Question 1

Direction of shell coiling in the snail Lymnaea peregra is conditioned by a form of extrachromosomal inheritance known as ________.

Accepted Answer

A)   sex-linked inheritance
B)   heteroplasmy
C)   maternal effect
D)   independent assortment
E)   epistasis C

Question 2

How do mitochondria and chloroplasts determine phenotypes? Which characteristics of mitochondria and chloroplasts allow such phenotypes to be inherited? Provide specific examples to illustrate your response.

Accepted Answer

Both mitochondria and chloroplasts possess DNA,which directs the synthesis of proteins.These proteins influence mitochondrial structure and function and,thus,influence the phenotype.Mitochondria are involved in energy conversions in cells (petite strains in yeast); chloroplasts are involved in photosynthesis as well as leaf coloration (iojap in maize).

Question 3

What is the meaning of the term endosymbiotic theory?

Accepted Answer

The endosymbiotic theory states that mitochondria and chloroplasts arose independently about 2 billion years ago from free-living proteobacteria.

Question 4

What is the expression pattern of dominant-negative mutations in petite strains of yeast?

Accepted Answer

A)   Expression of wild-type mitochondria is enhanced.
B)   Expression of mutant mitochondria resembles expression of wild-type mitochondria.
C)   Mitochondria show enhanced capacity of oxidative phosphorylation.
D)   The function of wild-type mitochondria is suppressed.
E)   Mitochondrial membranes become hyperpolarized.

Question 5

The maternal effect in Lymnaea is such that the genotype of the egg determines the direction of shell coiling regardless of the genotype of the offspring.Apparently,the cause of this spectacular maternal effect results from ________.

Accepted Answer

A)   orientation of the spindle apparatus in early cleavage
B)   genophores present in the egg cytoplasm
C)   the F factor exerting its influence on the centrosome
D)   colicins "poisoning" one of the cleavage centers
E)   allelic substitution as demonstrated from RNA injection experiments

Question 6

An example of organelle heredity involves pigmentation in Mirabilis jalapa.

Accepted Answer

A) True 
 B)False

Question 7

In what way do mitochondrial mutations influence phenotype?

Accepted Answer

The answer of In what way do mitochondrial mutations influence...

Question 8

Poky strains in yeast result from suppressive mutations in chloroplast DNA.

Accepted Answer

A) True 
 B)False

Question 9

It is safe to say that a maternal effect is caused by the genotype,not the phenotype,of the parent producing the egg.

Accepted Answer

A) True 
 B)False

Question 10

What is the name of a form of extrachromosomal inheritance that is due to transmission of symbiotic or parasitic microorganisms?

Accepted Answer

The answer of What is the name of a form...

Question 11

Which three classes of macromolecules are encoded by mtDNA?

Accepted Answer

The answer of Which three classes of macromolecules are encoded...

Question 12

Describe the molecular and transmission characteristics of Leber's hereditary optic neuropathy (LHON).

Accepted Answer

The answer of Describe the molecular and transmission characteristics of...

Question 13

List three criteria indicating that a human disorder may be attributable to genetically altered mitochondria.

Accepted Answer

The answer of List three criteria indicating that a human...

Question 14

Molecular/structural orientations (gradients)in an egg are thought to play a significant role in development.What is the origin of such gradients? What evidence indicates that the maternal genotype is involved in providing such gradients?

Accepted Answer

The answer of Molecular/structural orientations (gradients)in an egg are thought...

Question 15

List three organisms that provide examples of organelle heredity.

Accepted Answer

The answer of List three organisms that provide examples of...

Question 16

Direction of shell coiling in Lymnaea peregra is influenced by a maternal effect.

Accepted Answer

A) True 
 B)False

Question 17

Through the study of mitochondrial disorders,scientists have suggested a link between the decline of mitochondrial function and aging.What process appears to be involved in this suspected phenomenon?

Accepted Answer

A)   accumulation of sporadic mutations in the nuclear genome
B)   decline of mutations in the nuclear genome
C)   accumulation of mutations in the mtDNA
D)   recombination of mtDNA and nuclear DNA
E)   recombination among mtDNAs of different mitochondria

Question 18

List two classes of extrachromosomal inheritance and give an example of each.

Accepted Answer

The answer of List two classes of extrachromosomal inheritance and...

Question 19

In what way do chloroplast mutations influence phenotype?

Accepted Answer

The answer of In what way do chloroplast mutations influence...

Question 20

The inheritance of the petite phenotype in yeast is complicated by an interaction of mitochondrial and nuclear genes.What are these complications? Which three categories of petites are commonly described?

Accepted Answer

The answer of The inheritance of the petite phenotype in...

Exam 9: Extranuclear Inheritance

Direction of shell coiling in the snail Lymnaea peregra is conditioned by a form of extrachromosomal inheritance known as ________.

How do mitochondria and chloroplasts determine phenotypes? Which characteristics of mitochondria and chloroplasts allow such phenotypes to be inherited? Provide specific examples to illustrate your response.

What is the meaning of the term endosymbiotic theory?

What is the expression pattern of dominant-negative mutations in petite strains of yeast?

The maternal effect in Lymnaea is such that the genotype of the egg determines the direction of shell coiling regardless of the genotype of the offspring.Apparently,the cause of this spectacular maternal effect results from ________.

An example of organelle heredity involves pigmentation in Mirabilis jalapa.

In what way do mitochondrial mutations influence phenotype?

Poky strains in yeast result from suppressive mutations in chloroplast DNA.

It is safe to say that a maternal effect is caused by the genotype,not the phenotype,of the parent producing the egg.

What is the name of a form of extrachromosomal inheritance that is due to transmission of symbiotic or parasitic microorganisms?

Which three classes of macromolecules are encoded by mtDNA?

Describe the molecular and transmission characteristics of Leber's hereditary optic neuropathy (LHON).

List three criteria indicating that a human disorder may be attributable to genetically altered mitochondria.

Molecular/structural orientations (gradients)in an egg are thought to play a significant role in development.What is the origin of such gradients? What evidence indicates that the maternal genotype is involved in providing such gradients?

List three organisms that provide examples of organelle heredity.

Direction of shell coiling in Lymnaea peregra is influenced by a maternal effect.

Through the study of mitochondrial disorders,scientists have suggested a link between the decline of mitochondrial function and aging.What process appears to be involved in this suspected phenomenon?

List two classes of extrachromosomal inheritance and give an example of each.

In what way do chloroplast mutations influence phenotype?

The inheritance of the petite phenotype in yeast is complicated by an interaction of mitochondrial and nuclear genes.What are these complications? Which three categories of petites are commonly described?