How can epigenetic changes alter the amount of proteins that are made by a cell?

• A. By adding chemical groups to DNA or histones to regulate gene expression
• B. By changing the amino acid sequence of proteins
• C. By directly increasing the number of ribosomes in the cell
• D. By modifying the DNA sequence to increase transcription

Answer: (A)

Verified step by step guidance

1. Understand that epigenetic changes refer to modifications that affect gene expression without altering the DNA sequence itself.
2. Recognize that one common form of epigenetic change is the addition of chemical groups, such as methyl or acetyl groups, to DNA or histone proteins. This can influence how tightly DNA is wound around histones, affecting gene accessibility.
3. Consider how these chemical modifications can either enhance or suppress the transcription of genes. For example, DNA methylation typically represses gene expression, while histone acetylation usually enhances it.
4. Realize that by regulating gene expression, epigenetic changes can alter the amount of mRNA produced, which in turn affects the amount of protein synthesized by the cell.
5. Note that epigenetic changes do not involve altering the amino acid sequence of proteins, increasing ribosome numbers, or modifying the DNA sequence itself, but rather they regulate the expression of genes at the transcriptional level.