Okuma AnlamaSoru #11476
Epigenetics: Beyond the Genetic Code
For decades following the discovery of the DNA double helix, biological dogma dictated that an organism's hereditary destiny was rigidly determined by its static genetic code. However, the burgeoning discipline of epigenetics has upended this deterministic paradigm. Epigenetics investigates heritable changes in gene expression that do not involve alterations to the underlying DNA sequence. Instead, chemical modifications—such as DNA methylation and histone acetylation—act as molecular switches, turning specific genes on or off in response to environmental stimuli. Factors including nutritional intake, chronic psychosocial stress, exposure to airborne pollutants, and physical exercise can leave lasting epigenetic marks. Remarkably, recent mammalian research suggests that certain environmentally induced epigenetic alterations can be transmitted across generations, implying that the lifestyle choices of ancestors may influence the metabolic and psychological health of their descendants. According to the passage, epigenetics modifies cellular traits by ----.
- A)replacing human DNA with synthetic bacterial genetic polymers
- B)permanently deleting harmful genes from chromosomes during infancy
- C)forcing all somatic cells to transform into pluripotent stem cells
- D)altering how genetic sequences are read and expressed without changing the underlying DNA code
- E)eliminating the requirement for messenger RNA during protein synthesis
Cevabı ve çözümü göster
Doğru cevap: D) altering how genetic sequences are read and expressed without changing the underlying DNA code
Çözüm: Metinde epigenetiğin DNA baz dizilimini değiştirmeden (without altering the underlying DNA sequence) genlerin açılıp kapanmasını ve okunmasını kimyasal işaretlerle düzenlediği anlatılır. Doğru cevap D'dir.