Cellular Biology and Mitochondrial DNA

Mitochondrial DNA

• Mitochondrial DNA (mtDNA) is a circular, double-stranded molecule found inside mitochondria
• mtDNA is inherited solely from mother to child, as only egg cells contribute mitochondria to the zygote
• Human mtDNA consists of approximately 16,500 base pairs, encoding 37 genes
• mtDNA mutations can cause various diseases, including mitochondrial myopathies and neurodegenerative disorders

Cellular Respiration

• Cellular respiration is the process by which cells generate energy from glucose
• It involves three stages: glycolysis, the citric acid cycle, and oxidative phosphorylation
• Mitochondria play a crucial role in cellular respiration, as they are the site of oxidative phosphorylation
• During oxidative phosphorylation, energy from NADH and FADH2 is used to generate ATP through the electron transport chain

Energy Production

• Mitochondria are often referred to as the "powerhouses" of the cell, as they generate most of the cell's energy in the form of ATP
• The energy-producing process in mitochondria involves the electron transport chain, which generates a proton gradient across the inner mitochondrial membrane
• This gradient is used to drive the production of ATP through the process of chemiosmosis
• Mitochondria can produce ATP through two main mechanisms: oxidative phosphorylation and substrate-level phosphorylation

Mitochondrial Dynamics

• Mitochondrial dynamics refer to the processes of mitochondrial fusion, fission, and movement
• Mitochondrial fusion allows for the exchange of mitochondrial contents and the formation of a network of interconnected mitochondria
• Mitochondrial fission is the process by which mitochondria divide into smaller units, allowing for the removal of damaged or dysfunctional mitochondria
• Mitochondrial movement is crucial for the distribution of mitochondria throughout the cell and for the regulation of cellular energy metabolism
• Mitochondrial dynamics are important for maintaining mitochondrial function and preventing the accumulation of damaged or dysfunctional mitochondria.

Mitochondrial DNA

• Mitochondrial DNA is a circular, double-stranded molecule with approximately 16,500 base pairs, encoding 37 genes.
• Mitochondrial DNA is inherited solely from mother to child due to the maternal contribution of mitochondria to the zygote.

Cellular Respiration

• Cellular respiration is a three-stage process generating energy from glucose: glycolysis, citric acid cycle, and oxidative phosphorylation.
• Mitochondria are the site of oxidative phosphorylation, where energy from NADH and FADH2 is used to generate ATP through the electron transport chain.

Energy Production

• Mitochondria are the primary site of ATP production in the cell, generating energy through the electron transport chain and chemiosmosis.
• The electron transport chain generates a proton gradient across the inner mitochondrial membrane, driving ATP production.
• Mitochondria produce ATP through two main mechanisms: oxidative phosphorylation and substrate-level phosphorylation.

Mitochondrial Dynamics

• Mitochondrial dynamics involve mitochondrial fusion, fission, and movement.
• Mitochondrial fusion allows for the exchange of mitochondrial contents and the formation of interconnected mitochondria.
• Mitochondrial fission enables the removal of damaged or dysfunctional mitochondria by dividing into smaller units.
• Mitochondrial movement is crucial for distributing mitochondria throughout the cell and regulating cellular energy metabolism.
• Mitochondrial dynamics maintain mitochondrial function and prevent the accumulation of damaged or dysfunctional mitochondria.

Mitochondrial DNA

• Mitochondrial DNA is a separate genetic material from nuclear DNA and is circular and double-stranded.
• In humans, mtDNA consists of 16,569 base pairs and is present in multiple copies per mitochondrion.
• mtDNA encodes 13 proteins involved in energy production and 24 RNA molecules (tRNAs and rRNAs).

Mitochondrial Function

• Mitochondria are the site of cellular respiration, generating energy for the cell through cellular respiration.
• Cellular respiration involves three stages: glycolysis, citric acid cycle, and electron transport chain and oxidative phosphorylation.
• The citric acid cycle and electron transport chain take place in the mitochondria, producing ATP through oxidative phosphorylation.

Energy Production

• The electron transport chain pumps protons across the inner mitochondrial membrane, generating a proton gradient.
• ATP synthase uses this gradient to generate ATP from ADP and Pi.
• The energy yield from one glucose molecule is 36-38 ATP molecules.

Inheritance and Mitochondrial Diseases

• Mitochondrial DNA is inherited solely from the mother (maternal inheritance).
• Mutations in mtDNA can cause mitochondrial diseases.

Mitochondrial Dynamics

• Mitochondrial dynamics refer to the processes of mitochondrial fission, fusion, and motility.
• These processes are regulated by various proteins and signaling pathways.
• Mitochondrial dynamics are implicated in cellular processes such as apoptosis, cell signaling, and mitochondrial quality control.