Which of the following best describes how a liver cell and skin cell have the exact same DNA sequence and yet look different and perform different functions?
The cells discard the DNA that is not in use.
The cells mutate during transcription.
The proteins are expressed differently in each cell.
The tRNA uses a different sequence in each cell during transcription.
The proteins are expressed differently in each cell.
The proteins are expressed differently in each cell.
Both liver and skin cells contain the exact same DNA sequence, but their appearance and functions differ because they express different proteins. The process of gene expression involves the transcription of DNA into mRNA and the translation of mRNA into proteins. During transcription, specific regions of DNA are transcribed into mRNA, and the mRNA is then translated into proteins. Different cell types regulate gene expression differently, leading to the production of different proteins, which ultimately determines the cell's structure and function.
The correct answer to the question is: The proteins are expressed differently in each cell.
The reason why a liver cell and a skin cell have the exact same DNA sequence but look different and perform different functions is because of differential gene expression. Although all cells in an organism have the same DNA, only a subset of genes within the DNA is "expressed" or activated in a particular cell type at any given time.
Gene expression is the process by which the information encoded in the DNA is converted into functional proteins, which are the building blocks and regulators of all cellular activities. Different combinations of genes being expressed in different cells result in various cell types with distinct structures and functions.
To achieve differential gene expression, cells utilize complex mechanisms involving gene regulation. These mechanisms include transcription factors, DNA methylation, histone modifications, and non-coding RNA molecules. They work together to control which genes within the DNA are turned on or off, when they are activated, and to what extent.
So, even though a liver cell and a skin cell have the same DNA sequence, the proteins they produce differ due to variations in gene expression. This differential protein expression gives rise to the distinct characteristics and functions of each cell type.