infection and response ✅ topic 3 Flashcards
What are considered microorganisms?
Bacteria
Fungi
Viruses
Protists
What is a pathogen
A microorganism that can cause disease
What are the four main ways pathogens are spread
• Through the air - influenza through tiny droplets of saliva that we expel when we cough or sneeze
• Contaminated water - cholera spread through water sources contaminated by diarrhoea
• contaminated food - diseases such as salmonella
• direct contact - athletes foot walking bare foot on surfaces contaminated by fungi
Give three ways we can reduce the spread of infectious disease
• Vaccination
• Killing the vectors that carry pathogens
• Isolating
• Improved hygiene
TRUE OR FALSE viruses are living organisms
FALSE
TRUE OR FALSE viruses are made of cells
NO
Explain how viruses spread and multiply
1) Viruses can pass between humans via the air, contaminated food and water or direct contact
2) They can’t produce themselves, viruses have to enter one of our cells and then use it to create multiple copies of the virus itself
3) Once there are lots of copies, the viruses cause the cell to burst and then go on to infect neighbouring cells
How can measles be spread between people?
Via droplets in air when an infected person coughs or sneezes
What are the symptoms or measles
Red skin rash
Fever
Which two ways can HIV be spread between people
Sexual Contact
Exchange of bodily fluids
What can an infection with HIV virus lead to
AIDS
What is the treatment for HIV/AIDS
Antiretroviral drugs
this stops the virus from multiplying inside patient, does not damage immune system
What organisms does Tobacco Mosaic Virus infect
PLANTS
What is the main symptom of TMV
Patches of leaves get discoloured
TMV reduces the amount of photosynthesis that a plant can do
what are the consequences of this ?
• The plants won’t be able to grow as well
• The plant won’t be able to produce as many sugars
What are the small proteins that bacteria releases that damage cells
TOXINS
What is salmonella (1)
bacterial disease spread by consuming contaminated food
What are the symptoms of salmonella
Fever, Vomiting, Diarrhoea, Stomach cramps
What are the symptoms do gonorrhea? (STD)
Pain when urinating
Yellow/green discharge from the vagina or penis
How can you prevent the spread of gonorrhoea
avoid unsafe sex
use a condom
tested for gonorrhoea
What is the treatment for gonorrhoea
Antibiotics such as penicillin
What are examples eukaryotic organisms ?
Plants
Fungi
Animals
Proctists
Explain Rose Black spot (3)
Rose black spot is a fungal disease that causes purple or black spots develop on leaves, which then often turn yellow and drop off.
This reduces photosynthesis and so also reduces the growth of the plant
It can b spread by water or the wind
Treatment involves spraying the infected plants with fungicides or destroying the affected leaves
Protists are transported between hosts by
VECTORS (a mosquito that carries pathogen from one person to another)
Explain Malaria (communicable)
The organisms that cause malaria are a type of protist
They are transported between hosts by mosquitoes
The symptoms include fevers and headaches
How can we reduce the spread of malaria ?
• stop breeding of mosquitos drain still water areas
• Use mosquito nets
• Kill mosquito with insecticides
What are the following that act as barriers to reduce the entry of pathogens
• Skin
• Hairs in the nose
• Enzymes in tears
How does skin help to defend against disease
• It secretes oils and anti microbial substances that kill pathogens
• the outer layer of the skin consists of dead cells and is difficult for pathogens to penetrate
What are the hairs in the nose coated with to catch pathogens
Mucus
what are the tiny hair like projections that waft the mucus and pathogens away from the lungs
CILIA (trachea and bronchi)
What is the role of the immune system
To locate and destroy pathogens and any toxins they produce
What are the functions of the white blood cells (3)
PHAGOCYTOSIS
Produce antitoxins
producing antibodies
Explain stages of phagocytosis
1) Phagocytosis is carried out by a phagocyte
2) First step for phagocyte is to track down pathogen and the chemicals they release and bind to it
3) The phagocytes membrane will surround the pathogen and engulf it
4) enzymes inside the phagocyte break down the pathogen in order to destroy ur
What do anti toxins do
Bind and neutralise the toxins produced by bacteria
A vaccine can protect humans from a viral disease What does the vaccine contain
dead or inactive pathogen
Explain why a high level of TMV infection reduces growth in a plant (2)
As the level of infection of TMV increases the rate of photosynthesis decreases
this means less chlorophyll so results in less glucose being made
One type of microorganisms that can cause disease in human
bacteria , fungi , protist
ANTIBIOTICS DO NOT
kill VIRUSES
What are the two uses of glucose in a gorse plant
Respiration
to store as starch
Why are nitrate ions needs in plants
Nitrate ions are needed to make proteins / amino acids
which are needed for growth
What are the tablets made from sugar called
Placebos
What type of pathogen cause malaria
PROTIST
Describe how the human body
• prevents pathogens from entring
• defends itself against pathogens inside the body (6)
preventing pathogen from entering
- skin acts as a barrier (oil on skin repels pathogens)
- stomach contains HCL which kills the bacteria in food
- eyes produce tears which contains enzymes to kill bacteria , tears are antiseptic
- nose produces mucus , mucus is sticky, mucus traps bacteria, mucus carried away by cilia
DEFENCE INSIDE THE BODY
• immune system / white blood cells
white blood cells engulf pathogens
antitoxins are produced
• antitoxins neutralise toxins which are produced by pathogen
• antibodies produced
• antibodies destroy pathogens
• memory cells are formed
what is TB
communicable lung disease
What happens to people with defective immune systems
more likely to suffer from infectious diseases
How can bacteria make us ill
They release toxins
Toxins damage tissues and make us feel ill 
How can viruses reproduce
in a host cell
Explain the life cycle of malaria
first the infected person is bitten by a mosquito. The malaria pathogen passes into the mosquito.
The mosquito now bites a different person and passes the malaria pathogen to them
How does stomach protect us from pathogens
Stomach contains hydrochloric acid
this kills pathogens before they get any further
Explain the factors antibodies
• protein molecules produced by white blood cell
• antibodies stick to pathogens
• triggers pathogen to be destroyed
how can rose black spot be spread
water or wind
How can rose black spot be treated
spray plant with fungicides
remove infectious leaves then destroy them
Explain vaccination
• Involves introducing small amounts of dead or inactive forms of a pathogen into the body
• white blood cells are stimulated to produce antibodies against the dead pathogen
• white blood cells divide by mitosis
who discovered pencillin
alexander flemming
How are drugs tested and trialled (3)
1) first test toxicity of drug
2) check if drug is effective
3) work out the dosage
Explain the stages of drug testing
1) preclinical testing on cells, tissues od animals
2) clinical testing in humans - very low doses given to healthy humans
define placebo
a tablet or injection with no active drug in it
Explain a double blind trial
The test group receive the active drug
the placebo group receive a dummy drug with no active ingredient
neither patients or doctors know which people are receiving each drug
to stop bias
What are antibodies produced by
white blood cells called lymphocytes
what are foreign objects
antigens
What is the process of obtaining monoclonal antibodies
• When injected with an antigen the lymphocytes will produce antibodies against the antigen
• Then collect the lymphocytes from the mouse
• Join the lymphocytes with a tumour cell (mitosis)
• The cell produced is called hybridoma
• Hybridoma cells produce antibodies
• Select hybridoma cell and allow to divide by mitosis to form a clone of identical hybridoma cells
• These are called monoclonal antibodies
An advantage of monoclonal antibodies
they can target a specific chemical/cells in the body
What are the uses of monoclonal antibodies (5)
• pregnancy testing
• identify effects of pathogens
• locate blood clots
• treating some cancers
•to identify other hormones
How aphids affect plants
Aphids extract sugars from the phloem , not enough glucose to make proteins for growth
How to identify plant disease
garden manual or website
lab testing
What are the two examples of plant ion deficiency
•a lack of nitrate ion causes stunted growth because nitrate is needed for protein synthesis and therefore growth
• a lack of magnesium ion can cause chlorosis because magnesium is required to make chlorophyll
Explain plant defence - physical response (born with it)
•all plants have a cell wall
this is difficult for microorganisms to penetrate
• leaves are covered in waxy circle difficult for microorganisms to penetrate which protects plants from attack
• bark is a barrier to microorganisms
Explain plant defence - chemical response
• plants can release antibacterial chemicals which kill bacteria
• plants release poisons to deter herbivores from grazing on the plant
Explain plant defence - mechanical defence (3)
• Sharp thorns prevent eaten by a herbivore
• hairs that irritate mouth of herbivores
• mimicry - easily mistake white nettle for stinging nettle
Antibiotics only
are effective against bacterial pathogens
hybridoma cells can…
divide continuously this means they can produces monoclonal antibodies on a large scale
Two uses of monoclonal antibodies in cancer
• They bind to receptors of cancer cells preventing them from growing
• They signal to the immune system to destroy the cancer cells
why are new MABS made from humans more successful than MABS made form mice
the body is less likely to reject the Mabs
describe how injecting a monoclonal antibody for RSV helps to treat a patient suffering with the disease
• white blood cells engulf the virus
• monoclonal antibodies binds to the virus
Why are some people giving a placebo
to compare the effects of the treatment vs no treatment
Explain how the pregnancy test strip works to show a positive result
as urine passes through the reaction zone
HCG hormone binds to the mobile HCG antibody
HCG binds to the immobilised HCG antibodies in the result zone
other antibodies do not attach to HCG
bind to antibiotics in control zone
blue dye appears in both control and result zones
Define Translocation
Transporting dissolved sugars around plants
Explain one way the removal of dissolved sugars from the stem of the plant causes stunted growth
Less sugars for respiration so less protein produced
Explain how the production of oils on the surface of the leaf may protect plants from aphids
oils prevent aphids from attaching to the leaf (slide off)
