GN 311 EXAM 4 QUESTIONS WITH ANSWERS
Alkaptonuria - -Absence of homogentisate oxidase activity
Build-up of homogentisic acid in cartilage, urine, skin, and nails
Can lead to joint problems, heart valve problems, hearing loss
One of the first disease phenotypes correlated with a genotype
-Who experimented with Inborn Errors of Metabolism? - -Archibald Garrod
-Phenylketonuria (PKU) - -Accumulation of phenylpyruvic acid in brain
leading to mental retardation
-Albinism - -No melanin pigment
Vision problems
Recessive disorder
-Example of Protein Mutations: Defective
Structural Protein - -Cystic Fibrosis & Sickle Cell Anemia
-Describe in basic terms what a metabolic pathway is/does. - -Stepwise series of reactions
Each reaction catalyzed by an enzyme
1 gene makes 1 enzyme (Beadle and Tatum, 1941)
(now modified to one gene makes ~one polypeptide)
-What happens iff there is a mutation in a gene coding for a particular enzyme in a
metabolic pathway? - -A metabolic block occurs
-What happens in result of a metabolic block? - -Final end product not formed
Mutant phenotype occurs
Accumulation of Intermediate 2 prior to block
Mutant allele can be passed to next generation
May segregate according to Mendel's laws
-What is a Auxotroph? - -requires some chemical for growth - won't grow on minimal
media
, -What is a Prototroph? - -will grow on minimal media since it is capable of synthesizing all
other nutrients that it needs for growth
-Somatic mutations occur where?
How are they passed to new cells? - -Occurs in nonproductive cells
Are passed to new cells through mitosis, creating a clone of cells having the mutant gene
-Germ-line mutations occur where?
How are they passed to new cells? - -Occur in cells that give rise to gametes
Meiosis and sexual reproduction allow germ-line mutations to be passed to approx. half the
members of the newt generation who will carry the mutation in all of their cells
-What are some lost functions of a mutation at the protein level? - -Complete or partial
absence of protein function
-What are some gained functions of a mutation at the protein level? - -Cell produces
protein that is not normally present
Either new gene product or gene product in new location or at an inappropriate time in
development.
Frequently dominant inheritance.
Example: mutation in a gene that encodes a receptor for a growth factor might cause the
mutated receptor to stimulate growth in the
absence of the growth factor.
-What is a point mutation?
What are the types? - -Results in substitution of 1 base for another
Transition and transversion
-Transition - -purine to purine or pyrimidine to pyrimidine
A to G
G to A
T to C
C to T
-Transversion - -pyrimidine to purine or purine to pyrimidine
Alkaptonuria - -Absence of homogentisate oxidase activity
Build-up of homogentisic acid in cartilage, urine, skin, and nails
Can lead to joint problems, heart valve problems, hearing loss
One of the first disease phenotypes correlated with a genotype
-Who experimented with Inborn Errors of Metabolism? - -Archibald Garrod
-Phenylketonuria (PKU) - -Accumulation of phenylpyruvic acid in brain
leading to mental retardation
-Albinism - -No melanin pigment
Vision problems
Recessive disorder
-Example of Protein Mutations: Defective
Structural Protein - -Cystic Fibrosis & Sickle Cell Anemia
-Describe in basic terms what a metabolic pathway is/does. - -Stepwise series of reactions
Each reaction catalyzed by an enzyme
1 gene makes 1 enzyme (Beadle and Tatum, 1941)
(now modified to one gene makes ~one polypeptide)
-What happens iff there is a mutation in a gene coding for a particular enzyme in a
metabolic pathway? - -A metabolic block occurs
-What happens in result of a metabolic block? - -Final end product not formed
Mutant phenotype occurs
Accumulation of Intermediate 2 prior to block
Mutant allele can be passed to next generation
May segregate according to Mendel's laws
-What is a Auxotroph? - -requires some chemical for growth - won't grow on minimal
media
, -What is a Prototroph? - -will grow on minimal media since it is capable of synthesizing all
other nutrients that it needs for growth
-Somatic mutations occur where?
How are they passed to new cells? - -Occurs in nonproductive cells
Are passed to new cells through mitosis, creating a clone of cells having the mutant gene
-Germ-line mutations occur where?
How are they passed to new cells? - -Occur in cells that give rise to gametes
Meiosis and sexual reproduction allow germ-line mutations to be passed to approx. half the
members of the newt generation who will carry the mutation in all of their cells
-What are some lost functions of a mutation at the protein level? - -Complete or partial
absence of protein function
-What are some gained functions of a mutation at the protein level? - -Cell produces
protein that is not normally present
Either new gene product or gene product in new location or at an inappropriate time in
development.
Frequently dominant inheritance.
Example: mutation in a gene that encodes a receptor for a growth factor might cause the
mutated receptor to stimulate growth in the
absence of the growth factor.
-What is a point mutation?
What are the types? - -Results in substitution of 1 base for another
Transition and transversion
-Transition - -purine to purine or pyrimidine to pyrimidine
A to G
G to A
T to C
C to T
-Transversion - -pyrimidine to purine or purine to pyrimidine
