Part I: Lecture 24

Question 1

AR inheritance: WT allele

Answer 1

A

Question 2

AR inheritance: mutant allele

Answer 2

a

Question 3

AR inheritance: a/a

Answer 3

affected

Question 4

AR inheritance: A/a

Answer 4

carrier

Question 5

AR inheritance: A/__

Answer 5

status unknown

Question 6

How to know if it is AR inheritance

Answer 6

-appears in offspring of unaffected parents
-affects males and females

Question 7

mendelian ratios in humans

Answer 7

1/4 chance of disease ≠ 1 in 4 children have disease
humans have small number of children

Question 8

Phenylketonuria (PKU) gene affected

Answer 8

PAH gene

Question 9

PAH gene makes ___ which does what?

Answer 9

phenylalanine hydrolase
turns Phe into Tyr

Question 10

without PAH, PHE becomes ___ which does what?

Answer 10

phenylpyruvic acid
damages the CNS

Question 11

result of PAH-/PAH- mutations

Answer 11

fetuses protect in utero – mother gets rid of excess Phe
infant has to live on low Phe diet for life

Question 12

low Phe diet

Answer 12

vegetarian diet
no meat and some grains

Question 13

disorders are recessive when ___

Answer 13

heterozygote has WT phenotype (50% of gene activity is sufficient)

Question 14

most mutations in enzyme coding genes are ___ because __

Answer 14

recessive because 50% of enzyme activity is sufficient

Question 15

some genes have many ___

Answer 15

mutant alleles

Question 16

compound heterozygote (def.)

Answer 16

2 different mutant alleles

Question 17

AD inheritance: WT allele

Answer 17

a

Question 18

AD inheritance: mutant allele

Answer 18

A

Question 19

AD inheritance: A/a

Answer 19

affected

Question 20

AD inheritance: A/A

Answer 20

affected to the same or greater extent (often non-viable)

Question 21

How to know if it is AD inheritance

Answer 21

-found in each generation
-affects males and female equally
-father-> son transmission is possible

Question 22

Achndroplasia gene affected

Answer 22

FGFR3 gene

Question 23

FGFR3 gene encodes a ___

Answer 23

receptor for a negative growth factor that prevents cell reproduction and prevent growth of limb bones in fetus

Question 24

mutant allele of FGFR3 gene produces ___

Answer 24

overactive protein that switches immature bone cell to mature cell, preventing growth = short limbs

Question 25

disorders are dominant when ___

Answer 25

heterozygote has mutant phenotype

Question 26

AD disorders when homozygous mutant allele leads to non-viable fetus, the mutant allele is ____ to WT allele

Answer 26

incompletely dominant with (heterozygote phenotype is in between two homozygous phenotype)