SB5

Question 1

What is health?

Answer 1

A state of complete physical, mental and social well-being, and not merely the absence of disease or infirmity.

Question 2

What are the two types of disease?

Answer 2

Communicable

Non-communicable

Question 3

What are communicable diseases?

Answer 3

Diseases that can be spread between individuals.

Question 4

What are non-communicable diseases?

Answer 4

Diseases that can t be transmitted between individuals

E.g - cancer and heart disease.

Question 5

What are pathogens?

Answer 5

Organisms such as viruses, bacteria, fungi and protists that cause communicable diseases.

Question 6

What do viruses have to do to reproduce?

Answer 6

They have to infect living cells - host cells.

Specific types of viruses will only infect specific cells.

Question 7

What happens at the start of the life cycle of a virus?

Answer 7

It starts when it infects a new host cell.

Many will then reproduce by the lytic pathway, but some can enter the lysogenic pathway first.

Question 8

What is the lytic pathway?

Answer 8

1. The virus attaches itself to a specific host cell and injects its genetic material into the cell.
2. The virus uses proteins and enzymes in the host cell to replicate its genetic material and produce the components of new viruses.
3. The viral components assemble.
4. The host cell splits open, releasing the new viruses, which infect more cells.

Question 9

What is the lysogenic pathway?

Answer 9

1. The injected genetic material is incorporated into the genome (DNA) of the host cell.
2. The viral genetic material gets replicated along with the host DNA every time the host cell divides - but the virus is dormant and no new viruses are made.
3. Eventually a trigger (e.g - a chemical) causes the viral genetic material to leave the genome and enter the lytic pathway.

Question 10

What is chlamydia?

Answer 10

1. Its a kind of bacterium, but it behaves in a similar way to a virus because it can only reproduce inside host cells.
2. Although it’s doesn’t always cause symptoms it can result in infertility.

Question 11

How can the spread chlamydia be reduced?

Answer 11

Condoms
Screening individuals
Avoiding sexual intercourse

Question 12

What is HIV?

Answer 12

Human Immunodeficiency virus.
It kills white blood cells, which are important to the immune response.

It can eventually lead to AIDS (Acquired Immune Deficiency Syndrome).

Question 13

What happens when a person gets AID?

Answer 13

The infected persons immune system deteriorates and eventually fails, because of this, the person becomes very vulnerable to infections by other pathogens.

Question 14

How do you prevent the spread of HIV?

Answer 14

It’s spread through bodily fluids.

One of the main ways is to use a condom.
Drug users should avoid sharing needles.
Medication can reduce the risk of an infected individual passing the virus on to others during sex. (Or a mother to her baby during pregnancy).

Question 15

What are the physical defences plants have against pathogens and pests?

Answer 15

Most leaves and stems have a waxy cuticle, which provide a barrier to stop pathogens entering them or pests form damaging them. It may also stop water collecting on the leaf, which could reduce the risk o infection by pathogens that are transferred between plants in water.

Plant cells themselves are surrounded by cell walls made form cellulose. These form a physical barrier against pathogens that make it past the way cuticle.

Question 16

What are the chemical defences plants have against pathogens and pests?

Answer 16

For example antiseptics, which kill bacterial and fungal pathogens.
They also produce chemicals to deter pests from feeding on their leaves.

Some of the chemicals can be used as drugs to treat humans.

Question 17

What are some example of plant chemicals being used in medicine?

Answer 17

Quinine comes from the bark of the cinchona tree. For years it was the main treatment for malaria.

Aspirin is used to relieve pain and fever. It was developed from a chemical ground in the bark and leaves of willow trees.

Question 18

What are some physical barriers on humans that try to stop pathogens entering the body?

Answer 18

1. The skin - if it gets damaged, blood clots quickly seal cuts to keep microorganisms out.
2. Hair and mucus in your nose trap particles that could contain pathogens.

Question 19

What are some chemical barriers in humans that try to stop pathogens entering the body?

Answer 19

The stomach produces hydrochloric acid. This kills most pathogens that are swallowed.

The eyes produce a chemical called lysozyme (in tears) which kills bacteria on the surface of the eye.

Question 20

What happens if a pathogen gets into your body?

Answer 20

Your immune system kicks in to destroy them.

The most important part is the white blood cells.

Question 21

What are B-lymphocytes?

Answer 21

A type of white blood cell that are involved in the specific immune response

Question 22

How do B-lymphocytes work?

Answer 22

1. Every pathogen has unique molecules (proteins) on its surface called antigens.
2. When your B-lymphocytes come across an antigen on a pathogen, they start to produce proteins called antibodies.
   Antibodies bind to the new invading pathogen, so it can be found and destroyed by other white blood cells.
   The antibodies produced are specific to that pathogen.
3. The antibodies are then produced rapidly and flow all round the body to find all similar pathogens.

Question 23

What do memory lymphocytes do?

Answer 23

Give immunity to later infection.

Question 24

What does immunisation do?

Answer 24

Stops you getting infections.

Question 25

How does immunisation work?

Answer 25

Usually involves injecting dead or inactive pathogens into the body. These are antigenic (they carry antigens), so even though they’re harmless your body makes antibodies to help destroy them. The antigens also trigger memory lymphocytes to be made.

Question 26

What are the pros of immunisation?

Answer 26

1. Big outbreaks of diseases, called epidemics, can be prevented if a large percentage of the population are immunised. 2. Some diseases, e.g- smallpox, have been virtually wipe out by immunisation programmes.

Question 27

What are the cons of immunisation?

Answer 27

1. Doesn’t always work - sometimes it doesn’t give you immunity. 2. You can sometimes have a bad reaction to a vaccine (e.g - swelling, or maybe something more serious like a fever or seizures). But bad reactions are rare.

Question 28

What are monoclonal antibodies?

Answer 28

Identical antibodies.

Question 29

How are monoclonal antibodies produced?

Answer 29

They’re produced from lots of clones of a single B-lymphocyte. This means all the antibodies are identical and will only target one specific protein antigen.

Question 30

Why can you make monoclonal antibodies that target cancer cells?

Answer 30

Cancer cells have proteins on their cell membranes that aren’t found on normal body cells. They’re called tumour markers. In the lab, you can make monoclonal antibodies that will bind to these tumour markers. They can be used to help diagnose and treat cancer.

Question 31

How are monoclonal antibodies used to diagnose cancer?

Answer 31

1. First, the antibodies are labelled with a radioactive element. 2. Then, the labelled antibodies are given to a patient through a drip. They go into the blood and are carried around the body. 3. When the antibodies come into contact with the cancer cells they bind to the tumour markers. 4. A picture of the patients body is taken using a special camera that detects radioactivity. Anywhere there are cancer cells will show up as a bright spot. 5. Doctors can see exactly where the cancer is, what size it is, and find out if it is spreading.

Question 32

How are monoclonal antibodies used to help treat cancer?

Answer 32

1. An anti-cancer drug is attached to monoclonal antibodies. 2. The antibodies are given to the patient through a drip. 3. The antibodies target specific cells (cancer cells) because they only bind to the tumour markers. 4. The drug kills the cancer cells but doesn’t kill any normal body cells near the tumour. 5. Other cancer treatments (like other drugs and radiotherapy) can affect normal body cells as well as killing cancer cells. 6. So the side effects of an antibody-based drug are lower than for other drugs or radiotherapy.

Question 33

How are monoclonal antibodies used to find blood clots?

Answer 33

1. When blood clots, proteins in the blood join together to form a solid mesh. 2. Monoclonal antibodies have been developed that bind to these proteins. 3. You can attach a radioactive element to these antibodies. 4. Then, if you inject them into the body and take a picture using a camera that picks up the radiation, that picture will have a really bright spot where there is a clot. 5. This means you can easily find a potential harmful clot and remove it.

Question 34

What are antibiotics used for?

Answer 34

Used to treat bacterial infections.

Question 35

How do antibiotics work?

Answer 35

They work by inhibiting processes in bacterial cells, but not in the host organism. For example, some antibiotics inhibit the building of bacterial cells walls - this prevents them from dividing, and eventually kills them.

Question 36

What are the stages of testing a potentially new drug?

Answer 36

Preclinical Clinical

Question 37

What happens in preclinical testing?

Answer 37

1. In preclinical testing, drugs are first tested on human cells and tissue in the lab. However, you can’t use human cells and tissues to test drugs that affect whole or multiple body systems. 2. The next step is to test the drug on live animals. This is to test that the drug works, to find out how toxic it is and to find the best dosage.

Question 38

What happens in clinical testing?

Answer 38

1. If the drug passes the tests on animals then it’s tested on human volunteers in a clinical trial. 2. First, the drug is tested on healthy volunteers to make sure that it doesn’t have any harmful side effects when the body is working normally. 3. If the results of the tests on healthy volunteers are good, the drugs can be tested on people suffering from the illness. The optimum dose is found 4. Patients are randomly put int two groups. One is given the new drug, the other is given a placebo. This is to allow for the placebo effect. 5. Clinical trails are blind - the patient in the study doesn’t know whether they’re getting the drug or the placebo. In fact, they’re often double-blind (neither patient or doctor knows). This is so the doctors monitoring the patients and analysing the results aren’t subconsciously influenced by their knowledge.

Question 39

What is a placebo?

Answer 39

A substance that looks like the drug being tested but doesn’t do anything.

Question 40

What is the placebo effect?

Answer 40

When the patient expects the treatment to work and so feels better, even though the treatment isn’t doing anything.

Question 41

What are risk factors?

Answer 41

They’re things that are linked to an increased in the likelihood that a person will develop a certain disease during their lifetime.

Question 42

What are some risks factors?

Answer 42

They can be unavoidable - age or gender. Lifestyle factors - smoking, diet, exercise and drinking.

Question 43

How does smoking increase the chance of cardiovascular disease?

Answer 43

Nicotine in cigarette smoke increase heart rate, which creases blood pressure. High blood pressure damages artery walls, which contributes to the build up of fatty deposits in the arteries. These deposits restrict blood flow and increase the risk of a heart attack or stroke. Smoking increases the risk of blood clots forming in arteries, which can restrict or block blood flow, leading to a heart attack or stroke.

Question 44

How do non-communicable diseases effect local areas?

Answer 44

For example, in areas where there are high levels of obesity, smoking or excess alcohol consumption, there’s likely to be a high occurrence of certain non-communicable diseases. This can put pressure on resources (money, beds, staff) of local hospitals.

Question 45

How are non-communicable diseases costly?

Answer 45

They’re costly at a national level because the national health service provides resources for the treatment of patients all over the UK. Sometimes, people suffering from a non-communicable disease may not be able to work. A reduction in the number of people able to work can affect a country’s economy.

Question 46

What does body mass index indicate?

Answer 46

If you’re under or overweight.

Question 47

How do you calculate BMI?

Answer 47

Weight (kg) / height (m)^2 You then use a table to find what category they’re in.

Question 48

Why isn’t BMI always reliable?

Answer 48

For example athletes have a lot of muscle, which weighs more than fat, so they can come out with a high BMI even though they’re not overweight.

Question 49

What is the formula for waist-to-hip ratio?

Answer 49

Waist circumference / hip circumference.

Question 50

What is cholesterol?

Answer 50

A fatty substance that the body needs to make things like cell membranes.

Question 51

What does too much cholesterol cause?

Answer 51

To much in the blood can cause fat deposits to build up in arteries, restricting blood flow. It can also cause blood clots, which can lead to heart attacks or strokes.

Question 52

What lifestyle changes can be used to treat CVD?

Answer 52

People will be encouraged to eat a healthy, balanced diet, exercise regularly, lose weight if necessary and stop smoking.

Question 53

Why is medications used to help with CVD?

Answer 53

Lifestyle changes aren’t always enough, so sometimes medicines are needed too.

Question 54

What surgical procedures can be used to help with CVD?

Answer 54

Stents keep arteries open, making sure blood can pass through to the heart muscles, lowering the risk of heart attack. Coronary bypass surgery - if part of the blood vessel is blocked, a piece of healthy vessel taken from else where can be used to bypass the blocked section. The whole heart can be replaced by a donor, however the new heart doesn’t always start pumping properly and drugs have to be used.

Question 55

What are stents?

Answer 55

They’re tubes that are inserted inside arteries.

Question 56

What is the problem with using stents?

Answer 56

Over time, the artery can narrow again as stents can irritate the artery and make scar tissue grow. The patient also has to take drugs to stop blood clotting on the stent.