Question

An analysis of four cell types isolated form the same organism is shown here. Based on the evidence in the table, which explanations support the distribution of the proteins into the different cell types? Select ALL that apply.
Responses
A The DNA in each of the four cell types is unique.The DNA in each of the four cell types is unique.
B Only certain genes are expressed in each of the cell types.Only certain genes are expressed in each of the cell types.
C Each cell makes all of the same proteins, but not at the same time.Each cell makes all of the same proteins, but not at the same time.
D Each cell has different DNA mutations that occurred to produce different proteins.Each cell has different DNA mutations that occurred to produce different proteins.
E Specific functions of each cell type are dictated by the proteins that are produced.Specific functions of each cell type are dictated by the proteins that are produced.

Answer 1

B and E.

- B: Different cell types express different subsets of genes (differential gene expression), explaining the different protein profiles.
- E: The proteins produced determine each cell type's specific functions, so different protein complements produce different cell functions.

A and D are incorrect because cells from the same organism generally have the same DNA (not unique sequences), and widespread different mutations producing different proteins in each cell type is not the usual explanation. C is false because differentiated cells do not each make all the same proteins at different times.