B5 - Health, Disease and the Development of Medicines

Question 1

What is the definition of

health?

and who is this according to?

Answer 1

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

according to the World Health Organisation (the WHO)

Question 2

Define

disease.

Answer 2

a condition where part of an organism doesn’t function properly

Question 3

What are the

two different types of disease?

and what do these mean?

Answer 3

1. Communicable - diseases that can be spread between individuals
2. Non-communicable - diseases that can’t be transmitted between individuals

Question 4

Define

pathogen.

Answer 4

an organism that causes communicable diseases

Question 5

What are some exmaples of

pathogens?

(4)

Answer 5

• viruses
• bacteria
• fungi
• protists

Question 6

What are the symptoms/effects of

cholera?

and what pathogen causes this?

Answer 6

diarrhoea

a bacterium called Vibrio cholerae

Question 7

What are the symptoms/effects of

tuberculosis?

and what pathogen causes this?

Answer 7

coughing and lung damage

a bacterium called Mycobacterium tuberculosis

Question 8

What are the symptoms/effects of

malaria?

and what pathogen causes this?

Answer 8

damages red blood cells and (in severe cases) the liver

a protist

Question 9

What are the symptoms/effects of

stomach ulcers?

and what pathogen causes this?

Answer 9

stomach pain, nausea and vomiting

a bacterium called Helicobacter pylori

Question 10

What are the symptoms/effects of

ebola?

and what pathogen causes this?

Answer 10

haemorrhagic fever (a fever with bleeding)

ebola virus

Question 11

What are the symptoms/effects of

chalara ash dieback?

and what pathogen causes this?

Answer 11

leaf loss and bark wounds

a fungus that infects ash trees

Question 12

How does

cholera spread?

and how can you reduce/prevent transmission?

Answer 12

via contaminated water sources

make sure that people have access to clean water supplies

Question 13

How does

tuberculosis spread?

and how can you reduce/prevent transmission?

Answer 13

through air when infected individuals cough

infected people should avoid crowded public spaces, practice good hygiene and sleep alone

their homes should also be well-ventilated

Question 14

How does

malaria spread?

and how can you reduce/prevent transmission?

Answer 14

mosquitos act as animal vectors
(they pass on the protist to humans but don’t get the disease themselves)

use mosquito nets and insect repellent to prevent mosquitos carrying the pathogen from biting people

Question 15

How do

stomach ulcers spread?

and how can you reduce/prevent transmission?

Answer 15

oral transmission
(e.g. swallowing contaminated water or food)

have clean water supplies and hygienic living conditions

Question 16

How does

ebola spread?

and how can you reduce/prevent transmission?

Answer 16

via bodily fluids

isolate infected individuals and sterilise any areas where the virus may be present

Question 17

How does

chalara ash dieback spread?

and how can you reduce/prevent transmission?

Answer 17

it is carried through the air by the wind

(also spreads when diseased ash trees are moved between areas)

remove young, infected ash trees and replant with different species

restrict the import or movement of ash trees

Question 18

Describe the

lytic pathway.

(of viruses) (4 steps)

Answer 18

1. The virus attaches itself to a specific host cell and injects it 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 19

Describe the

lysogenic pathway.

(of viruses) (3 steps)

Answer 19

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 causes the viral genetic material to leave the genome and enter the lytic pathway.

Question 20

Define

STI.

Answer 20

an infection that is spread through sexual contact

Question 21

What is

Chlamidya?

and what effect does it have?

Answer 21

a type of bacterium (that behaves similarly to a virus as it can only reproduce inside host cells)

it can result in infertility

Question 22

How can the

spread of chlamidya be reduced?

(3)

Answer 22

• wearing a condom during sex
• screening indivudals so that they can be treated for the infection
• avoid sexual contact

Question 23

What is

HIV?

and what effect does it have?

Answer 23

Human Immunodeficiency Virus

it kills white blood cells and eventually leads to AIDS

Question 24

What is

AIDS?

Answer 24

Acquired Immune Deficiency Syndrome, when the infected person’s immune system deteriorates and eventually fails - causing the person to be very vulnerable to infections by other pathogens

Question 25

# How is HIV spread? | and how can transmission be prevented? (3)

Answer 25

via infected **bodily fluids** (e.g. blood, semen, vaginal fluids) ## Footnote - use a **condom** when having sex - avoid **sharing needles** - **screening**

Question 26

# What are some physical plant defences? | and how do these work? (2)

Answer 26

1. **Waxy cuticle** - stops pathogens from **entering** them or pests **damaging** them. Also stops **water collecting** on the leaf, which could reduce the risk of infection by pathogens that are **transferred** between plants **in water**. 2. **Cell walls** - form a **physical barrier** against pathogens that make it past the waxy cuticle.

Question 27

# What chemical defences do plants have? | (2)

Answer 27

- produce **antiseptic** chemicals which **kill** bacterial and fungal **pathogens** - produce **chemicals** to **deter pests** from **feeding** on their leaves

Question 28

# What plant chemicals have been used as drugs to treat human diseases? | (or relieve symptoms) (2)

Answer 28

- **Quinine** (from the **bark** of the cinchona tree) - used as **treatment** for **malaria** - **Aspirin** (developed from a chemical dound in the **bark** and **leaves** of **willow trees**) - used to relieve **pain** and **fever**

Question 29

# How can plant diseases be detected? | (4)

Answer 29

- **observations** by plant **pathologists** - changing the **environmental conditions** and observing any **change** in the plant's symptoms - analysing the **distribution** of **diseased plants** - laboratory-based **diagnostic testing**

Question 30

# What are some physical barriers of the human body? | (to stop pathogens from entering) (5)

Answer 30

- **skin** - acts as a **barrier** - **blood clots** - **seals cuts** and keeps microorganisms out - **hairs** and **mucus** in your nose - **trap** particles that could contain **pathogens** - **mucus** in the lungs - **trap** particles that could contain **pathogens** - **cilia** in the lungs- waft the mucus up to the **back of the throat** where it can be **swallowed**

Question 31

# What are some chemical barriers of the human body? | (to stop pathogens from entering) (2)

Answer 31

- the **stomach** produces **hydrochloric acid** that **kills** most pathogens that are swallowed - the **eyes** produce **lysozyme** (in tears) which **kill bacteria** on the **surface** of the eye

Question 32

# Describe the specific immune response by B-lymphocytes. | (4 steps)

Answer 32

1. Every pathogen has **unique molecules** on its surface called **antigens**. 2. When your B-lymphocytes come across an antigen on a **pathogen**, they start to produce **proteins** called **antibodies**. 3. These **bind** to the new invading **pathogen**, so that it can be **found** and **destroyed** by other white blood cells. (The antibodies produced are **specific** to the pathogen.) 4. The **antibodies** are then produced **rapidly** and flow all around the body to find all similar **pathogens**.

Question 33

# How is the secondary immune response faster and stronger? | (4 steps)

Answer 33

1. As well as antibodies, **memory lymphocytes** are also produced in response to a foreign antigen. 2. These remain in the body for a **long time** and '**remember**' a **specific** antigen. 3. If the **same pathogen** enters the body again, there are more cells that will recognise and produce antibodies against it. 4. This means that the **secondary immune response** often gets rid of the pathogen before you begin to show any symptoms.

Question 34

# How does immunisation work? | (3 steps)

Answer 34

1. **Dead** or **inactive** pathogens are injected into the body. 2. The antigens trigger **memory lymphocytes** to be made. 3. If **live** pathogens of the **same type** get into the body, there will already be **memory lymphocytes** that can cause a fast **secondary immune response**.

Question 35

# What are the positives and negatives of immunisation? | (1+, 2-)

Answer 35

+**epidemics** can be prevented if a **large percentage** of the population are **immunised** -immunisation **doesn't always** work - sometimes it doesn't give you **immunity** -you can sometimes have a **bad reaction** to a vaccine

Question 36

# What are monoclonal antibodies?

Answer 36

lots of identical antibodies

Question 37

# What are some uses of monoclonal antibodies? | (3)

Answer 37

- pregnancy tests - cancer treatment - finding blood clots

Question 38

# How are monoclonal antibodies used in pregnancy tests? | (4 steps)

Answer 38

1. The bit of the stick where you **wee** has some **antibodies** to the pregnancy hormone, with **blue beads attached**. 2. The **test strip** has some antibodies to the hormone **stuck on it**. 3. If you're **pregnant**, the **hormone binds** to the **antibodies** on the blue beads and this **binds** to the antibodies on the strip. So, the **blue beads** get **stuck on the strip**, turning it **blue**. 4. If you're **not pregnant**, the urine **still** moves up the stick, carrying the **blue beads** as there's nothing to **stick** these to the **test strip**.

Question 39

# Describe how monoclonal antibodies are used to diagnose cancer. | (4 steps)

Answer 39

1. The monoclonal antibodies are labelled with a **radioactive element**. 2. These are given to the patient through a **drip** and 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 **tumor markers**. 4. A **picture** of the patient's body is taken using a special camera that detects the **radioactivity**.

Question 40

# Describe how monoclonal antibodies can target drugs to cancer cells. | (4 steps)

Answer 40

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 the 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. ## Footnote This **side effects** of this are **lower** than for other drugs or radiotherapy.

Question 41

# Describe how monoclonal antibodies are used to find blood clots. | (4 steps)

Answer 41

1. When blood **clots**, **proteins** in the blood **join together** to form a **solid mesh**. 2. **Monoclonal antiboides** have been developed that **bind** to these proteins. 3. You can attach a **radioactive element** to these antibodies and **inject** them into the body. 4. If you **take a picture** using a camera that picks up the radiation, the blood clot can be detected.

Question 42

# How do antibiotics work?

Answer 42

by **inhibiting processes** in **bacterial cells**, but **not** in the **host organism**

Question 43

# What are the general stages of development of new drugs? | (3)

Answer 43

1. Drug **discovery** 2. Drug **development** (preclinical + clincal testing). 3. Drug **approval**

Question 44

# What are the stages of preclinical testing? | (2)

Answer 44

1. Drugs are tested on **human cells and tissues** in the lab. 2. The drug is tested on **live animals** in order to **test** that the drug **works**, to find out how **toxic** it is, and to find the best **dosage**.

Question 45

# What are the stages of clinical testing? | (3)

Answer 45

1. The drug is tested on **healthy volunteers** to ensure that it doesn't have any **harmful side effects** when the body is working **normally**. 2. If these results are good, the drug can be tested on people suffering from the **illness**. This helps to determine the **optimum dose**. 3. Next, patients are **randomly** put into **two groups**, one is given the **new drug** and the other is given a **placebo**.

Question 46

# What do antibiotics do?

Answer 46

kill bacteria **inside** the body

Question 47

# What do antiseptics do?

Answer 47

kill bacteria **outside** the body

Question 48

# What does an autoclave do?

Answer 48

uses **steam** at a **high pressure** and **temperature** to **kill** any microorganisms present

Question 49

# Give some examples of aseptic technique. | (4) (for the bacterial growth practical)

Answer 49

- **sterilise** the petri dishes and growth medium before use (using an **autoclave**) - **sterilise** the **inoculating loop** by **passing it through a hot flame** - keep liquid bacterial cultures in a **vial** with a **lid** - **cover** the **Petri dish** with a lid after transferring the bacteria to it

Question 50

# Define risk factors.

Answer 50

things that are linked to an **increase** in the **likelihood** that a person will develop a certain disease during their lifetime

Question 51

# Why is smoking a major risk factor associated with cardiovascular disease? | (3)

Answer 51

- **nicotine** in a cigarette smoke **increases heart rate** which **increases 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 52

# What are some risk factors of cardiovascular disease? | (4)

Answer 52

- smoking - drinking too much alcohol - lack of exercies - a diet high in saturated fat

Question 53

# What is the formula for BMI?

Answer 53

BMI = mass / height^2 ## Footnote mass: kg height: m

Question 54

# What BMI is classified as obese?

Answer 54

30 or over

Question 55

# Why isn't BMI always a reliable measure of obesity?

Answer 55

athletes have lots of **muscle**, which have a **higher mass** than fat, so can come out with a **high BMI** even if they're **not overweight**

Question 56

# What is the equation for your waist-to-hip ratio?

Answer 56

waist circumference / hip circumference

Question 57

# What waist-to-hip ratio is classified as obese?

Answer 57

above 1.0 for males above 0.85 for females

Question 58

# What is cardiovascular disease?

Answer 58

any disease associated with your **heart** and **blood vessels**

Question 59

# What are arteries?

Answer 59

**blood vessels** that carry blood **away** from the **heart**

Question 60

# What is cholesterol?

Answer 60

a **fatty substance** that the body needs to make things like **cell membranes** ## Footnote too much cholesterol in the blood can cause fatty deposits to build up in the arteries, restricting blood flow

Question 61

# When does a heart attack occur?

Answer 61

when a **blood clot** in an **artery** supplying the **heart muscle deprives** the heart of **oxygen**

Question 62

# When does a stroke occur?

Answer 62

when a blockage in the **brain** deprives the brain of oxygen

Question 63

# What drugs can reduce the risk of a heart attack or stroke? | (3)

Answer 63

1. **Statins** - **reduce** the amount of **cholesterol** in the **bloodstream** 2. **Anticoaglulants** - make **blood clots less likely to form** 3. **Antihypertensives** - reduce **blood pressure**

Question 64

# What are stents? | and what do they do?

Answer 64

tubes that are inserted inside arteries ## Footnote they keep the arteries open making sure that blood can pass through to heart muscles - lowering the risk of a heart attack

Question 65

# What is coronary bypass surgery?

Answer 65

a surgery where a piece of **healthy blood vessel** is taken and used to **bypass** a blocked blood vessel