BIOCEL 06

Which of the following is INCORRECT evidence to support the endosymbiotic theory?

• Mitochondria and bacteria differ in size
• Mitochondria are self-repeating bodies like microscopic organisms
• Mitochondrial ribosomes, and enzymes are similar to the bacteria
• Mitochondria have their own particular DNA
• All are incorrect

Respiratory subunit in mitochondria not encoded by its genome

• complex II
• complex I
• complex III
• complex IV
• complex V

The ________________ are functions of the mitochondria

• All answers are correct
• synthesis/breakdown/interconversion of amino acids and participate in the urea cycle
• cell signaling via ROS and calcium storage
• cell death and biosynthesis
• ATP production and cell metabolism regulation

mitochondrial-nuclear crosstalk is so important for the__________________.

• All answers are correct
• correct functioning of respiratory chain enzymes
• correct folding and assembly of respiratory chain enzymes
• correct import of respiratory chain enzymes
• correct synthesis of respiratory chain enzymes

The nuclear DNA interact with the mitochondria by _________________.

• encoding all components of the protein import machinery
• regulating cell metabolism
• participating in the urea cycle
• they do not interact
• limiting mitochondrial repair system

Are mitochondria the same in every tissue?

• All answers are correct
• No, there are differences between tissues in mitochondrial number, function, protein composition and morphology.
• No, each cell type develops and maintains a specific oxidative phosphorylation (OXPHOS) capacity to satisfy its metabolic and energetic demands
• No, the number of mitochondria in a cell can vary widely by tissue.
• No, mitochondria are found in almost all body cells, except for a few, and they differ among each other cells.

It is a possible source of mutations in mitochondria?

• All answers are correct
• nuclear DNA: mendelian inheritance
• cytoplasmic mtDNA: non-mendelian; maternal inheritance
• X-linked
• loss of wild-type mtDNA

The mtDNA adapt to the_____________.

• Nuclear transcription, cytoplasmic translation and signal sequence
• Nuclear transcription and signal sequence
• Cytoplasmic translation and nuclear transcription
• Signal sequence and cytoplasmic translation
• None is correct

What is the role of mitochondrial fusion and fission? 

• To maintain optimal function in energy generation
• To increase the number of mitochondria in a cell
• To decrease the number of mitochondria in a cell
• To prevent the formation of reactive oxygen species
• To regulate the cell cycle

What is the consequence of defects in the machinery mediating mitochondrial fusion and fission? 

• A range of diseases that especially affect the nervous system
• Increased resistance to oxidative stress
• Increased efficiency in energy generation
• Increased mobility within the cell
• Increased homogenization of the mitochondrial population