Genetic & Environmental Causes of Disease

Question 1

5 chemical agents that contribute to disease/injury

Answer 1

• Smoking
• Alcohol
• Dust
• Drugs
• Food

Question 2

Effects of smoking on health x4

Answer 2

• Mutagenic –> cancer
• Inflammation –> COPD (bronchitis, emphysema)
• Nicotinic receptors –> increases b.p. & heart rate
• CO levels –> can cause intrauterine growth retardation

Question 3

Effects of alcohol on health x4

Answer 3

• Larger doses = increased risk of cirrhosis
• Alcohol metabolism:
  - decreases CNS function
  - creates reactive O2 = damages lipid membranes
  - teratogenic –> causes foetal developmental decay

Question 4

Effects of dust on health x3

Answer 4

• Asthma
• Hayfever
• Asbestos –> can damage mesothelium

Question 5

Effects of dugs on health x1

Answer 5

• Side effects of therapeutic drugs

Question 6

Effects of food on health x2

Answer 6

• Allergic reactions

- Some foods could have connections w prevalence of some kinds of cancer

Question 7

3 agents of human disease

Answer 7

• Infectious agents
• Chemical agents
• Physical agents

Question 8

3 physical agents that contribute to disease/injury

Answer 8

• Mechanical injury
• Thermal injury (e.g. hypothermia, fever)
• Radiation (e.g. UV)

Question 9

4 infectious agents that contribute to disease/injury

Answer 9

• Bacteria
• Viruses
• Yeasts
• Fungi

Question 10

Tropism of infectious disease determines… x2

Answer 10

• Which host they’ll infect (e.g. cats not humans)

- Which part of the body will be infected (e.g. salmonella = only GI tract)

Question 11

Modes of infectious transmission x5

Answer 11

• Droplet, blood, water etc.
• Fomites –> transferred to an object = then picked up
• Horizontal –> patient to patient
• Vertical –> mother to child (through placenta)
• Zoonoses –> between species

Question 12

Define heritability

Answer 12

The extent that observed differences are due to genes

Question 13

Familial traits could be due to… x4

Answer 13

• Genes
• Social learning (environment)
• Operant conditions (rewards)
• Chance

Question 14

Types of studies used to measure heritability x4

Answer 14

• Family studies
• Twin studies
• Adoption studies
• Migrant studies

Question 15

Problems with twin studies

Answer 15

• Monozygotic might share more environment than dizygotic –> e.g encouraged to spend more time together

Question 16

Immigration studies look at… (& example)

Answer 16

Change in environment

- e.g. prevalence of disease over time, as environment changes –> if purely genetic, would be unaffected

Question 17

Heritability ‘equation’

Answer 17

Phenotype = enviornment + genes + (genes x environment)

Question 18

Example of gene environment interactions

Answer 18

• An environmental influence could be needed to make a gene work

Question 19

Hardy Weinberg Principle

Answer 19

Relative proportions of different genotypes will remain constant from one generation to another
–> BUT not always true

Question 20

Sickle cell anaemia & malaria

Answer 20

More malaria = more sickle cell

• As sickle cell may protect against it encouraging the trait
• SO heterozygous = blood okay, more malaria-resistant –> survival advantage