Fluid Mosaic Model
BGY 2001; SEM 1 2013/2014
Assignment 1 (10 marks)
Answer ALL the questions.
1. Discuss briefly fluid mosaic model for membrane structure. (6 marks)
Answer: The lipids and most of the protein in the plasma membrane are free to bob about, sliding from one location in the membrane to another. Because lipids and proteins move about laterally within the membrane, the membrane is a fluid mosaic of lipids and proteins. The membrane fluid is since the composition of any location on the membrane can change. In the same manner that a patchwork quilt is mosaic (different fabrics making up the whole quilt), so, too is the membrane a mosaic with different regions of membrane being composed of different types of phospholipids and proteins. Cell membranes are semipermeable in the sense that they allow some substances to cross and prevent others from crossing. This characteristic allows cells to maintain a different internal composition from the surrounding solution.
Lipid dan kebanyakan protein di dalam membrane plasma mudah bergerak daripada satu kawasan di dalam membrane ke kawasan lain. Oleh sebab lipid dan protein bergerak di dalam membrane, maka membrane adalah cecair mozek bagi lipid dan protein. Komposisi cecair membrane di dalam lokasi membrane boleh berubah. Membrane dibina daripada pelbagai fosfolipid dan protein yang berbeza. Sel membrane adalah separa telap, iaitu ia membenarkan unsur-unsur tertentu untuk melalui membran dan menghalang unsur-unsur lain daripada memasukinya. Ciri ini membenarkan sel untuk mengekalkan komposisi dalaman yang berbeza daripada larutan di persekitarannya.
2. What is “intercellular cytoplasmic bridges”? Explain and give examples. (4 marks) intercellular bridge, a structure that connects adjacent cells, occurring primarily in the epithelium and other stratified squamous epithelia. It consists of slender strands of cytoplasm that project from the surfaces of adjacent cells and merge at the desmosome. Also called cytoplasmic
Assignment 1 (10 marks)
Answer ALL the questions.
1. Discuss briefly fluid mosaic model for membrane structure. (6 marks)
Answer: The lipids and most of the protein in the plasma membrane are free to bob about, sliding from one location in the membrane to another. Because lipids and proteins move about laterally within the membrane, the membrane is a fluid mosaic of lipids and proteins. The membrane fluid is since the composition of any location on the membrane can change. In the same manner that a patchwork quilt is mosaic (different fabrics making up the whole quilt), so, too is the membrane a mosaic with different regions of membrane being composed of different types of phospholipids and proteins. Cell membranes are semipermeable in the sense that they allow some substances to cross and prevent others from crossing. This characteristic allows cells to maintain a different internal composition from the surrounding solution.
Lipid dan kebanyakan protein di dalam membrane plasma mudah bergerak daripada satu kawasan di dalam membrane ke kawasan lain. Oleh sebab lipid dan protein bergerak di dalam membrane, maka membrane adalah cecair mozek bagi lipid dan protein. Komposisi cecair membrane di dalam lokasi membrane boleh berubah. Membrane dibina daripada pelbagai fosfolipid dan protein yang berbeza. Sel membrane adalah separa telap, iaitu ia membenarkan unsur-unsur tertentu untuk melalui membran dan menghalang unsur-unsur lain daripada memasukinya. Ciri ini membenarkan sel untuk mengekalkan komposisi dalaman yang berbeza daripada larutan di persekitarannya.
2. What is “intercellular cytoplasmic bridges”? Explain and give examples. (4 marks) intercellular bridge, a structure that connects adjacent cells, occurring primarily in the epithelium and other stratified squamous epithelia. It consists of slender strands of cytoplasm that project from the surfaces of adjacent cells and merge at the desmosome. Also called cytoplasmic