SB5 - Health, Disease and the Development of Medicine ✓

Question 1

SB5a - What are the three type of health?

Answer 1

• Physical well-being: Being free from disease, getting regular excersize, limiting harmful substance etc.
• Mental well-being: How you feel about yourself
• Social well-being: How well you get along with others
  ̶-̶ ̶M̶i̶n̶e̶c̶r̶a̶f̶t̶ ̶h̶e̶a̶l̶t̶h̶:̶ ̶R̶e̶g̶e̶n̶e̶r̶a̶t̶e̶s̶ ̶o̶v̶e̶r̶ ̶t̶i̶m̶e̶

Question 2

SB5a - What is the difference between communicable and non-communicable diseases?

Answer 2

Communicable:
- Caused by pathogens (microorganisms athat cause disease)
- Can be spread between people
Non-communicable:
- Caused by problems in the body and by lifestyle choices
- Cannot be spread between people

Question 3

SB5a - Why maya person be more likely to catch a disease if they’ve already got one?

Answer 3

• One disease damages the immune system, making it easier for other pathogens to cause disease
• A disease can damage the body’s natural physical and chemicla defences making it easier for pathogens to get in
• A disease can stop an organ from functioning correctly, meaning other diseases are mroe likely to occur

Question 4

SB5b - Define malnutrition.

Answer 4

A lack or excess of a specific nutrient in the body

Question 5

SB5b - Describe the defficiency diseases associated with lack of:

1) Protien
2) Vitamin C
3) Vitamin D and/or Calcium
4) Iron

Answer 5

1) Kwashiorkor: enlarged belly, small muscles, failure to grow properly
2) Scurvy: Swelling/bleeding gums, muscle/ joint pains and tiredness
3) Rickets/Osteomalacia: Soft bones/cruved leg bones
4) Anaemia: Less and smaller red blood cells, tiredness

Question 6

SB5b - Why is ethanol (in alcohol) considered a drug and what disease cna it lead to?

Answer 6

• It’s considered a drug because it changes the way in which the body works
• It can lead to liver cirrhosis which is a disease where the liver doesn’t function properly

Question 7

SB5c - Why is an obese person at a higher risk of developing CVD?

Answer 7

Obese people are more likely to have more body fat. More body fat increases risk of CVD

Question 8

SB5c - What is CVD?

Answer 8

Cardiovascular disease is a result of the circulatory system functioning poorly and can lead to many side effects including high blood pressure, heart pains and even heart attacks

Question 9

SB5c - What is BMI and what are its pros and cons?

Answer 9

A measure of weight relative to height calculated by mass ÷ height².
Its good at being a a measurement and comparison between people helping identify if they’re over/underweight or obese etc.
However it doesn’t take into account varying muscle and bone mass and so isn’t always an accurate way of assesing risk.

Question 10

SB5c - Describe how smoking can lead to blood clots.

Answer 10

• Tabacco from smoking will damage artery linings.
• Fat (or plaque) can build up in the artery wall making the artery narrow.
• This will increase blood pressure
• Eventually, the fat will block the whole artery
• White blood cells will form a wall around this causing a clot leading to a heart attack or stroke

Question 11

SB5c - Explain how a stent works.

Answer 11

• A stent is a small mesh inserted into the artery on a delfated balloon.
• Once in place, the balloon is inflated and the stent expands widening the artery
• The balloon is taken out but the stent stays in keeping the artery wide

Question 12

SB5d - Describe and explain the causes, types of baceria, host organisms and symptoms associated with:

1) Cholera
2) Tubercolosis(TB)
3) Chalera dieback

Answer 12

1) Caused by vibrio cholera (bacteria). It’s hosts are animals/humans and it can lead to severe diarrhea and dehydration
2) Caused by mytobacterium tubercolosis (bacteria). It’s hosts are humans/animals. It damages lung tissue leading to coughing fever and tiredness
3) Caused by the fungus chalara and affects trees/plants. Lesions on trunks and leaves die earlier than usual

Question 13

SB5d - Describe and explain the causes, types of baceria, host organisms and symptoms associated with:

1) Malaria
2) Typhoid/dysentry
3) Ulcers

Answer 13

1) Caused by the plasmodium ptotist, it infects humans using moquitoes as a vector. Leads to fever weakness, sickness and lack of red blood/liver cells
2) Caused by the salmonella typhi bacteria and infecting animals/humans causing severe diarrhea and dehydration
3) Caused by the heliobacter pylori bacteria and infecting humans causing stomach ulcers

Question 14

SB5d - Why are viruses not ‘true organisms’?

Answer 14

They don’t have a cellular structure and require hosts to survive

Question 15

SB5d - Why are people with HIV likely to develop AIDS?

Answer 15

HIV attacks the white blood cells in your immune system making it weak. Thus the immune system is inable to defend the body from secondary infections effectively

Question 16

SB5f - Describe the lytic cycle.

Answer 16

• Attachment: The viral particle attache sitself to the host receptor cell
• Entry: Nucelic acid of the viruc moves across the membrane into the cell
• Replication: The virus uses the host’s DNA to replicate and synthesise new viral components
• Assembly: The new viral components are assembled into new viruses
• Release: Lysis of infected cell leads to release of fully assembled viral particles

Question 17

SB5f - Describe the lysogenic cycle.

Answer 17

• Attachment: The viral particle attache sitself to the host receptor cell
• The Viral nuclei acids are incorporated into the DNA
• The cell continues to divide
• Replication: The virus uses the host’s DNA to replicate and synthesise new viral components
• Assembly: The new viral components are assembled into new viruses
• Release: Lysis of infected cell leads to release of fully assembled viral particles

Question 18

SB5g - What are the physical defences of plants?

Answer 18

• Waxy layer called the cuticle

- Cell walls

Question 19

SB5g - What are the chemical defences of a plant (giving examples where appropriate)?

Answer 19

• Poisons (in foxgloves)

- Natural insect repellents/alarm substances (Wild potatoes)

Question 20

SB5i - What are physical and chemical barriers?

Answer 20

Barriers to prevent pathogens from infecting the body. Physical barriers stop them getting in and chemical barriers stop them from being effective.

Question 21

SB5i - What are the physical and chemical barriers in the body?

Answer 21

• Skin
• Mucus
• Earwax
• Cilliated cells
• Lysozyme (in saliva and tears)
• Hydrochloric acid in the stomach

Question 22

SB5i - What is lysozyme?

Answer 22

Lysozyme is an enzyme screted by skin and in tears and saliva. It is chemical defence that breaks down the cell walls of types of bacteria.

Question 23

SB5j - What are the two main types of white blood cells involved in the immune response?

Answer 23

• Phagocytes

- Lymphocytes

Question 24

SB5j - How do phagocytes respond to pathogens?

Answer 24

They detect the pathogen and recognise it as a foriegn body. They then ingest the pathogen and use enzymes to destroy it.

Question 25

SB5j - How do lymphocytes respond to pathogens?

Answer 25

• Lymphocytes have antibodies on their surface that are specific to the antigens present on certain pathogens
• The lymphocyte with matching antibodies is activated and will attach to the pathogen and then divide making identical copies of itself
• The lymphocytes secrete antibodies which attach to the antigens of the pathogen and destroy it
• Some lymphocytes remain (Memory lymphocytes)

Question 26

SB5j - Describe and explain the differences in primary and secondary response in terms of lymphocytes.

Answer 26

• The primary response takes a long time between infection and rise in antibody numbers
• The numbers of antibodies produced isn’t that high
• The number of antibodies doesn’t return back to its original value but slightly higher instead
• After the second infection, the secondary response is a lot quicker.
• It also produces a lot more antibodies
• This is because of the already active memory lymphocytes

Question 27

SB5j - Why will memory lymphocytes created after one infection not affect the speed of response for an infection by a different pathogen?

Answer 27

The memory lymphocytes created after one infection have antibodies specific to the antigens of that particular pathogen and won’t work on any othe pathogens.

Question 28

SB5j - How does a vaccination work?

Answer 28

• A vaccination injects inactive/weak pathogens of a disease.
• Lymphocytes with antibodies to tackle these are activated and memory lymphocytes are created
• This means that if that pathogen infects the person after, there will be memory lymphocytes to tackle it quiclkly
• this increases the person’s immunity to this disease as it reduces the severity of the symptoms and the time taken till the infection is dealt with

Question 29

SB5j - If a child is allergic and cannot be vaccinated, how can they still ba sfae from the pathogen?

Answer 29

If around 95% of the people around them are vaccinated there is a very low chance of them getting the disease. This is because all the others either won’t get it or will get rid of it before coming in contact with them. This is called herd immunity.

Question 30

SB5h - Which two methods may a farmer use to identify plant diseases?

Answer 30

• Keys
• Distribution analysis
• Diagnostic testing

Question 31

SB5h - What is a distribution analysis?

Answer 31

A ‘map’ displaying the first infected plant and the location of all the other infected plants. By using othe information such as wind direction, you can deduce how the disease has spread and figure out what the disease is.

Question 32

SB5h - How are keys used to identify plant diseases?

Answer 32

Farmers comare visible symptoms on infected plants to pictures to try and deduce which disease the plant has

Question 33

SB5h - How is diagnostic testing used to identify plant diseases?

Answer 33

Farmers will send off a sample of the infected plant to a lab where they will run tests to work out what the pathogen is. They may also send soil samples to test for nutrients and toxins. This can be very expensive.

Question 34

SB5k - What are antibiotics?

Answer 34

Substances that either kill or bacteria or inhibit their cell processes stopping them from growing/reproducing.

Question 35

SB5k - Why do new antibiotics constantly have to be developed?

Answer 35

Because bacteria are constantly evolving and developing resistance to existing antibiotics.

Question 36

SB5k - Describe the stages of the clinical process.

Answer 36

Pre-clinical development:
- Testing on animals and human tissue to look for
side effects
Clinical development:
- Phase 1:
- Small clinical trial to check for human side effects
- Phase 2:
- Slightly larger sample size looking for the optimum
dosage
- Phase 3:
- Large clinical trial to test effectiveness. Placebo
(decoy) also used to verify this.

Question 37

SB5k CP - What are methods of aseptic techniques?

Answer 37

• Sterilising equipment before use
• Lighting a flame nearby
• Only opening the petir dish slightly
• Using an autoclave
• Cleaning down surfaces before use
• Wearing gloves

Question 38

SB5k CP - Describe the method you would undertake to investigate the growth of bacteria in relation to anitibiotic concentration.

Answer 38

• Using aseptic technique, pour an agar plate, making sure that the bases is covered with a smooth layer of agar
• Open a bottle of bacterial culture without putting it down and pass the neck through the flame of a bunsen burner
• Take out a sterile pipette and without putting it down, draw some bacterial culture
• Slightly open the lid of the petri dish and add some culture. Then place the pipette in disinfectant
• Unwrap a steirle spreader, and open the lid of the petri dish slightly, and spread the culture around in a side to side motion.
• Using a permanent marker, section out the bottom of the petri dish into four sections
• Label one, the control
• Using sterilised forceps dip three paper discs each into a different concentration of antibiotic solution, sterilising between
• Place each disc ina section of the dish (not near the edge)
• Leave for incubation
• Measure clear spaces in each section

Question 39

SB5k CP - How do you measure the radius and the area of a clear spcae?

Answer 39

The length from the centre of the area where there hasn’t been bacterial growth to the edge of this section, is the radius of the clear space.
The area is πr²

Question 40

SB5l - Describe how and why monclonal antibodies are made.

Answer 40

• First, an antigen is injected into a mouse. The mouse produces lymphocytes with antibodies to target this antigen
• However, once a lymphocyte starts producing antibodies, it can no longer divide, and so a cancer cell is grown in culture medium
• The cancer cell is fused with the lymphocyte creating a hybridoma cell whic can both continue to divide and produce lymphocytes

Question 41

SB5l - Why are monoclonal antibodies effective in treating cancer?

Answer 41

Monoclonal antibodies cna be made to specifically target cancer cells. This means that unlike in many other forms of cancer treatment, healthy cells won’t be harmed.

Question 42

SB5l - How are monoclonal antibodies used in pregncancy tests?

Answer 42

Pregnancy tests have two types of monclonal antibodies. One detects hormones that are always found in urine to confirm that its working. The other detects a hormone only only produced after pregnancy

Question 43

SB5l - How are monoclonal antibodies used in cancer diagnosis?

Answer 43

The monoclonal antibodies are made to target cancer cells. They are also made radioactive. Once inserted in the body, they will go to where the tumor is. The radiation given off from the antibodies which help show a PET scanner where the tumors are located.