Source: HINDU
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Aging is accompanied by a gradual decline in physical and cellular functions. One notable effect is the loss of muscle mass known as sarcopenia which impacts strength, mobility and overall health. Recent research has identified mitochondrial DNA (mtDNA) deletion mutations as a significant contributor to this phenomenon.
Conducted by researchers from the University of California Los Angeles (UCLA) and the University of Alberta.
Older individuals exhibited a two-fold increase in chimeric mitochondrial mRNA linked to deletion mutations. These findings indicate that mtDNA mutations are reliable predictors of biological aging.
Though mtDNA constitutes only a small fraction of the genome, its mutations play a disproportionate role in aging and the decline of cellular functions.
About Mitochondria and mtDNA in detail: IAS GYAN
Mitochondria are cellular organelles responsible for producing energy in the form of adenosine triphosphate (ATP).
They are considered the "powerhouses" of the cell and are vital for muscle contraction and cellular health.
Have their own DNA called mitochondrial DNA (mtDNA) which is distinct from the nuclear DNA found in the cell nucleus.
Contain 13 protein-coding genes and 24 non-coding genes on a circular DNA molecule comprising 16,569 base-pairs.
Inherited solely from the mother as sperm cells do not contribute mitochondria to offspring.
Muscle cells require large amounts of ATP for contraction. This energy is produced by mitochondria making their functionality crucial for maintaining muscle mass.
Aging leads to deletion mutations in mtDNA which cause loss of genetic material and disrupt mitochondrial function.
Mutated mtDNA outcompetes normal mtDNA during replication gradually reducing the proportion of functional mitochondria.
Deletion Mutations: Large segments of mtDNA are lost resulting in smaller dysfunctional mtDNA molecules.
Chimeric Genes: Mutations bring unrelated gene sequences together creating abnormal or chimeric genes. These interfere with the production of normal proteins essential for mitochondrial function.
ATP Production Stops: Dysfunctional mitochondria fail to produce adequate ATP leading to the inability of muscle cells to contract properly.
Cell Death: Muscle cells die when mitochondria cannot meet energy demands leading to muscle mass loss.
About DNA in detail: https://www.iasgyan.in/daily-current-affairs/ecdna
DNA is a molecule composed of two strands forming a double helix. It contains the instructions for all cellular functions.
Nuclear DNA: Contains 3.2 billion base-pairs and encodes approximately 20,000 protein-coding genes.
Mitochondrial DNA: A small circular molecule encoding 13 protein-coding genes. Exists in multiple copies per mitochondrion.
Muscle mass loss with age is intricately linked to mitochondrial dysfunction caused by mtDNA deletion mutations.
Understanding the mechanisms of these mutations provides a foundation for developing interventions to combat aging-related muscle loss.
With advances in genetic research and therapies, it may be possible to delay or prevent sarcopenia ensuring healthier aging.
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PRACTICE QUESTION Q.Consider the following statements about mitochondria:
Which of the statements given above is/are correct? Answer: d) Explanation: Statement 1 is correct. Mitochondria have circular DNA called mitochondrial DNA (mtDNA) separate from the nuclear DNA. They encode some of the proteins necessary for their function. Statement 2 is correct. Mitochondria are inherited exclusively from the mother because sperm cells do not pass their mitochondria to the zygote during fertilization. Statement 3 is correct. Mitochondria are often referred to as the "powerhouses" of the cell because they produce ATP which serves as the energy source for various cellular processes. Thus, all the statements are correct. |
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