Topic 5 - Health, Disease And The Development Of Medicines (Unfinished)

Question 1

Diseases can be..

Answer 1

Communicable or non-communicable

Question 2

How does the WHO define health?

Answer 2

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

This means that if someone if very physically fit, they can still be unhealthy due to mental health disorders or social isolation

Question 3

What are communicable diseases?

Answer 3

Diseases that can be caught and passed on from one organism to another

Question 4

What are non-communicable diseases?

Answer 4

Diseases that can’t be transmitted

Question 5

What bacterium causes cholera?

Answer 5

Vibrio cholerae

Question 6

What pathogen causes malaria?

Answer 6

A protist

Question 7

What pathogen causes ebola?

Answer 7

A virus

Question 8

What is a pathogen?

Answer 8

A microorganism that causes disease

Question 9

What pathogen causes chalara ash dieback?

Answer 9

A fungus

Question 10

How is cholera spread?

Answer 10

Via contaminated water

Question 11

How is ebola spread?

Answer 11

Via bodily fluids

Question 12

How can you prevent tuberculosis?

Answer 12

Infected people should avoid public areas, practise good hygiene and sleep alone
Homes should be well ventilated

Question 13

How can you prevent ebola?

Answer 13

By isolating infected individuals and sterilising areas where the virus may be present

Question 14

How can you prevent malaria?

Answer 14

By using mosquito nets and insect repellents

Question 15

Viruses can only reproduce in living cell

True or false?

Answer 15

True

Question 16

Are viruses cells?

Answer 16

No - they are just a protein coat around a strand of genetic material

Question 17

What are the two different ways that viruses can reproduce?

Answer 17

Lytic pathway

Lysogenic pathway

Question 18

What happens in the lytic pathway?

Answer 18

The virus attaches itself to a specific host cell and injects genetic material

Virus uses proteins and enzymes in the host cell to replicate genetic material and produce components of new viruses

The components assemble and the host cell splits open, damaging the cell and releasing new viruses, which infect more cells

Question 19

What happens in the lysogenic pathway?

Answer 19

The injected genetic material is incorporated into the genome of the host cell (DNA)

The viral genetic material gets replicated along with the host DNA every time the cell divides - but the virus is dormant and so no new viruses are made

Eventually a trigger causes the viral genetic material to leave the genome and enter the lytic pathway

Question 20

What are STI’s?

Answer 20

Sexually transmitted infections

Question 21

What is chlamydia?

Answer 21

Is a bacterium, but behaves like a virus as it needs host cells in order to reproduce

I doesn’t always show symptoms, but it can cause infertility in men and women

Question 22

How can the transmission of chlamydia be prevented?

Answer 22

Can be reduced by wearing a condom, screening individuals so they can be treated for the infection or avoiding sexual contact

Question 23

What is HIV?

Answer 23

Human Immunodeficiency Virus

Will eventually lead to AIDS (Acquired Immune Deficiency Syndrome)

Question 24

What does HIV do?

Answer 24

It kills white blood cells, which are very important in the immune response

Question 25

What causes HIV to develop into AIDS?

Answer 25

When the infected person's immune system deteriorates and eventually fails due to the lack of white blood cells that have been killed by HIV Because of this, the person becomes very susceptible to infections by other pathogens

Question 26

How is HIV spread, and how can transmission of the virus be prevented?

Answer 26

Spread by bodily fluids e.g. blood, shared needles Can be prevented by using a condom. Drug users should avoid sharing needles. Medication can reduce the risk of an infected individual passing on the virus to others Screening and proper treatment are very important

Question 27

What are some physical defences against pathogens that plants use?

Answer 27

Waxy cuticles to stop them or pests from damaging them Cell walls made from cellulose, which acts as an additional barrier if pathogens get past the waxy cuticle

Question 28

What are some chemical defences against pathogens that plants use?

Answer 28

They produce chemicals called antiseptics which kill bacteria and fungal pathogens. They also produce chemicals to deter pests from feeding on their leaves Some chemicals include aspirin and quinine which can also be used to treat human diseases

Question 29

What two things might laboratory based diagnostic testing involve?

Answer 29

- Detecting antigens | - Detecting DNA

Question 30

How can detecting antigens be used to produce accurate identifications of pathogens?

Answer 30

Pathogens have unique molecules on their surface which are called antigens Antigens for a particular pathogen will be present in a plant infected, and it will be detectable in a sample of plant tissue using monoclonal antibodies The detection of the antigen is unique to a particular pathogen and can be diagnosed

Question 31

What do physical and chemical barriers prevent?

Answer 31

Pathogens from entering the body

Question 32

What physical barriers do we have to prevent infection?

Answer 32

The skin acts as a barrier to pathogens, and if it gets damaged then the blood will clot quickly and seal cuts to keep microorganisms out Hairs and mucus in your nose trap particles which could contain pathogens Cells in the trachea and bronchi also produce mucus which traps pathogens. Other cells that line these passages are cilia cells, which are hair like cells which move the mucus away from important organs and towards the back of the throat where it can be swallowed

Question 33

What chemical barriers do we have to prevent infection?

Answer 33

The stomach produced hydrochloric acid - this kills most pathogens that are swallowed The eyes produce a chemical called lysozyme which kills bacteria on the surface of the eye

Question 34

How does the immune system prevent infection if a pathogen enters the body?

Answer 34

White blood cells immediately search for pathogens, and travel all around the body B-lymphocytes are a type of white blood cell that are involved in the specific immune response - this is the immune response to a specific pathogen

Question 35

How does the specific immune response work?

Answer 35

Every pathogen has specific antigens (proteins) on their surface When B-lymphocytes come across an antigen on a pathogen, they produce proteins called antibodies. These bind onto the pathogen so it can be found and destroyed by other white blood cells The antibodies then rapidly flow all around the body to ensure all the pathogens have been killed

Question 36

What do memory lymphocytes do?

Answer 36

Give immunity to later infection

Question 37

How does immunity to a pathogen occur?

Answer 37

When the pathogen first enters, there anent many B-lymphocytes so the response is very slow - the person may show symptoms of the disease until more B-lymphocytes are produced Over time, more of these lymphocytes will be in the blood stream after the pathogen has been destroyed, and these will remain in the blood stream for a long time Memory lymphocytes stay in the body for a long time, so therefore this person becomes immune from the pathogen because they have the ability to respond quickly to the pathogen and prevent infection

Question 38

What is the secondary immune response?

Answer 38

If the same pathogen enters the body after immunity has been reached, then there are more cells that will recognise it and produce antibodies against it This means that the secondary immune response is much faster and stronger The secondary immune response often destroys pathogens before you show any symptoms of the disease

Question 39

What is immunisation?

Answer 39

Usually involved injecting dead or inactive pathogens into the body. These are antigenic (carry antigens) so even though they are harmless to the body, the body still makes an immune response against them This therefore triggers the production of memory lymphocytes, so if the pathogen appears again, then the secondary immune response will be quicker This causes immunity without actually catching the disease and showing symptoms - it is a much quicker way to immunity

Question 40

What are advantages of immunisation?

Answer 40

Big epidemics of a disease can be prevented if a large percentage of people are immunised Even the people who aren't immunised are unlikely to catch the disease because there are fewer people to catch it and pass it on This is called herd immunity Some diseases, such as smallpox, have been virtually wiped out due to immunisation programmes across the world

Question 41

What are disadvantages of immunisation?

Answer 41

Immunisation doesn't always make you immune You can sometimes have a bad reaction to a vaccine - e.g. swelling or potentially something more serious such as a fever and seizures. However, bad reactions are very rare

Question 42

What are monoclonal antibodies?

Answer 42

Identical antibodies

Question 43

How are monoclonal antibodies produced?

Answer 43

From lots of clones of a single B-lymphocyte This means that all the antibodies are identical and will only target one specific protein antigen