduces growth
how is rose black spot ( a fungal disease) spread
by water or wind
how to treat rose black spot
spray with fungicides (kill fungi)
remove and destroy infected leaves
what does vaccination involve
introducing small quantities of dead/ inactive forms of pathogen in to body
what does the small inactive pathogen in a vaccination cause
stimulates the white blood cells
to produce antibodies
what does the white blood cell do to prevent infection in the future
describe how this helps to prevent infection
wbc divides by mitosis
produces copies of itself
copies stay in body for years
if reinfected, wbc can produce correct antibodies quickly
preventing infection
what is herd immunity
if a large population is vaccinated, the disease is less likely to spread
even if there are some unvaccinated people
how does herd immunity protect unvaccinated people
the unvaccinated person cannot catch the disease because no one around them can pass the pathogen on
what are the two main types of white blood cells
lymphocytes
phagocytes
2 ways phagocytes fight pathogens
antitoxins
antibodies
describe vaccination in three steps
injecting a small quantity of dead/ inactive form of pathogen into body
lymphocytes stimulated to produce correct antibodies for the pathogen
if pathogen re-enters, correct antibodies produced quickly to prevent infection
first antibiotic discovered
penicillin
what do antibiotics do
cure bacterial disease by killing infective bacteria inside
the body
do antibiotics harm body cells
no
specific bacteria must be treated with …… ……
. It is important that specific bacteria should be
treated by specific antibiotics.
antibiotics have been overused. what has this caused
antibiotic resistance
certain antibiotics no longer effective against certain bacteria
what is antibiotic resistance
bacteria evolve, not killed by antibiotic
can antibiotics kill viruses
no
what do painkillers do
treat the symptoms of disease but do not kill pathogens.
why is it hard to create drugs that kill viruses
2 points
viruses live and reproduce inside human cells
It is difficult to develop drugs that kill viruses without also
damaging the body’s tissues.
name a drug extracted from a plant
name the plant also
Heart drug, digitallis,
extracted from Foxglove
name a painkiller extracted from tree
name the tree
painkiller aspirin
extracted from willow tree
penicillin was discovered by……
alexander fleming
how was penicillin discovered
from the penicillium mould
how are most new drugs made
synthesised by chemists in the pharmeceutical industry
what is the starting point for most drugs
a chemical extracted from a plant
three things new drugs are tested for
toxicity - is it harmful
efficacy- does it work
dosage- what amount is safe and effective to give
what must be done to new drugs before being used
New drugs to be tested and trialled before use to
check they are safe and effective.
1st stage of testing
preclinical testing
what is preclinical testing
testing carried out on
cells
tissues
live animals
what happens after pre clinical trials
clinical trials
what happens in clinical trials
2 steps
-super low doses to healthy volunteers -
check if drug i safe + effective
- if safe further clinical trials carried out to find the optimum dose
more volunteers
what is an optimum dose
best dose to treat disease with fewest side effects
what is a double blind trial.
patient and doctor don’t know who has real drug and who has
placebo
why are double blind trials used
reduces bias in the trial
in case doctor pay more attention to ppl receiving active drug
what is a placebo
tablet/ injection with no active drug in it
some people get better after a placebo . why
they think they are being treated
they believe they are going to get better
what happens after clinical trials
peer review
what happens in peer review
before publishing results
results of clinical trial tested and checked
by INDEPENDENT researchers
three stages of clinical trials
Pre-clinical
clinical
peer review
what does the graph for vaccination
( time on X axis and concentration of antibodies in blood on Y axis ) look like
before vaccination
0 antibodies
when vaccinated
amount antibodies rise and then fall but more then 0
when infected
The amount of antibodies spikes very high
then begins to decrease again
what do lymphocytes produce antibodies against
anything the body detects as foreign ( antigens)
how are monoclonal antibodies made
They are produced by stimulating mouse lymphocytes to make a particular antibody
2 ways antibodies are used
pregnancy testing kits
certain cancer treatments
steps of producing monoclonal antibody
6 steps
1) inject mouse with antigen
lymphocytes will produce antibodies against the antigen
2) collect lymphocytes from the mouse
lymphocytes dont divide by mitosis
3)fuse lymphocytes with tumour cells (very good at dividing by mitosis) = hybridoma
-they can produce antibodies and divide by mitosis
4) select a hybridoma cell that produces the antibodies you want
5) Single hybridoma cells are cloned to produce many identical cells that all produce the same
antibody.
6) A large amount of the antibody can be collected and purified for use
fill in the gaps
Monoclonal antibodies are produced by stimulating mouse …………. to make a
particular …….
The lymphocytes are combined with a ………. cell to make a …….. cell.
This cell (………) can both …… and make the …….. Single ……….. cells are cloned to produce many …….. cells that all produce the same…….
A large amount of the antibody can be ……. and …….
monoclonal antibodies are produced by stimulating mouse LYMPHOCYTES to make a
particular ANTIBODY.
The lymphocytes are combined with a TUMOUR cell to make a cell called a HYBRIDOMA cell.
This cell (HYBRIDOMA) can both DIVIDE and make the ANTIBODY.
Single HYBRIDOMA cells
are cloned to produce many IDENTICAL cells that all produce the same ANTIBODY.
A large amount of the antibody can be COLLECTED and PURIFIED
what are monoclonal antibodies made from
a single clone of hybridoma cella
monoclonal antibodies are specific to a single binding site on a specific protein antigen. What does this mean
they can be used to target specific chemicals or cells
how are monoclonal antibodies used in pregnancy testing
to detect HCG which is produced by pregnant women and found in their urine
(HCG is produced by the placenta of the developing fetus)
pros of pregnancy tests w/ monoclonal antibodies
cheap
easy to use
highly accurate
(if correctly used)
4 uses of monoclonal antibodies
- DIAGNOSIS eg in pregnancy tests
- LABORATORIES -
measure level of hormones/ chemicals in blood + detect pathogens
*RESEARCH to locate / identify specific molecules in a cell or tissue
*TREAT DISEASES - eg cancer
how are monoclonal antibodies used in labs
-measure hormone level in blood
(tired/ lack energy- may have certain low hormones)
- detect pathogens in blood
what is an advantage of monoclonal antibody’s being used in labs to locate/ measure hormones or pathogens
they are completely specific to what you are looking for
how are monoclonal antibodies used:
to locate or identify specific molecules in a cell or tissue
monoclonal antibody attatched to fluorecsent dye
they bind to specific molecules
we can see where these are
how are monoclonal antibodies used to treat specific diseases eg cancer
4 points
(cancer cells undergo uncontrolled mitosis)
- antibodies made specific to cancer cells
- radioactive substance/ drug attached to antibody
- antibody attaches to cancer cells
- the radioactive substance or toxic drug stops cancer cell from dividing
pros of using monoclonal antibodies for treating diseases
antibody delivers substance directly to cell
without harming other cells
problem with monoclonal antibodies
create more side effects than expected and so not widely used
name a viral plant disease
tmv
name a fungal plant disease
rose black spot
aphids can attack plants. What do aphids do
aphids extract nutrients (eg sugar) from plant, stunting growth.
do insects count as pathogens. Why
no, as they dont cause an infectious disease
7 ways Plant diseases can be detected
- stunted growth
- spots on leaves
- areas of decay (rot)
- growths
- malformed stems or leaves
- discolouration
- the presence of pests.
3 ways to identify plant disease
- gardening manual or website
- take infected plants to laboratory to identify the pathogen
- use testing kits that contains monoclonal antibodies.
2 plant ion deficiency diseases
lack of nitrate ion
lack of magnesium ion
what does a lack of nitrate ion in plants cause
stunted growth
what does a lack of nitrate ion in plants cause
stunted growth
why does a lack of nitrate ion cause stunted plant growth
because nitrate is needed for protein synthesis and therefore growth
what does a lack of magnesium ion in plants cause
causes condition chlorosis - leaves lose green colour
why does a lack of magnesium ions cause chlorosis
because magnesium is needed to make chlorophyll
plants physical responses against attack x3
- Cellulose cell walls.
- Tough waxy cuticle on leaves.
- Layers of dead cells around stems (bark on trees) which fall off
plants chemical responses against attack x2
Chemical plant defence responses.
* Antibacterial chemicals.
* Poisons to deter herbivores.
plants mechanical adaptations.
- Thorns and hairs deter animals.
- Leaves which droop or curl when touched.
- Mimicry to trick animals.
how does the cellulose cell wall defend against attack
difficult for microorganisms to penetrate
how does the waxy cuticle (thin oily layer) defend against attack
difficult for microorganisms to penetrate- defends against attack
how does the bark defend against attack
bark is a barrier to entry for microorganisms
how does antibacterial chemicals defend against attack
kill bacteria and prevent them from entering the plant
how does poisons defend against attack
deter herbivores from grazing on the plant
how does the thorns/ hairs defend against attack
stop it being eaten
irritating/ difficult to eat
how do leaves that curl when touched defend against attack
scare herbivores
how does plants mimicry defend against attack
give example.
tricks animals
eg dead white nettle has no sting
looks like a stinging nettle
