28-09-21 Genetic and Environmental Cause of Disease Flashcards
1
Q
What are the different reasons a trait could run in a family?
A
- Genes
- Social learning (modelling) e.g. Growing up in a home where loads of alcohol is consumed, you are more likely to consume more alcohol when older.
- Operant conditioning (rewards) e.g. offered money to eat 5 portions of fruit and veg makes you more likely to continue the habit when you are older. This could prevent certain diseases and keep you healthy
- Chance
2
Q
Are heritable traits changeable What are examples of heritable traits that are difficult or easy to change?
A
- Heritable changes can be changeable. Some are easier changed than others
- Some traits change across generations, such as height, which could be due to something like improved diet.
- Some heritable traits/conditions can be easily modified such as:
- Vision – by using glasses
- Hair colour – Using dye
- Mental retardation due to PKG – genetic disease that prevents certain amino acids from reaching the brain. Can be prevented by regulation of diet.
3
Q
How are heritable conditions linked to treatment? Can they be treated without drugs?
A
- Heritable conditions are not closely linked to the type of treatment that works.
- Certain heritable conditions may respond to social and behavioural interventions, without the need for drugs.
- These can include:
- Anxiety treatments
- Bedwetting
- Nail biting
- Diet
- Vision
4
Q
What 4 studies are used to measure heritability and why?
A
- Genes and environment are factors looked at when measuring heritability.
- Studies used include:
- Family studies – people who shared the same environment and share some genes
- Twin studies – Monozygotic (identical) twins - people who share the same environment and the same genes
- Dizygotic (non-identical twins) – Those who share the same environment, but share the same amount of DNA as any other siblings who are not twins
- Adoption studies – Adopted children who have the same environment as their siblings, but share no genes with their siblings
- Separately adopted twins – Have different environments to each other, but the same genes
- Migrant studies – When placing a group in a new population, it can be seen if incidence of disease is caused by unavoidable environmental factors (something in the water), or potentially avoidable factors (poor diet).
5
Q
What are the potential problems in twin studies?
A
- Monozygotic twins (identical) share more environment than dizygotic twins – e.g being treated the same. Whereas dizygotic twins would be encouraged to be individuals
- It is also possible that dizygotic twins didn’t share the same uterine environment during development.
6
Q
How is heritability measured?
A
- Phenotype (characteristic we observe) – genes + environment + (genes x environment)
- This is a population statistic and not related to individuals
7
Q
What are some environmental factors that lead to human disease?
A
- Chemical pollution
- Air pollution
- Climate change
- Poor water quality
- Lack of access to healthcare
- Disease causing microbes
8
Q
What are various different infection agents?
A
- Bacteria
- Viruses
- Fungi
- Yeast
- Protozoa
- Parasites
- Prions
- Tropism – infectious agent that has a preferred environmental. Some are specialised to limbs or even cell types e.g salmonella grows in the GI tract to evade detection
9
Q
What are the different modes of transition?
A
- Droplet
- Faeco-oral
- Venereal
- Blood
- Water
- Food
- Vectors – malaria is transmitted through mosquitoes. Mosquitoes are the vector
- Transmitted through inanimate objects e.g table.
10
Q
What are the different types of transmission?
A
- Horizontal – An infected carrying passing condition on to people around them
- Vertical – From Mother to child through the placenta or breast milk
- Zoonoses – through an animal or animal bite.
- Nosocomial – infection or toxin contracted that exists in a certain location e.g hospital
11
Q
What are the different chemical agents that can cause disease?
A
- Smoking
- Alcohol
- Dust
- Drugs
- Food
12
Q
What diseases can smoking lead to?
A
- Mutagenic - Cancer
- Inflammation – Chronic obstructive pulmonary disease – can affect the bronchitis in the airways
- Endothelial damage (lines inside of blood vessels)
13
Q
What disease can alcohol lead to?
A
- Cancer – acetaldehyde is carcinogenic
- Cirrhosis – scarring of liver caused by long term liver damage.
- Alcoholic fatty liver disease – build up of fat in liver from excess drinking
14
Q
What conditions can be caused by dusts?
A
- Asbestos – mesothelioma – cancer that develops on the lining that covers the outer surface of body organs
- Coal dust – coal workers pneumoconiosis
- Asthma
- Hay fever
15
Q
What diseases can drugs cause?
A
- Cancer
- Stroke
- Lung disease
16
Q
What conditions can food cause?
A
- Diabetes
- Atherosclerosis – narrowing of arteries
- Heart disease
19
Q
What is sickle cell anaemia?
How is it caused?
What is sickle cell trait?
How are they caused?
A
- Sickle cell anaemia is an inherited condition of the red blood cells where there aren’t enough red blood cells to carry oxygen throughout your body.
- This is due to red blood cells being shape like crescent moons.
- This makes it difficult for them to carry oxygen and move through blood vessels.
- Sickle cell anaemia is caused by inheriting a sickle cell gene from both your parents (homozygotes)
- Sickle cell trait is when you only inherit one sickle cell gene from one of your parent’s heterozygotes).
- Those who have sickle cell trait are fine, except the odd sickle cell.
20
Q
What it the link between sickle cell trait and malaria in Africa?
A
- It was found that sickle cell trait is highly prevalent in areas with high rates of malaria in Africa.
- This was because sickle cell trait made the individuals immune to malaria, but did not come with the fatal blood problems of sickle cell anaemia, which offered them a survival advantage over those with normal red blood cells.
- This could have been due to infected cells being destroyed sooner due to the body dealing with occasional sickle cells, or the malaria caused by the parasite grew worse in low oxygen conditions.
21
Q
Why is it so difficult to ascertain genetic vs environmental causes of disease?
A
- Genes and environment interact on a very broad spectrum, and so it can be difficult to determine which one disease is caused by.
22
Q
Give an example in which genes and environment interact to prevent a condition
A
- There are certain individuals that are unable to metabolise alcohol well, which can cause them to become unwell
- This is particularly common in Asia.
- When these people are placed in an alcohol-consuming environment, they are less likely to take part as it makes them feel unwell
- This combination of genes and environment can prevent alcoholism
23
Q
Give an example where environment and genes interact to cause a condition
A
- The condition mesothelioma is highly linked to asbestos
- Not 100% of individuals exposed to asbestos develop mesothelioma, so it is probably that those who did not develop the condition have something in their genes protecting them from this.
