Infection and Response

Question 1

How does bacteria make you feel ill?

Answer 1

By producing toxins that damage you cells and tissues

Question 2

How do viruses make you feel ill?

Answer 2

Get inside your cells and use the cell to make copies of themselves which eventually burst the cell and this damage makes you ill

Question 3

How do fungi cause disease?

Answer 3

They grow and penetrate the skin and then produce spores which can be spread

Question 4

What are the main ways that pathogens are spread?

Answer 4

-dirty water e.g. cholera
-breathed in the air e.g. influenza
-direct contact e.g. athlete’s foot

Question 5

What is measles?

Answer 5

-A virus spread by droplets from sneezing and coughing
-causes a red rash and fever
-can be serious and fatal e.g. lead to pnuemonia
-most are vaccinated young

Question 6

What is HIV? How is its replication controlled?

Answer 6

-virus spread by sex or sharing needles
-starts with flu like symptoms
-replication controlled with antiretroviral drugs
-attacks immune cells

Question 7

What is Tobacco Mosaic Virus (TMV)?

Answer 7

-virus in plants
-causes mosaic pattern on leaves, parts get discoloured
-hinders photosynthesis and growth

Question 8

What is Rose black spot? How is it spread and treated?

Answer 8

-fungus in roses
-causes purple or black spots on leaves and then they go yellow and drop off
-hinders photosynthesis and growth
-spread by water and wind
-treated with fungicides and by removing affected leaves

Question 9

What is Malaria? How can its spread be prevented?

Answer 9

-disease caused by protist
-spread by vectors (mosquitos)
-causes repeated fever episodes
-can be fatal
-spread can be reduced by stopping mosquitos from breeding
-can be prevented using insecticides and mosquito nets

Question 10

What is salmonella?

Answer 10

-bacteria that causes food poisoning
-causes D and V, fever, stomach cramps
-spread by contaminated foods

Question 11

What is gonorrhoea?

Answer 11

-STD cause by bacteria
-causes pain when urinating
-originally treated with anitibiotic penicillin but some strains have now become resistant
-prevented by using contraception

Question 12

How can we reduce and prevent the spread of disease?

Answer 12

-being hygenic
-destroying vectors
-isolating infected people
-vaccination

Question 13

What is the body’s line of defence against pathogens?

Answer 13

-skin -> barrier, secretes antimicrobial substances
-hairs and mucus in nose -> trap pathogens
-trachea and bronchi ->secret mucus to trap pathogens
-cilia -> waft mucus up into the throat to be swallowed
-stomach -> produces hydrochloric acid to kill pathogens

Question 14

What is the first stage of the immune system’s attack?

Answer 14

White blood cells engulf the pathogens. This is called phagocytosis.

Question 15

What is the second stage of the immune system’s attack?

Answer 15

White blood cells start to rapidly produce antibodies which attack onto the antigens of all the pathogens so they can be found and destroyed. Antitoxins are also produced to counteract the toxins from the bacteria.

Question 16

What is the third stage of the immune system’s attack?

Answer 16

Killer cells destroy the pathogen and memory cells are produced to remember how to fight that pathogen should the body become infected again.

Question 17

How do vaccines work?

Answer 17

Small amounts of dead or inactive pathogens are injected into the body, carrying antigens which cause the immune system to produce antibodies to combat them. This means that if live pathogens invade the future, the white blood cells already know how to deal with them.

Question 18

What are the pros and cons of vaccinations?

Answer 18

-controls and prevents outbreaks of viruses, reduces the cases of previously common viruses
-don’t always work, can sometimes cause bad reactions and side effects

Question 19

What are examples of drugs that reduce symptoms?

Answer 19

pain killers and cold medicines which relive pain and discomfort without actually tackling the pathogen

Question 20

Why can’t viruses be treated with medicine?

Answer 20

Because they get inside body cells which means it’s difficult to kill them without killing the body cells too

Question 21

What are examples of drugs that cure the problem?

Answer 21

Antibiotics like penicillin which kill or prevent the growth of the pathogen without affecting the body cells. Different antibiotics kill different bacteria.

Question 22

What does it mean if bacteria mutate to become antibiotic resistant? How is this prevented?

Answer 22

That they won’t be killed by antibiotics and the strain will continue to reproduce and spread. This is prevented by not over-prescribing antibiotics and finishing the whole course.

Question 23

What are some examples of drugs that come from plants?

Answer 23

-Aspirin -> developed from willow trees
-Digitalis -> developed from foxgloves

Question 24

What is an example of a drug that was developed from microorganisms?

Answer 24

Penicillin was discovered when it was found that a particular area of a petri dish that had grown mould was free from bacteria as it was producing a substance that killed it

Question 25

What is the first stage of drug testing?

Answer 25

The drugs are tested on human cells and tissues

Question 26

What is the second stage of drug testing?

Answer 26

Tested on live animals to test efficacy and toxicity and find the best dosage

Question 27

What is the third stage of drug testing?

Answer 27

Testing on human volunteers in a clinical trial.
-healthy volunteers -> test for side effects
-ill people -> find optimum dose
-split into two groups, one with placebo

Question 28

What are monoclonal antibodies?

Answer 28

Antibodies produced from a single group of genetically identical B-cells that only target one specific type of pathogen

Question 29

How are monoclonal antibodies made?

Answer 29

-Mouse injected with antigen
-the B-lymphocytes that the Mouse’s body produces are taken and fused with the tumour cell
-this makes a hybridoma
-it divides quickly to make lots of clones that produce the monoclonal antibodies

Question 30

How are monoclonal antibodies used?

Answer 30

-pregnancy tests
-measure levels of chemicals like hormones in the blood
-treating diseases like cancer

Question 31

What are the advanatges of monoclonal antibodies?

Answer 31

They can treat diseases like cancer with causing less side affects than other treatment because they target specific cells

Question 32

What are the disadvantages of monoclonal antibodies?

Answer 32

They cause more side affects than originally expected like vomiting, fever and low blood pressure so they used as widely as people thought

Question 33

What mineral ions do plants need and why?

Answer 33

-Nitrates -> to make protein for growth
-Magnesium ions -> to make chlorophyll for photosynthesis, preventing chlorosis

Question 34

What are the signs of a plant having a disease?

Answer 34

-stunted growth
-abnormal growths
-spots on leaves
-malformations
-rot
-discolouration

Question 35

What physical defences do plants have?

Answer 35

-waxy cuticle to act as a barrier
-cellulose cell walls
-layers of dead cells around stems (e.g.) tree bark)

Question 36

What chemical defences do plants have?

Answer 36

-producing antibacterial chemicals
-producing poisons to stop themselves from being eaten

Question 37

What mechanical defences do plants have?

Answer 37

-thorns and hairs to stop themselves from being eaten
-leaves droop or curl when touched to knock insects off of them
-Mimic other organisms to blend in