A) 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? (1 point)
The cells mutate during transcription.
The proteins are expressed differently in each cell.
The cells discard the DNA that is not in use.
The tRNA uses a different sequence in each cell during transcription.
The proteins are expressed differently in each cell.
A)
Stella described protein synthesis as a process that makes the necessary proteins for the human body to function. She explained the process in
the following steps.
1. DNA is transcribed into mRNA.
2. Amino acids form a chain.
3. The amino acid chain is folded into a protein in the endoplasmic reticulum.
What step did Stella miss in her explanation?
(1 point)
mRNA is translated into amino acids.
DNA is replicated into two daughter cells.
Polypeptide chains express gene traits.
tRNA delivers the DNA to the ribosome.
mRNA is translated into amino acids.
The correct answer is: The proteins are expressed differently in each cell.
To understand why the liver cell and skin cell have the same DNA sequence but different functions, we need to look at the process of gene expression. Gene expression refers to the process by which information from a gene is used to create a functional product, usually a protein.
In every cell, the DNA sequence remains the same, meaning that the instructions for making proteins are present in both the liver cell and skin cell. However, not all genes are active or "turned on" in every cell. Different sets of genes are activated in different types of cells, allowing them to perform specific functions.
The differential protein expression in liver cells and skin cells is achieved through a process called gene regulation. Gene regulation involves a complex network of regulatory proteins, transcription factors, and other molecules that control which genes are turned on or off in a specific cell type. This regulation determines which proteins are synthesized by the cell and in what quantities.
In liver cells, the genes that code for specific liver enzymes or proteins necessary for detoxification may be activated. On the other hand, genes responsible for producing skin-specific proteins, such as keratin, might be activated in skin cells. This differential expression of genes ultimately leads to the development of distinct cellular structures and functions between the two cell types.
Therefore, the proteins being expressed differently in each cell is the correct explanation for why a liver cell and skin cell, even though they have the same DNA sequence, look different and perform different functions.