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What molecules would be most likely to pass through the lipid bilyer of a plasma membrane?
ions and polar molecules
The part of the cell that is in most direct contact with the environment is the?
The cell membrane, which surrounds the cell and is responsible for which molecules are allowed to diffuse into or out of the cell and which molecules are impermeable to the membrane
Does the plasma membrane of a living cell form an impenetrable barrier between the internal millieu and the environment?
No, the plasma membrane is a selectively permeable barrier that regulates the flow of most molecules across the membrane. The plasma membrane allows waste products to exit the cell and nutrients to enter the cell.
Why do most substances have to be assisted through the plasma membrane?
The plasma membrane is made from tightlypack phospholipids. The plasma membrane prevents polar molecules and large molecules from diffusing freely. Fatty (lipophilic) molecules can easily pass through. since cells often need water soluble materials such as water and sugars, transporters and pores need to be made out of proteins to let those molecules through. One of the most important pumps is the Na+/K+ ATPase pump which maintains gradients of sodium and potassium across the cell membrane
What is use of the plasma membrane?
plasma membrane is the outer most covering of the cell,...
What substance is most likely to passively diffuse across the plasma membrane by dissolving in the membrane?
Nonpolar molecules like lipid-soluble substances (e.g., steroid hormones, oxygen, and carbon dioxide) are most likely to passively diffuse across the plasma membrane by dissolving in the lipid bilayer. This type of diffusion does not require a specific transport protein and can occur directly through the phospholipid bilayer due to the molecules' hydrophobic nature.
Do the hydrophobic tails of plasma membrane promote osmosis?
No, the hydrophobic tails of the plasma membrane do not directly promote osmosis. Osmosis is the movement of water across a selectively permeable membrane from an area of high water concentration to an area of low water concentration. The hydrophilic heads of the plasma membrane allow water molecules to pass through, while the hydrophobic tails help maintain the structural integrity of the membrane.
What makes up most of the molecules in the plasma membrane?
The main component of the cell membrane is phospholipids. These are molecules with a polar (hydrophilic, water-loving) head composed of a phosphate (and usually a choline) and a non-polar (hydrophobic, water-hating) tail composed of fatty acids. In the cell membrane, these phospholipids are arranged in a bilayer - with heads facing the outside and the tails facing each other in the centre of the membrane.
What regulates which substances enter and leave a cell?
The plasma membrane. Carrier proteins and ion channels are parts of the plasma membrane, and aid in diffusion across concentration gradients, as most things don't freely move from one end of the cell membrane to the other. The Sodium-Potassium pump is a major ion channel in the plasma membrane, and regulates the intake of potassium and export of sodium (3 molecules sodium out, 2 molecules potassium in.)
What makes up most of the plasma membrane?
Phospholipid(:
What substance can freely pass through the cell membranes?
Certain steroid hormones, cholesterol for example, can pass through the plasma membrane of the cell. Ions cannot pass through the plasma membrane but requires a channel protein. All cells in our body has phospholipid bilayer plasma membrane.
What is the plasma membrane is primarily made of?
plasma membrane is made up of phospholipids,proteins and short carbohydrate chains.still the structure not visible.so there are several models which explains arrangement of these components.the most accepted is the fluid mosaic model
