Question

How are membranes thought to be made?

1) Membranes are made de novo.
2) Membranes are made as new entities from pools of proteins and lipids.
3) Membranes arise from pre-existing membranes.
4) Membranes arise as newly made proteins and lipids are inserted into the ER membranes.

Answer 1

Membranes are thought to be made through a process called membrane biogenesis. There are several models to explain how membranes are formed: de novo, from pools of proteins and lipids, from pre-existing membranes, or as newly made proteins and lipids are inserted into ER membranes.

Step-by-step explanation:

Membranes are thought to be made through a process called membrane biogenesis. There are several models to explain how membranes are formed:

1. Membranes are made de novo: This means that membranes are made from scratch, without the use of pre-existing membranes. This model suggests that membranes are assembled through the spontaneous self-assembly of lipids and proteins.
2. Membranes are made as new entities from pools of proteins and lipids: According to this model, membranes are made by combining proteins and lipids from the cellular pool.
3. Membranes arise from pre-existing membranes: This model proposes that membranes are formed by budding or vesicle fusion from pre-existing membranes.
4. Membranes arise as newly made proteins and lipids are inserted into the ER membranes: This model suggests that membranes are formed when newly synthesized proteins and lipids are inserted into the endoplasmic reticulum (ER) membranes.