Unit 12

Question 1

What is the main difference between syndromes and single gene disease

Answer 1

SDG cant be seen by karyotyping

Question 2

What are genetic disorders affected by

Answer 2

Location, race and religion

Question 3

What does isolation of a population and incest have in common

Answer 3

Reduces the gene pool, raises the frequency of diseases since carriers are more likely to couple

Question 4

How can you detect genes in your family

Answer 4

-develop a family pedigree: provides a probability
-DNA sequence analysis: definitive results

Question 5

How do you draw a family pedigree

Answer 5

Ben

Question 6

Do single gene defects follow mendelian genetics

Answer 6

Yes, it can either be on the dominant or recessive allele and the patterns of inheritance are either autosomal or x-linked

Question 7

What is the consequence of an x-linked single gene defect

Answer 7

Females can be cariers but men are affected

Question 8

What does autosomal recessive gene defects mean for different genotypes

Answer 8

AA=normal
Aa=carries
aa=affected

Question 9

What are some examples of autosomal recessive gene defects?

Answer 9

-cystic fibrosis
-phenylketonuria pku
-Tay sachs
-sickle cell

Question 10

What are the characteristics of cystic fibrosis

Answer 10

-most common lethal gene in canada
-mutation in a membrane protein involved in chloride ion transport. Higl Cl- causes mucus to build up in pancreas, lungs and digestive tract
-poor absorbtion of food, chronic bronchitis and bacterial infections

Question 11

What are the characteristics of PKU

Answer 11

-dysfunctional enzyme on chromosome 12
-phenylanine accumulates in blood, causes mental retardation by 5 years
-treatable by strict diet free of tyrosine

Question 12

What are the characteristics of Tay Sachs

Answer 12

-defective enzyme, fat accumulates in brain, death between 3 to 5 years

Question 13

What are the characteristics of sickle cell

Answer 13

-defective protein in red blood cell, causes improper folding
-clogs capillaries with misshaped blood cells

Question 14

What does autosomal dominant gene defects mean for different genotypes

Answer 14

AA=affected
Aa= affected
aa=not affected

Question 15

What are some examples of autosomal dominant gene defects

Answer 15

-marfan syndrome: tall, long limbs, spider-like fingers-bones dont stop growing
-huntingtons-late onset degenerative neurological disease, terminal

Question 16

What are some x-linked recessive gene mutation examples

Answer 16

-colour blindness
-duchenne muscular dystrophy
-hemophilia

Question 17

Why are males more affected by c-linked recessive gene defects

Answer 17

Because they only need one allele to be infected