Detay bilgiSoru #10762
Epigenetics and Gene Expression
For decades, the central dogma of genetics presumed that an organism's physical and physiological traits were rigidly dictated by the nucleotide sequence encoded in its genome. However, the burgeoning discipline of epigenetics has revealed a vastly more dynamic reality. Epigenetic mechanisms—such as DNA methylation and histone modification—act as biochemical switches that regulate gene expression without altering the underlying genetic code. Environmental influences, including chronic nutritional deficits, psychological trauma, and toxic chemical exposures, can induce methyl groups to bind to specific promoter regions, effectively silencing adjacent genes. Remarkably, some of these epigenetic marks can be preserved during cell division and even passed down across generations, a phenomenon termed transgenerational epigenetic inheritance. Consequently, an individual's health trajectory is shaped not merely by inherited inherited genes, but by the continuous molecular interplay between genome and lifestyle. According to the text, DNA methylation affects genes by ----.
- A)rearranging the order of adenine and thymine pairs in the double helix
- B)permanently deleting nucleotide bases from the chromosome
- C)attaching chemical methyl tags to promoter regions, thereby suppressing or silencing their transcription
- D)transforming somatic cells directly into immortal cancer cells
- E)preventing cell division from ever occurring in mammalian tissues
Cevabı ve çözümü göster
Doğru cevap: C) attaching chemical methyl tags to promoter regions, thereby suppressing or silencing their transcription
Çözüm: Metinde "induce methyl groups to bind to specific promoter regions, effectively silencing adjacent genes" açıkça ifade edilmiştir. Doğru cevap C'dir.