Chapter 6b

Question 1

What is polymorphism?

Answer 1

An allele is the form of a gene that you have – there are many different forms of most genes that still result in “normal” functioning.

Question 2

How does polymorphism occur?

Answer 2

Can be a result of single base pair changes, insertions, deletions, etc.

Question 3

Risk of toxic effects or cancer for an individual depend exposure to a high enough level of the toxin and _____

Answer 3

The individual’s genetic predisposition

Question 4

What is genetic predisposition

Answer 4

Genetic predisposition is reflected by what alleles you have inherited from your parents

Question 5

Is there a lot or a little polymorphism in the human genome?

Answer 5

There is a considerable amount

Question 6

In a clinical trial do all people react the same to the drug?

Answer 6

• no some people will be severely affected and others will be unaffected due to polymorphism

Question 7

Do all diseases have an environmental component that can interact with the genetic predisposition of the individual involved

Answer 7

this is likely

Question 8

Define dominant allel

Answer 8

The form of a gene in a diploid organism that is expressed

Question 9

Define Ecogenetics

Answer 9

Study of variability in genes in response to any environmental agent

Question 10

What is the range of variability in genes?

Answer 10

10 to 40 fold

Question 11

In ecogenetic studies do they just focus on genes expressed in the liver and hepatic portal area

Answer 11

no

Question 12

Define Pharmacogenetics

Answer 12

The study of differences in response of individuals to pharmaceuticals based on genetic variability

Question 13

What is the distribution of disorders caused by different responses to pharmaceuticals based on genetic variability

Answer 13

• 1/3 metabolic defects
• 1/3 receptors/transporters or channel defects
• 1/3 unclassified disorders

Question 14

Define Monogenetic trait

Answer 14

a characteristic that is encoded by a single gene

Question 15

What is an example of a monogenetic trait

Answer 15

phenylketonuria

• Cant convert phe to tyr
• can lead to impaired neural development if not detected and treated with low phe, high tyr diet
• now known to be effected by modified genes

Question 16

Define polygenetic trait

Answer 16

one determined by many genes (i.e. blood pressure, obesity, asthma, ect)

Question 17

what does the number of possible genotypes and phenotypes depend on

Answer 17

how many genes are involved

Question 18

How many genes contribute to a risk of coronary heart disease

Answer 18

100

Question 19

What is the frequency needed for the most common allele in a population for it to be considered polymorphism for modeling

Answer 19

no greater then 0.99 (minor allele frequency must be at least 0.10)
-rare alleles have a frequency of 0.01

Question 20

Explain G6PD as an example of human polymorphism in environmentally relevent susceptibility genes

Answer 20

• Glucose-6-phosphate dehydrogenase is an enzyme thats activity is essential for generating NADPH and the re-oxidation of reduced glutathione
• The antimalaria drug primaquine causes acute hemolytic anemia in some individuals deficient in G6PD

Question 21

Why do we care about NADPH

Answer 21

(electron carrier for biosynthetic processes

Question 22

Why do we care about glutathione

Answer 22

(Helps the cell keep SH groups on proteins and Fe2+ in a reduced state)