According to the widely accepted "fluid mosaic model" cell membranes are semi-fluid, where lipids and integral proteins can diffuse randomly. In recent years, this model has been modified in several respects. In this regard, which of the following statements is incorrect?
Correct answer: A. Proteins can also undergo flip-flop movements in the lipid bilayer
- A. Proteins can also undergo flip-flop movements in the lipid bilayer
- B. Many proteins remain completely embedded within the lipid bilayer
- C. Proteins in cell membranes can travel within the lipid bilayer
- D. Proteins can remain confined within certain domains of the membranes
Explanation
The incorrect statement is A. In the fluid mosaic model, proteins are generally considered to be too large to undergo spontaneous flip-flop movements in the lipid bilayer. Instead, they can undergo lateral diffusion within the membrane.An improved model of the structure of cell membrane was proposed by Singer and Nicolson (1972) widely accepted as fluid mosaic model. According to this, the quasi-fluid nature of lipid enables lateral movement (Flip-flop) of proteins within the overall bilayer. This ability to move within the membrane is measured as its fluidity.
Last updated
About Cell Structure and Function
Animal, plant, prokaryotic and eukaryotic cells are compared through their membranes, cell walls, nuclei and cytoplasmic organelles. The work includes the structures and functions of mitochondria, chloroplasts, ribosomes, endoplasmic reticulum, Golgi apparatus and lysosomes, as well as chromosome organization and the distinction between chromatin and chromosomes.
Practise Cell Structure and Function
2,478 free Cell Structure and Function MCQs from Biology, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Biology questions like this
Biology is on 6 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.