B1c - staying healthy

Question 1

what is the meaning of parasite (with reference to malaria)(2)

Answer 1

an organism that lives off another organism

the protozoan is the parasite in malaria

Question 2

what is the meaning of host (with reference to malaria)(2)

Answer 2

The organism which a parasite is living off of

The human is the host in malaria

Question 3

Explain how knowledge of the life cycle of mosquitoes can help control infections(3)

Answer 3

The areas of water where mosquitoes lay their eggs can be drained/sprayed with insecticides

Fish can be introduced into the water to eat mosquito larvae

People can be protected from mosquitoes using insecticides/mosquito net

Question 4

How do vectors spread the disease(4)

Answer 4

Vector - carry the disease without getting it themselves

Mosquitoes are vectors

They pick up the malarial parasite when they feed on an infected animal

Every time the mosquito feeds on another animal it infects it by inserting the parasite into the animal’s blood vessels

Question 5

Describe how changes in lifestyle and diet which may reduce the risk of some cancers(3)

Answer 5

Not smoking reduces your chances of getting lung cancer

Eating less processed meat and more fibre may reduce your risk of getting colon cancer

Using sunscreen reduces the risk of skin cancer

Question 6

Describe benign tumour(3)

Answer 6

The tumour grows until there’s no more room.

The cells stay where they are.

This type isn’t normally dangerous

Question 7

Describe malignant tumour(2)

Answer 7

This is where the tumour grows and can spread to other sites in the body

Malignant tumours are dangerous and can be fatal

Question 8

Explain how pathogens cause the symptoms of an infectious disease

Answer 8

by cell damage or by toxins produced by the pathogens

Question 9

Why are different antibodies needed for different pathogens(2)

Answer 9

Each pathogen has its own antigens, so specific antibodies are needed

Antibody produced to have a complementary fit with the antigen

Question 10

Explain the difference between passive and active immunity(6)

Answer 10

Active immunity - Immune system makes its own antibodies after being stimulated by a pathogen

• usually permanent
• slow process

Passive immunity - use antibodies made by another organism

• only temporary
• effect is immediate

Question 11

Explain the process of immunisation (vaccination)(4)

Answer 11

1. Harmless pathogen given which carries antigens
2. Antigens trigger immune response by white blood cells which produce antibodies
3. Antibodies lock on to antigens leading to the death of pathogens
4. Memory cells produced and remain in the body, providing long lasting immunity to that disease

Question 12

Benefits of immunisation(2)

Answer 12

Stops you from getting ill

Disease won’t be able to spread as easily if most people are immunised

Question 13

Risks of immunisation(2)

Answer 13

Can have short-term side effects, such as swelling and redness at the site of injection

You can’t have some vaccines if you’re already ill, especially if your immune system is weakened

Question 14

Describe how pathogens that enter the body are destroyed by the immune system (white blood cells)(3)

Answer 14

White blood cells travel around in your blood and crawl into every part of you, constantly patrolling for pathogens

Pathogen engulfed by white blood cells

Antibodies lock on to the antigens on the surface of pathogens, leading to the death of the pathogens

Question 15

Why are new medical drugs tested?(2)

Answer 15

To make sure they work

To make sure they are safe to use

Question 16

How are new treatments tested and understand objections to some forms of testing(6)

Answer 16

Computer models - stimulate a human’s response to a drug, but not as accurate as actually seeing effect on live organism

Then testing on human tissues - cant use human tissue to test drugs that affect whole/multiple body systems

Animal testing is final stage- Some think it’s cruel, others think it’s safest way to make sure a drug isn’t dangerous before given to humans

Question 17

Explain why blind and double blind trials are used(5)

Answer 17

Placebo is a harmless pill - often used to assess the effect of a new drug

Blind - patient in the study doesn’t know whether they’re getting the drug or the placebo

Double blind - neither patient no scientist knows until after

These trials avoid biased opinions

Sometimes existing treatments are used instead of a placebo - this tells them how well the new drug compares to what we already have