Refer to the figure below. If the nucleus evolved via a mechanism such as that shown in the figure, which statement would be true of the nuclear envelope?
A) It consists of one membrane layer.
B) It consists of two membrane layers.
C) It is not connected to the endoplasmic reticulum.
D) It has properties different from the cell membrane.
E) It contains a membrane layer that originated from the cell membrane of another cell.

Question

Refer to the figure below.  If the nucleus evolved via a mechanism such as that shown in the figure, which statement would be true of the nuclear envelope?
A) It consists of one membrane layer. 
B) It consists of two membrane layers. 
C) It is not connected to the endoplasmic reticulum. 
D) It has properties different from the cell membrane. 
E) It contains a membrane layer that originated from the cell membrane of another cell.

Quizplus · Accepted Answer

The figure shows a possible mechanism for the evolution of the nuclear envelope from the plasma membrane of an ancestral prokaryotic cell. According to this model, the plasma membrane invaginated and formed a double layer of membrane surrounding the genetic material (represented by the orange oval). The outer layer of the membrane is continuous with the endoplasmic reticulum (ER), while the inner layer is continuous with the outer layer at various nuclear pores. Therefore, the nuclear envelope consists of two membrane layers (option B) and is connected to the ER (option C is false). The nuclear envelope might share some properties with the cell membrane (option D), but this is not explicitly mentioned in the model. It's also possible that the origin of the nuclear envelope involved the fusion of two membranes, rather than the invagination of one (option E), but the figure doesn't provide enough information to rule out this possibility.

Refer to the Figure Below