Which of the following statements about the DNA in one of your brain cells is true? a. Most of the DNA codes for protein. b. The majority of genes are likely to be transcribed. c. It is the same as the DNA in one of your liver cells. d. Each gene lies immediately adjacent to an enhancer.

Key Concepts

Gene Expression

Gene expression is the process by which information from a gene is used to synthesize functional gene products, typically proteins. In eukaryotic cells, this involves transcription of DNA into messenger RNA (mRNA), followed by translation into proteins. Not all genes are expressed in every cell type, which is why different cells, like brain and liver cells, can have distinct functions despite having the same DNA.

Genomic DNA

Genomic DNA refers to the complete set of DNA, including all of its genes, present in an organism. In humans, nearly all cells contain the same genomic DNA, meaning that the DNA in a brain cell is essentially identical to that in a liver cell. However, the expression of specific genes varies between cell types, leading to their specialized functions.

Enhancers and Gene Regulation

Enhancers are regulatory DNA sequences that can increase the likelihood of transcription of specific genes. They can be located far from the gene they regulate and interact with transcription factors to enhance gene expression. While not every gene is immediately adjacent to an enhancer, these elements play a crucial role in the precise regulation of gene expression in different cell types.