Non-Medellin Inheritance Part 2 (Easy)

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the term used to describe the conception of a baby with genetic contributions from three individuals?

Mitochondrial Inheritance Patterns

Heteroplasmy

Three Parent Babies Technology (correct)

Endosymbiosis Theory

What is the origin of mitochondria according to the Endosymbiosis Theory?

Gram-positive bacteria

Gram-negative nonsulfur purple bacteria (correct)

Cyanobacterium

Eukaryotic cell

What benefit did the cyanobacteria or purple bacteria receive from the endosymbiotic relationship?

Ability to carry out photosynthesis

A stable environment with an adequate supply of nutrients (correct)

Genetic material from three individuals

Ability to synthesize more ATP

What is the characteristic that mitochondria gave to cells?

Ability to synthesize more ATP Signup and view all the answers

What is the origin of chloroplasts according to the Endosymbiosis Theory?

Cyanobacterium Signup and view all the answers

What is the term used to describe the evolutionary origin of mitochondria and chloroplasts?

Endosymbiosis Theory Signup and view all the answers

What is the primary function of chloroplasts?

Photosynthesis Signup and view all the answers

Approximately how large is the cpDNA of a tobacco plant in base pairs?

156,000 bp Signup and view all the answers

What type of genes are carried by cpDNA?

Both rRNA, tRNA, and polypeptide genes required for photosynthesis Signup and view all the answers

What is the term for the inheritance pattern of pigmentation in Mirabilis jalapa?

Maternal inheritance Signup and view all the answers

How many genes does the cpDNA of a tobacco plant carry?

Between 110 and 120 genes Signup and view all the answers

Where are many chloroplast proteins coded?

In the nuclear genome Signup and view all the answers

What happens to paternal mitochondria that enter the egg during fertilization?

They are modified by ubiquitin, a small regulatory protein Signup and view all the answers

What is the pattern of transmission of human mitochondrial diseases?

Strict maternal inheritance Signup and view all the answers

Why are mitochondria susceptible to DNA damage?

High oxygen consumption leads to free radicals Signup and view all the answers

What is heteroplasmy in the context of mitochondrial disease?

A mixed population of mitochondria with and without disease-causing mutations Signup and view all the answers

What is the result of heteroplasmy in mitochondrial disease?

Symptoms may vary widely within a given family Signup and view all the answers

What is the purpose of the 'Three Parent Babies' technology?

To prevent the transmission of mitochondrial diseases from mother to child Signup and view all the answers

What is the result of a high ratio of mutant to normal mitochondria in a cell?

The cell becomes more susceptible to disease Signup and view all the answers

What is the significance of the ATPase6 gene in mitochondrial disease?

It encodes a subunit of the mitochondrial ATP-synthase Signup and view all the answers

What is the impact of mitochondrial mutations on the cell?

They can lead to chronic degenerative disorders Signup and view all the answers

What is the inheritance pattern of human mtDNA?

Strictly maternal Signup and view all the answers

Study Notes

Destruction of Sperm Mitochondria After Fertilization

Paternal mitochondria are modified by ubiquitin, a small regulatory protein, which targets organelle destruction.
This process occurs in most mammals, including humans.

Human Mitochondrial Diseases

Human mtDNA is transmitted from the female parent to offspring via the cytoplasm of the egg, resulting in a strict maternal inheritance pattern.
Mitochondrial mutations may occur in somatic cells and accumulate with age, making mitochondria susceptible to DNA damage due to high oxygen consumption and limited repair abilities.
Over 200 human mitochondrial diseases have been identified, which are typically chronic degenerative disorders affecting cells requiring high levels of ATP, such as nerve and muscle cells.

Examples of Human Mitochondrial Diseases

Leber hereditary optic neuropathy: a mutation in one of several mitochondrial genes encoding respiratory chain proteins.
Neurogenic muscle weakness: a mutation in the ATPase6 gene encoding a subunit of the mitochondrial ATP-synthase.
Mitochondrial myopathy: a mutation in a gene encoding a tRNA for leucine.
Maternal myopathy and cardiomyopathy: a mutation in a gene encoding a tRNA for leucine.

Heteroplasmy in Mitochondrial Disease

Heteroplasmy is an important factor in mitochondrial disease, where cells can contain a mixed population of mitochondria with disease-causing mutations.
Disease may occur when the ratio of mutant to normal mitochondria exceeds a threshold value, with symptoms varying widely within a family.

Three Parent Babies

A new reproductive technology involves using a third parent's mitochondria to prevent the transmission of mitochondrial diseases from the mother.
This method was pioneered by John Zhang and colleagues in 2016.

The Endosymbiosis Theory

The endosymbiosis theory describes the evolutionary origin of mitochondria and chloroplasts, which originated from bacteria that took up residence within primordial eukaryotic cells.
Chloroplasts originated from cyanobacteria, while mitochondria originated from Gram-negative nonsulfur purple bacteria.

The Endosymbiotic Relationship

The endosymbiotic relationship provided eukaryotic cells with useful characteristics, including the ability to carry out photosynthesis and synthesize more ATP.
It is unclear how the cyanobacteria or purple bacteria benefitted from the relationship, possibly through a stable environment with adequate nutrients within the eukaryotic cell.

Chloroplast DNA

The main function of chloroplasts is photosynthesis.
Chloroplast DNA (cpDNA) is typically 10 times larger than the mitochondrial genome of animal cells.
The cpDNA of tobacco plants consists of 156,000 bp and carries between 110 and 120 different genes, including rRNA and tRNA genes and many polypeptides required for photosynthesis.

Maternal Inheritance

Carl Correns discovered that pigmentation in Mirabilis jalapa (the four o'clock plant) shows a non-Mendelian pattern of inheritance, which is termed maternal inheritance.
The pigmentation of offspring depends solely on the maternal parent and not at all on the paternal parent.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers the destruction of sperm mitochondria after fertilization and the mechanisms of maternal inheritance of mitochondria in animals.