Cell Membrane Finished
Cell Membrane
The Cell Membrane-
The cell membrane is a semi-permeable membrane that surrounds the cytoplasm of a cell; the cell membrane is made up of phospholipids, proteins and carbohydrates. Its function is to protect the integrity of the interior of the cell allowing certain substances into the cell, while keeping other substances out.
The phospholipids form a thin, flexible sheet while the proteins float in the phospholipid sheet like an ice berg, and the carbohydrates extend out from the proteins.
The phospholipids are arranged in a bilayer, with their polar, hydrophilic phosphate heads facing outwards, and their non-polar, hydrophobic fatty acid tails facing each other in the middle of the bilayer. This hydrophobic layer acts as barriers to all but the smallest molecules, effectively isolating the two sides of the membranes. Different kinds of membranes can contain phospholipids with different fatty acids, affecting the strength and flexibility of the membrane, and animal cell membranes also contain cholesterol linking the fatty acid together and so stabilising and strengthening the membrane.
Cell membranes have a bilayer structure through which protein materials cross from one layer to another. Some protein molecules only pass partway through the membrane while others pass all the way through. Two types of proteins are contained within the structure of a cell membrane. Integral proteins are embedded inside the membrane structure. Some integrals serve as pathways for ions and molecules to gain entry to the cell.
Peripheral proteins sit on the inner and outer surfaces of the membrane, or may be attached to the ends of an integral protein material. Peripherals play a part in cell signalling processes, and help to maintain the chemical balance inside the cell.
Proteins that span the membrane are usually involved in transporting substances across the membrane.
Proteins on the inside surface of cell membranes are often attached to the cytoskeleton and are
The Cell Membrane-
The cell membrane is a semi-permeable membrane that surrounds the cytoplasm of a cell; the cell membrane is made up of phospholipids, proteins and carbohydrates. Its function is to protect the integrity of the interior of the cell allowing certain substances into the cell, while keeping other substances out.
The phospholipids form a thin, flexible sheet while the proteins float in the phospholipid sheet like an ice berg, and the carbohydrates extend out from the proteins.
The phospholipids are arranged in a bilayer, with their polar, hydrophilic phosphate heads facing outwards, and their non-polar, hydrophobic fatty acid tails facing each other in the middle of the bilayer. This hydrophobic layer acts as barriers to all but the smallest molecules, effectively isolating the two sides of the membranes. Different kinds of membranes can contain phospholipids with different fatty acids, affecting the strength and flexibility of the membrane, and animal cell membranes also contain cholesterol linking the fatty acid together and so stabilising and strengthening the membrane.
Cell membranes have a bilayer structure through which protein materials cross from one layer to another. Some protein molecules only pass partway through the membrane while others pass all the way through. Two types of proteins are contained within the structure of a cell membrane. Integral proteins are embedded inside the membrane structure. Some integrals serve as pathways for ions and molecules to gain entry to the cell.
Peripheral proteins sit on the inner and outer surfaces of the membrane, or may be attached to the ends of an integral protein material. Peripherals play a part in cell signalling processes, and help to maintain the chemical balance inside the cell.
Proteins that span the membrane are usually involved in transporting substances across the membrane.
Proteins on the inside surface of cell membranes are often attached to the cytoskeleton and are
References: http://antranik.org/movement-of-substances-across-cell-membranes/ (Antranik) (2014) (Accessed) https://www.boundless.com/physiology/textbooks/boundless-anatomy-and-physiology-textbook/cellular-structure-and-function-3/transport-across-membranes-42/diffusion-330-11468/ (Boundless) (2014) (accessed) http://www.phschool.com/science/biology_place/biocoach/biomembrane1/transport.html (Phschool) (2014) (accessed) http://www.college-cram.com/study/biology/cell-membranes/passive-transport/ (College) (2010) (accessed)