EBIO 2070 Exam 4 questions and
answers(graded A+)
Patterning Defects - answer -Caused by mutations of intercellular signals
disrupting morphogen gradients
-the loss or expansion of whole body regions or parts of the body
Ex: Sonic Hedge Hog (SHH)- creates a morphogen gradients that patterns
the embryo from medial to lateral; loss of SHH=loss of midline structures
(cyclopia)
Homeotic Transformations - answer -Caused by mutations in transcription
factors (like Hox genes) and can cause body parts to take on the wrong
identity
Tissue Specific CREs - answer -separate CREs that control the expression
of developmental regulators in different tissues
-mutations in these can cause small changes in expression limited to that
tissue -- thought to be the major source of morphological variation
between & within species (morphological evolution)
Pleiotropic Effects - answer -result of mutation of a pleiotropic gene (a
gene with many funtions)
-Ex: developmental regulators are often re-used many times during
development ; SHH is used during dev of the limbs, gut & brain--mutating
SHH causes cyclopia, polydactyly, and brain & gut defects
-mutation in protein coding sequences of developmental regulators
usually results in early embryonic lethality (causes major defects in
multiple organs and structures)
Mutations in what types of genes have (kind of) predictable
consequences? - answer -cell cycle regulators (Ex: CDK, Cyclin) resulting in
cancer
-housekeeping genes (Ex: RNA polymerase, hsitone) resulting in death
, -tissue specific effector genes (Ex: hemoglobin, muscle action, Tyrosinase)
often causing tissue-specific genetic diseases and/or "simple" tissue-
specific variations in function
Mutations in tissue-specific effector genes - answer -often causes tissue-
specific genetic diseases: sickle cell anemia (mutation in hemoglobin),
duchenne muscular dystrophy (mutation in dystrophin protein in muscle
cell membrane), cystic fibrosis (mutation in ion channel in lung
epithelium)
-often causes "simple" tissue-specific variations in function: coat/eye color
(mutation in Tyrosinase melanin production enzyme), flower color
(mutation in "Dfr" red pigment synthesis enzyme)
Features of asexual reproduction - answer -most asexual reproducing
organisms produce clones of themselves by mitosis (clones all have the
same version of every gene (alleles) except for a few spontaneous
mutations (new alleles) each generation)
-Because mutations/alleles cannot be transferred between "families"
(lineages) advantageous mutations/alleles can't spread through a
population easily
-deleterious alleles that arise in a lineage cannot be easily eliminated or
compensated for by "good" alleles
----genetic change in populations of asexually reproducing organisms is
slow & pattern of heredity in asexual organisms is simple & predictable
(kid is essentially a copy of the parent)
Features of sexual reproduction - answer -sexual reproduction involves
the fusion of genetic material from 2 individuals with different sets of
alleles/mutations--> it generates new combinations of alleles/mutations
-mixing of genetic material is complex & often has unexpected results
-patterns of inheritance in sexually reproducing organisms are complex
Sexual Reproduction - answer -sexual species have greater genomic
diversity in their populations, & because of this can respond faster to
environmental change & are more resistant to extinction
-more than 99% of multicellular eukaryotes reproduce sexually
answers(graded A+)
Patterning Defects - answer -Caused by mutations of intercellular signals
disrupting morphogen gradients
-the loss or expansion of whole body regions or parts of the body
Ex: Sonic Hedge Hog (SHH)- creates a morphogen gradients that patterns
the embryo from medial to lateral; loss of SHH=loss of midline structures
(cyclopia)
Homeotic Transformations - answer -Caused by mutations in transcription
factors (like Hox genes) and can cause body parts to take on the wrong
identity
Tissue Specific CREs - answer -separate CREs that control the expression
of developmental regulators in different tissues
-mutations in these can cause small changes in expression limited to that
tissue -- thought to be the major source of morphological variation
between & within species (morphological evolution)
Pleiotropic Effects - answer -result of mutation of a pleiotropic gene (a
gene with many funtions)
-Ex: developmental regulators are often re-used many times during
development ; SHH is used during dev of the limbs, gut & brain--mutating
SHH causes cyclopia, polydactyly, and brain & gut defects
-mutation in protein coding sequences of developmental regulators
usually results in early embryonic lethality (causes major defects in
multiple organs and structures)
Mutations in what types of genes have (kind of) predictable
consequences? - answer -cell cycle regulators (Ex: CDK, Cyclin) resulting in
cancer
-housekeeping genes (Ex: RNA polymerase, hsitone) resulting in death
, -tissue specific effector genes (Ex: hemoglobin, muscle action, Tyrosinase)
often causing tissue-specific genetic diseases and/or "simple" tissue-
specific variations in function
Mutations in tissue-specific effector genes - answer -often causes tissue-
specific genetic diseases: sickle cell anemia (mutation in hemoglobin),
duchenne muscular dystrophy (mutation in dystrophin protein in muscle
cell membrane), cystic fibrosis (mutation in ion channel in lung
epithelium)
-often causes "simple" tissue-specific variations in function: coat/eye color
(mutation in Tyrosinase melanin production enzyme), flower color
(mutation in "Dfr" red pigment synthesis enzyme)
Features of asexual reproduction - answer -most asexual reproducing
organisms produce clones of themselves by mitosis (clones all have the
same version of every gene (alleles) except for a few spontaneous
mutations (new alleles) each generation)
-Because mutations/alleles cannot be transferred between "families"
(lineages) advantageous mutations/alleles can't spread through a
population easily
-deleterious alleles that arise in a lineage cannot be easily eliminated or
compensated for by "good" alleles
----genetic change in populations of asexually reproducing organisms is
slow & pattern of heredity in asexual organisms is simple & predictable
(kid is essentially a copy of the parent)
Features of sexual reproduction - answer -sexual reproduction involves
the fusion of genetic material from 2 individuals with different sets of
alleles/mutations--> it generates new combinations of alleles/mutations
-mixing of genetic material is complex & often has unexpected results
-patterns of inheritance in sexually reproducing organisms are complex
Sexual Reproduction - answer -sexual species have greater genomic
diversity in their populations, & because of this can respond faster to
environmental change & are more resistant to extinction
-more than 99% of multicellular eukaryotes reproduce sexually
