Question

Give reasons:
a)Rough endoplasmic reticulum is the site for the proteins synthesis.
b)Plasma membrane is also called as the selective permeable membrane. ​

Answer 1

Answer:

1)Rough ER has ribosomes attached to its surface. The double membranes of smooth and rough ER form sacs called cisternae. Protein molecules are synthesized and collected in the cisternal space/lumen. When enough proteins have been synthesized, they collect and are pinched off in vesicles.

2)Plasma membrane is also called as the selective permeable membrane because it allows the movement of only selected materials to move in and out of the cell.

Answer 2

(a) The rough ER is named so because it is dotted with tiny ribosomes, giving it a rough, or nubbed appearance under the microscope, kind of like a climbing wall. Together, they make proteins and ship them to all other parts of the cell in a process called protein synthesis.

(b) The plasma membrane is called as selectively permeable membrane because it regulates the movement of substances in and out of the cell. It means that the plasma membrane allows some material to pass through it while at the same time it blocks other material from entering through it.